Trading Arrangements, by Individual Trading Arrangements, by Individual [Table] Trading Arrangement: Trading Arrangement [Axis] Maximum Maximum [Member] Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Interest rate (as percent) Financing Receivable, Interest Rate Financing Receivable, Interest Rate Title of 12(b) Security Title of 12(b) Security Carrying Amount Reported Value Measurement [Member] Subsequent event Subsequent Event [Member] Adjustment to Compensation, Amount Adjustment to Compensation Amount Financial Instrument [Axis] Financial Instrument [Axis] Segment Reporting [Abstract] Segment Reporting [Abstract] Cumulative Net Income Retained Earnings, Unappropriated [Member] Summary of Items Measured at Fair Value on Recurring Basis, Assets Fair Value, Assets Measured on Recurring Basis [Table Text Block] Leases Lessee, Finance Leases [Text Block] Derivative Instrument [Axis] Derivative Instrument [Axis] Summary of Real Property Investment Activity by Segment Estimated Fair Value Of Allocated Purchase Price Of Asset And Liabilities [Table Text Block] Estimated Fair Value of Allocated Purchase Price of Asset and Liabilities. Net cash advances (receipts) on loans receivable Payments for (Proceeds from) Loans Receivable Conversion price (in dollars per share) Debt Instrument, Convertible, Conversion Price Consolidated Entities [Axis] Consolidated Entities [Axis] Exchangeable partnership units Asset acquisition, Exchangeable Partnership Units, Converted into shares, Amount Asset acquisition, Exchangeable Partnership Units, Converted into shares, Amount Entity Common Stock Shares Outstanding Entity Common Stock, Shares Outstanding Seniors Housing Operating Seniors Housing Operating [Member] Seniors Housing Operating. Depreciation and amortization   Other Depreciation and Amortization Amica Senior Lifestyles Acquisition Amica Senior Lifestyles Acquisition [Member] Amica Senior Lifestyles Acquisition Cumulative dividends   Cumulative Dividends Other amortization expenses   Amortization Leases [Abstract] Leases [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax [Abstract] Credit Facility, Tranche Due July 2029 Credit Facility, Tranche Due July 2029 [Member] Credit Facility, Tranche Due July 2029 Consolidated Entities [Domain] Consolidated Entities [Domain] Distributions to noncontrolling interests Payments to Noncontrolling Interests Summary of Investments in Unconsolidated Entities Real Estate Investment Financial Statements, Disclosure [Table Text Block] Seniors Housing Acquisitions Seniors Housing Acquisitions [Member] Seniors Housing Acquisitions Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Summary of Supplemental Balance Sheet Information Related to Leases Assets And Liabilities, Lessee [Table Text Block] Assets And Liabilities, Lessee [Table Text Block] Debt assumed Loans Assumed Maximum amount outstanding at any month end Line of Credit Facility, Maximum Month-end Outstanding Amount Asset Acquisition [Axis] Asset Acquisition [Axis] Net book value Intangible Asset, Excluding Goodwill, after Accumulated Amortization Carrying values of properties securing the debt Debt Instrument, Collateral Amount Outstanding Aggregate Erroneous Compensation Amount Outstanding Aggregate Erroneous Compensation Amount Notes Receivable Notes Receivable [Member] Number of reportable segments Number of Reportable Segments Construction in progress Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Construction In Progress Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Construction In Progress Summary of Notional Amount of Derivatives and Other Financial Instruments Schedule of Derivative Instruments [Table Text Block] Concentration Risk [Table] Concentration Risk [Table] Acquired lease intangibles   Other Finite-Lived Intangible Assets, Gross Reclassified in next 12 months Cash Flow Hedge Gain (Loss) to be Reclassified within 12 Months Operating lease cost: Lease, Cost [Abstract] Entity Address, City or Town Entity Address, City or Town Private Funds Management Business Private Funds Management Business [Member] Private Funds Management Business Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items] Class of Financing Receivable [Domain] Class of Financing Receivable [Domain] Receivables [Abstract] Receivables [Abstract] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Title and Position [Domain] Title and Position [Domain] Peer Group Total Shareholder Return Amount Peer Group Total Shareholder Return Amount Distributions by unconsolidated entities   Proceeds from Equity Method Investment, Distribution, Return of Capital Amount derecognized Transfer of Financial Assets Accounted for as Sales, Amount Derecognized Level 2 Fair Value, Inputs, Level 2 [Member] Total Shareholder Return Vs Peer Group Total Shareholder Return Vs Peer Group [Text Block] Total other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Non-Rule 10b5-1 Arrangement Terminated Non-Rule 10b5-1 Arrangement Terminated [Flag] Revenue Revenue Benchmark [Member] United States UNITED STATES Other expenses Other Expenses Subsequent Event Type [Axis] Subsequent Event Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Additional financing to complete construction Additional Financing to Complete Construction Additional financing to complete construction. Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Collective loan pool Collective Loan Pool 1 [Member] Collective Loan Pool 1 [Member] Total cash invested in real property, net of cash acquired Business Acquisition Purchase Price Allocation Net Cash Invested Business Acquisition Purchase Price Allocation Net Cash Invested Summary Information for Reportable Segments Segment Reporting [Table Text Block] Non-cash acquisition related activity Business Acquisition, Purchase Price Allocation, Non-Cash Business Acquisition, Purchase Price Allocation, Non-Cash Gross repayments Repayments of Lines of Credit Rental income related to (above)/below market tenant leases, net Rental Income Related to Above Below Market Tenant Leases Rental income related to above/below market tenant leases, net Document Period End Date Document Period End Date OP units and DownREIT Units (in shares) Incremental Common Shares Attributable To Redeemable Units Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of operating partnership units. Outstanding shares (in shares) Preferred Stock, Shares Outstanding Principal amount Debt Instrument, Face Amount Gain (loss) on real estate dispositions Gain (Loss) on Sale of Properties Basic: Earnings Per Share, Basic [Abstract] Debt instrument, term (in days) Debt Instrument, Term Effective rate (in percent) Debt Instrument, Interest Rate, Effective Percentage Contributions by noncontrolling interests Proceeds from Noncontrolling Interests Leases Lessor, Operating Leases [Text Block] Gain (loss) on real estate dispositions and acquisitions of controlling interests, net Loss (gain) on real estate dispositions and acquisitions of controlling interests, net   (Loss) gain (loss) on real estate dispositions and acquisitions of controlling interests, net Gain (Loss) on Disposition of Real Estate and Asset Acquisitions, Net Gain (Loss) on Disposition of Real Estate and Asset Acquisitions, Net Lessee, Lease, Description [Line Items] Lessee, Lease, Description [Line Items] Summary of Real Estate Loans Receivable Summary Of Real Estate Loans Receivable [Table Text Block] Summary Of Real Estate Loans Receivable [Table Text Block] Accumulated other comprehensive income (loss)   Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Guarantee of 4.800% Notes due 2028 issued by Welltower OP LLC Guarantee Notes Due 2028 4.800% [Member] Guarantee Notes Due 2028 4.800% Mortgage loans receivable Mortgages [Member] Earnings Per Share Earnings Per Share [Text Block] Earnings per share: Per Share Earnings Per Share [Abstract] Document Fiscal Period Focus Document Fiscal Period Focus Peer Group Issuers, Footnote Peer Group Issuers, Footnote [Text Block] Total liabilities   Liabilities Trading Symbol Trading Symbol Credit Facility, Tranche Due March 2030 Credit Facility, Tranche Due March 2030 [Member] Credit Facility, Tranche Due March 2030 Financing Receivable, Allowance for Credit Loss [Line Items] Financing Receivable, Allowance for Credit Loss [Line Items] Company Selected Measure Name Company Selected Measure Name Sale of Stock [Domain] Sale of Stock [Domain] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Lease liabilities Business Combination, Recognized Identifiable Assets Acquired And Liabilities, Assumed Lease Liability Business Combination, Recognized Identifiable Assets Acquired And Liabilities, Assumed Lease Liability Concentration Risk [Line Items] Concentration Risk [Line Items] Diluted: Earnings Per Share, Diluted [Abstract] Additional fund obligated related to investments Expected additional funding for investments Expected Additional Payments To Develop Real Estate Assets Expected Additional Payments To Develop Real Estate Assets Annual facility fee for each bank based on commitment amount Line of Credit Facility, Commitment Fee Percentage Credit Facility [Domain] Credit Facility [Domain] Operating activities:   Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Real estate property Disposal Group, Including Discontinued Operation, Real Estate Property Disposal Group, Including Discontinued Operation, Real Estate Property Executive Officer Executive Officer [Member] Equity Valuation Assumption Difference, Footnote Equity Valuation Assumption Difference, Footnote [Text Block] Disposal Group Name [Domain] Disposal Group Name [Domain] Line of Credit Facility [Table] Line of Credit Facility [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table] Dilutive potential common shares (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Summary of Real Property Disposition Activity Long-Lived Asset, Held-for-Sale [Table Text Block] Award Timing Predetermined Award Timing Predetermined [Flag] Comprehensive income: Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Adjustment To PEO Compensation, Footnote Adjustment To PEO Compensation, Footnote [Text Block] Level 1 Fair Value, Inputs, Level 1 [Member] Conversion ratio Debt Instrument, Convertible, Conversion Ratio Other real estate loans Other Real Estate Loans Receivables [Member] Other Real Estate Loans Receivables. Employee stock options (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Shares Issued Stock Issued During Period Shares New Issues [Abstract] Stock Issued During Period Shares New Issues [Abstract] Amounts related to stock incentive plans, net of forfeitures Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture Number of sales-type leases Disposal Group, Number Of Sales-Type Leases Disposal Group, Number Of Sales-Type Leases Income (loss) from continuing operations Income (loss) from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Class of Financing Receivable [Axis] Class of Financing Receivable [Axis] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share 2 Properties Disposed 2 Properties Disposed [Member] 2 Properties Disposed Non-real estate loans receivable Non Real-Estate Loans Receivables [Member] Non Real-Estate Loans Receivables [Member] Operating leases Operating Lease, Right-of-Use Asset Number of properties transitioned Disposal Group, Including Discontinued Operations, Number of Properties Transitioned Disposal Group, Including Discontinued Operations, Number of Properties Transitioned Concentration Risk Type [Domain] Concentration Risk Type [Domain] Senior Unsecured Notes and Secured Debt Textual Senior Unsecured Notes And Secured Debt (Textual) [Abstract] Senior Unsecured Notes And Secured Debt (Textual) Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Noncontrolling Interest [Line Items] Noncontrolling Interest [Line Items] Unsecured credit facility and commercial paper Balance outstanding at quarter end Long-Term Line of Credit Common stock Payments of Ordinary Dividends, Common Stock Expiration Date Trading Arrangement Expiration Date 2030 Long-Term Debt, Maturity, Year Four Hedging Relationship [Axis] Hedging Relationship [Axis] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Total equity   Balances at beginning of period Balances at end of period Total accumulated other comprehensive income (loss) Total equity Equity, Including Portion Attributable to Noncontrolling Interest Disposal Group, Including Discontinued Operations [Line Items] Disposal Group, Including Discontinued Operations [Line Items] Senior unsecured notes   Senior unsecured notes   Unsecured Debt Aggregate Pension Adjustments Service Cost Aggregate Pension Adjustments Service Cost [Member] Derivative [Table] Derivative [Table] Net proceeds from the issuance of common stock   Equity and ATM Program issuances Proceeds from Issuance of Common Stock Allowance for credit losses on real estate loans receivable Real Estate Loan Real Estate Loan [Member] Unamortized discounts and premiums, net Debt Instrument, Unamortized Discount (Premium), Net Investing activities:   Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Pro forma net income attributable to common stockholders Business Combination, Pro Forma Information, Pro Forma Income (Loss), after Tax Receivables and other assets Business Acquisition Purchase Price Allocation Receivables and Other Assets Business acquisition purchase price allocation receivables and other assets. Deteriorated loans Deteriorated Loans [Member] Deteriorated Loans [Member] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Available in alternate currencies Available In Alternate Currencies Amount available to borrow for line of credit arrangement in currencies other than USD. Segments [Domain] Segments [Domain] Interest Rate Swap Interest Rate Swap [Member] Total development projects Development Projects Placed Into Service Development projects placed into service. Borrowings Under Credit Facilities and Commercial Paper Program Debt Disclosure [Text Block] Numerator for diluted earnings per share Undistributed Earnings (Loss) Available to Common Shareholders, Diluted Disposal Group Classification [Domain] Disposal Group Classification [Domain] Real estate loans receivable, net of credit allowance   Real estate loans receivable, net of credit allowance Financing Receivable, after Allowance for Credit Loss Secured debt Asset Acquisition, Liability, Secured Debt Asset Acquisition, Liability, Secured Debt Real property held for sale Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Real Estate Held For Sale Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Real Estate Held For Sale Business Combination [Table] Business Combination [Table] PEO Actually Paid Compensation Amount PEO Actually Paid Compensation Amount Secured Debt Secured bond Secured Debt [Member] Business Combination, Asset Acquisition, Transaction between Entities under Common Control, and Joint Venture Formation [Abstract] Foreign currency forward contracts, interest rate swaps and cross currency swaps Foreign Currency Contract, Asset, Fair Value Disclosure Total expenses Costs and Expenses Option exercises (in dollars per share) Stock Issued During Period, Average Price Per Share, Stock Options Exercised Stock issued during period average price stock options exercised. Interest rate (in percent) Debt Instrument, Interest Rate, Stated Percentage Common stock dividends paid Dividends, Common Stock, Cash Total Welltower Inc. stockholders’ equity   Equity, Attributable to Parent Disposed by Sale Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Assets:   Assets: Assets [Abstract] Insider Trading Policies and Procedures [Line Items] Asset acquisition debt assumed Asset Acquisition, Debt Assumed Asset Acquisition, Debt Assumed Unvested restricted shares and units (in shares) Incremental Common Shares Attributable To Dilutive Effect Of Non Vested Restricted Shares Incremental Common Shares Attributable To Dilutive Effect Of Non Vested Restricted Shares Number of operating segments Number of Operating Segments Goodwill Goodwill [Table Text Block] Entity Central Index Key Entity Central Index Key Equity [Abstract] Equity [Abstract] Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year Dividends or Other Earnings Paid on Equity Awards not Otherwise Reflected in Total Compensation for Covered Year [Member] 2026 Long-Term Debt, Maturity, Remainder of Fiscal Year Lease term extension period (in years) Lessee, Lease, Renewal Term Lessee, Lease, Renewal Term Ownership [Axis] Ownership [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair value adjustments and other, net Debt Instruments, Fair Value Adjustments, Net Debt Instruments, Fair Value Adjustments, Net Investment, Name [Axis] Investment, Name [Axis] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Liabilities: Below Market Lease, Net [Abstract] Summary of Geographic Information Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table Text Block] Interest rate margin (in percent) Debt Instrument, Basis Spread on Variable Rate Accumulated Other Comprehensive Income (Loss) Total accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] All Individuals All Individuals [Member] Redeemable noncontrolling interests   Redeemable Noncontrolling Interest, Equity, Other, Fair Value Cash distributions to stockholders   Payments of Dividends Statement [Line Items] Statement [Line Items] Total assets   Amount Total assets Assets Percentage total investments with top five customers (in percent) Percentage Investments With Top Five Customers Percentage investments with top five customers. VIE Variable Interest Entity, Not Primary Beneficiary [Member] Real estate Operating Segments Operating Segments [Member] Share-Based Payment Arrangement, Expensed and Capitalized, Amount Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] At The Market Program At The Market Program [Member] At The Market Program Total liabilities acquired Business Combination, Recognized Liability Assumed, Liability Stock Incentive Plans Share-Based Payment Arrangement [Text Block] PEO PEO [Member] 2028 Long-Term Debt, Maturity, Year Two Beginning balance Ending balance Goodwill Forgone Recovery due to Violation of Home Country Law, Amount Forgone Recovery due to Violation of Home Country Law, Amount Accrued expenses and other liabilities Business Acquisition Purchase Price Allocation Accrued Expenses and Other Liabilities Business acquisition purchase price allocation accrued expenses and other liabilities. Number of properties, reclassified from sales-type lease to operating lease Number Of Properties, Reclassified From Sales-Type Lease To Operating Lease Number Of Properties, Reclassified From Sales-Type Lease To Operating Lease Discontinued Operations, Disposed of by Sale Discontinued Operations, Disposed of by Sale [Member] Noncontrolling Interest, decrease from deconsolidation Noncontrolling Interest, Decrease from Deconsolidation Revolving Credit Facility Revolving Credit Facility [Member] Outstanding shares (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Foreign currency translation Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Summary of Carrying Amounts and Estimated Fair Values of Financial Instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Net income (loss) attributable to common stockholders (in dollars per share) Net income attributable to common stockholders (as reported) (in USD per share) Diluted earnings per share (in dollars per share) Earnings Per Share, Diluted Rental and other revenues related to operating lease payments, variable leases Operating Lease, Variable Lease Income Provision for loan losses, net Provision for loan losses, net Financing Receivable, Credit Loss, Expense (Reversal) Less: Capitalized interest Interest Costs Capitalized Ownership [Domain] Ownership [Domain] Total assets acquired Business Combination, Recognized Asset Acquired, Asset Aggregate unamortized basis difference of joint venture investments Equity Method Investment, Difference Between Carrying Amount and Underlying Equity Share-based Payment Arrangement [Abstract] Share-Based Payment Arrangement [Abstract] Resident fees and services Revenue from Contract with Customer, Excluding Assessed Tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Excluding Redeemable Noncontrolling Interest Other Comprehensive Income (Loss), Net of Tax, Excluding Redeemable Noncontrolling Interest Avir Health Group Avir Health Group [Member] Avir Health Group Denominated in Pounds Sterling United Kingdom, Pounds Financial assets: Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Allowance for credit losses on real estate loans receivable Allowance for Credit Loss Balance at beginning of period Balance at end of period Financing Receivable, Allowance for Credit Loss Noncontrolling interests Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Non-segment/Corporate Other Non-Segment/Corporate Investments [Member] Other Non-Segment/Corporate Investments Over-Allotment Option Over-Allotment Option [Member] Barchester Barchester Healthcare [Member] Barchester Healthcare Number of successive terms Line Of Credit Facility, Number Of Successive Terms Line Of Credit Facility, Number Of Successive Terms Summary of Annual Principal Payments Due on Debt Obligations Schedule of Maturities of Long-Term Debt [Table Text Block] Number of loans Financing Receivable, Number Of Loans Financing Receivable, Number Of Loans Schedule of Equity Method Investments [Table] Equity Method Investment [Table] Title and Position [Axis] Title and Position [Axis] Sale of Stock [Axis] Sale of Stock [Axis] Weighted average interest rate, at point in time (in percent) Long-Term Debt, Weighted Average Interest Rate, at Point in Time Welltower OP Inc Welltower OP Inc [Member] Welltower OP Inc Executive LTIP Unit Awards Executive LTIP Unit Awards [Member] Executive LTIP Unit Awards Loss (gain) on derivatives and financial instruments, net Loss (gain) on derivatives and financial instruments, net   Gain (loss) on derivative instruments hedges recognized in income Derivative, Gain (Loss) on Derivative, Net Summary of Dividend Payments Dividends Declared [Table Text Block] Debt issued Proceeds from Issuance of Debt Non-cash consideration Non-cash consideration Disposal Group, Including Discontinued Operations, Non-Cash Consideration Disposal Group, Including Discontinued Operations, Non-Cash Consideration Senior unsecured notes Notes Payable, Fair Value Disclosure Number of banks in consortium Number of banks in consortium Number of banks in consortium. Collateral Held [Axis] Collateral Held [Axis] Real property owned:   Real Estate Investment Property, at Cost [Abstract] 2.95% Senior Unsecured Notes Due 2027 2.95% Senior Unsecured Notes Due 2027 [Member] 2.95% Senior Unsecured Notes Due 2027 Rule 10b5-1 Arrangement Adopted Rule 10b5-1 Arrangement Adopted [Flag] No. of Loans Financing Receivable Recorded Investment Non Accrual Status Number Of Loans Financing Receivable Recorded Investment Non Accrual Status Number Of Loans Impairment of assets Impairment of assets   Asset, Impairment Loss Operating lease, right-of-use asset, statement of financial position [extensible list] Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration] Issued shares (in shares) Common Stock, Shares, Issued Summary of Financing Receivable, Allowance for Credit Loss Financing Receivable, Allowance for Credit Loss [Table Text Block] Construction in progress   Outstanding construction financings for leased properties Development in Process Product and Service [Domain] Product and Service [Domain] Currency [Axis] Currency [Axis] Class of Stock [Line Items] Class of Stock [Line Items] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Number of assets acquired Number Of Assets Acquired Number Of Assets Acquired Cash disbursed for acquisitions, net of cash acquired Payments to Acquire Other Real Estate Termination Date Trading Arrangement Termination Date Other Commitments [Axis] Other Commitments [Axis] Oakmont Management Group Oakmont Management Group [Member] Oakmont Management Group Noncontrolling Interest [Table] Noncontrolling Interest [Table] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Derivative, loss on derivative Derivative, Loss on Derivative Acquired lease intangibles Business Combination, Recognized Asset Acquired, Identifiable Intangible Asset, Finite-Lived Dispositions, Real Property Held for Sale and Impairment Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Compensation Actually Paid vs. Total Shareholder Return Compensation Actually Paid vs. Total Shareholder Return [Text Block] Net income (loss) Profit Loss Excluding Redeemable Noncontrolling Interest Profit loss excluding redeemable noncontrolling interest. Option expiration period (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period Total dispositions SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate, Cost of Investment in Real Estate Sold Fair Value as of Grant Date Award Grant Date Fair Value Redemption price, percentage (in percent) Debt Instrument, Redemption Price, Percentage Long-Term Debt, Principal Activity [Roll Forward] Long-Term Debt, Principal Activity [Roll Forward] Long-Term Debt, Principal Activity [Roll Forward] Goodwill [Table] Goodwill [Table] Pay vs Performance Disclosure, Table Pay vs Performance [Table Text Block] Resident fees and services Management Service [Member] Arrangement Duration Trading Arrangement Duration Settlement of loan receivable Business Combination, Consideration Transferred, Settlement of Loan Receivable Business Combination, Consideration Transferred, Settlement of Loan Receivable Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Insider Trading Policies and Procedures Not Adopted Insider Trading Policies and Procedures Not Adopted [Text Block] Employee stock purchase program (in shares) Incremental Common Shares Attributable to Dilutive Effect of Employee Stock Purchase Program Incremental Common Shares Attributable to Dilutive Effect of Employee Stock Purchase Program. Gross acquired lease intangibles Intangible Asset, Finite-Lived, before Accumulated Amortization Mint UK Bidco LLC, Properties Under Development Mint UK Bidco LLC, Properties Under Development [Member] Mint UK Bidco LLC, Properties Under Development Total revenues Total revenues Amount Revenues Revenues Income (loss) from unconsolidated entities Loss (income) from unconsolidated entities Income (loss) from unconsolidated entities Income (Loss) from Equity Method Investments Other assets:   Other Assets [Abstract] Forgone Recovery due to Expense of Enforcement, Amount Forgone Recovery due to Expense of Enforcement, Amount Amortization of leased assets Finance Lease, Right-of-Use Asset, Amortization Vesting period for options (in years) Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Goodwill [Roll Forward] Goodwill [Roll Forward] Intangible Asset, Finite-Lived, Class [Domain] Intangible Asset, Finite-Lived, Class [Domain] All Award Types Award Type [Domain] Interest on lease liabilities Finance Lease, Interest Expense Disclosure about Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] 2.8% Senior Unsecured Notes 2.8% Senior Unsecured Notes [Member] 2.8% Senior Unsecured Notes Ownership interest (in percent) Subsidiary, Ownership Percentage, Noncontrolling Owner Debt instrument, convertible, threshold percentage (in percent) Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger Geographical [Axis] Geographical [Axis] Restricted cash   Restricted cash Restricted Cash Weighted average interest rate (actual interest expense divided by average borrowings outstanding) Line of Credit Facility, Interest Rate During Period Financing lease cost: Finance Lease, Costs [Abstract] Finance Lease, Costs [Abstract] Equity interest issued and issuable Business Combination, Consideration Transferred, Equity Interest, Share Issued, Value Total other assets   Other Assets Redemption of OP Units and DownREIT Units Redemption Of OP Units Redemption Of OP Units Legal Entity [Axis] Legal Entity [Axis] Total interest expense Interest Expense, Debt Lessee, Lease, Description [Table] Lessee, Lease, Description [Table] Cash, cash equivalents and restricted cash at beginning of period   Cash, cash equivalents and restricted cash at end of period   Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Non-NEOs Non-NEOs [Member] Other liabilities acquired Asset Acquisition, Other Liabilities Asset Acquisition, Other Liabilities Financing Receivable, Allowance for Credit Loss [Roll Forward] Financing Receivable, Allowance for Credit Loss [Roll Forward] Percentage ownership Equity Method Investment, Ownership Percentage Land and land improvements Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Land Outpatient Medical Outpatient Medical Outpatient Medical [Member] Outpatient Medical. Reclassification To Sales Type Leases Reclassification To Sales Type Leases [Member] Reclassification To Sales Type Leases Investment, Name [Domain] Investment, Name [Domain] Leases Lessee, Operating Leases [Text Block] 2027 Long-Term Debt, Maturity, Year One Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Statistical Measurement [Axis] Statistical Measurement [Axis] Redeemable DownREIT Unitholder interests Redeemable OP unitholder interests Redeemable OP Unit holder Interests Summary of Impact of Derivative Instruments on the Consolidated Statements of Comprehensive Income Derivative Instruments, Gain (Loss) [Table Text Block] Loans related to development and construction of certain properties Total loans made Payments to Develop Real Estate Assets Award Type Award Type [Axis] Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Real Estate Real Estate [Member] Cumulative net income   Retained Earnings (Accumulated Deficit) Product and Service [Axis] Product and Service [Axis] Trading days Debt Instrument, Convertible, Threshold Trading Days All Currencies [Domain] All Currencies [Domain] Investment in loans receivable Advances on loans receivable Payments to Acquire Loans Receivable Totals (in shares) Issuance Of Common Stock Shares Issuance of common stock shares. Awards Close in Time to MNPI Disclosures Awards Close in Time to MNPI Disclosures [Table] Net proceeds from the issuance of secured debt   Proceeds from Issuance of Secured Debt Common stock, $1.00 par value per share Common Stock Common Stock [Member] Lease liabilities Total Lease liabilities Lease, Liability Lease, Liability Canadian Dominated Unsecured Debt Due 2026 Canadian Dominated Unsecured Debt Due 2026 [Member] Canadian Dominated Unsecured Debt Due 2026 Lease expense Operating Lease, Cost Care UK Acquisition Care UK Acquisition [Member] Care UK Acquisition Total construction in progress conversions Construction In Progress Conversions Construction in progress conversions. Contractual interest expense Interest Expense, Debt, Excluding Amortization Derivative Contract [Domain] Derivative Contract [Domain] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Axis] Effect of foreign currency translation Goodwill, Foreign Currency Translation, Gain (Loss) Cash proceeds from real estate dispositions Proceeds from Sale of Property, Plant, and Equipment, Net Of Adjustments Proceeds from Sale of Property, Plant, and Equipment, Net Of Adjustments Total liabilities and equity   Total liabilities and equity   Liabilities and Equity Stock options Share-Based Payment Arrangement, Option [Member] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table] Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Table] Noncontrolling interests   Equity, Attributable to Noncontrolling Interest Segments [Axis] Segments [Axis] Additional 402(v) Disclosure Additional 402(v) Disclosure [Text Block] Totals Gross Proceeds From Issuance Or Sale Of Equity Gross Proceeds From Issuance Or Sale Of Equity Tabular List, Table Tabular List [Table Text Block] Capital in excess of par value   Additional Paid in Capital Name Awards Close in Time to MNPI Disclosures, Individual Name Average amount outstanding (total of daily principal balances divided by days in period) Line of Credit Facility, Average Outstanding Amount Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested Year-end Fair Value of Equity Awards Granted in Covered Year that are Outstanding and Unvested [Member] Equity component of exchangeable debt Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt Equity and ATM Program issuances (in dollars per share) Sale of Stock, Price Per Share Remaining amount authorized to sell Sale Of Stock, Remaining Authorized Amount Sale Of Stock, Remaining Authorized Amount Amount Payments of Ordinary Dividends [Abstract] Adjustment to Compensation: Adjustment to Compensation [Axis] Real estate investments:   Real Estate Investment Property, Net [Abstract] Credit Concentration Risk Credit Concentration Risk [Member] Rule 10b5-1 Arrangement Terminated Rule 10b5-1 Arrangement Terminated [Flag] Aggregate Erroneous Compensation Amount Aggregate Erroneous Compensation Amount Payment to acquire assets Payments to Acquire Productive Assets Secured debt Business Acquisition Purchase Price Allocation Secured Debt Business Acquisition Purchase Price Allocation Secured Debt. Interest paid Interest Paid, Excluding Capitalized Interest, Operating Activity Debt extinguished Debt extinguished Debt extinguished Extinguishment of Debt, Amount Adjustment for net income (loss) attributable to OP Units and DownREIT Units Undistributed Earnings (Loss) Allocated to Participating Securities, Basic Hedging Designation [Axis] Hedging Designation [Axis] Other real estate loans receivable Other Real Estate Loans Receivable [Member] Other real estate loans receivable. Other segment expenses Other General Expense Credit Facility [Axis] Credit Facility [Axis] Denominated in Canadian Dollars Canada, Dollars Name Measure Name Successive term Line Of Credit Facility, Duration Of Successive Term Line Of Credit Facility, Duration Of Successive Term Pay vs Performance Disclosure [Line Items] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] 4 Properties Disposed 4 Properties Disposed [Member] 4 Properties Disposed Debt Instrument [Line Items] Debt Instrument [Line Items] Interest income Interest and Fee Income, Financing Receivable Capital in Excess of Par Value Additional Paid-in Capital [Member] Interest receivable Interest Receivable Name Trading Arrangement, Individual Name Cash and cash equivalents   Cash and cash equivalents Cash and Cash Equivalent Company Selected Measure Amount Company Selected Measure Amount Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Accounts and Financing Receivables [Table] Real Estate [Abstract] Real Estate [Abstract] Total NOI Consolidated net operating income (loss) Net Operating Income Net Operating Income from Continuing Operations Long-Term Debt [Roll Forward] Long-Term Debt [Roll Forward] Long-Term Debt [Roll Forward] Non-PEO NEO Non-PEO NEO [Member] Other Investors Other Investors [Member] Other Investors Proceeds from (payments on) interest rate swap settlements Derivative, Gain (Loss) On Settlement Derivative, Gain (Loss) On Settlement Property operating expenses Property operating expenses Total property operating expenses Cost of Product and Service Sold Award Timing Method Award Timing Method [Text Block] Increase (decrease) in cash, cash equivalents and restricted cash   Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation 2028 Exchangeable Notes 2028 Exchangeable Notes 2028 Exchangeable Notes [Member] 2028 Exchangeable Notes Total loans receivable, net of credit allowance Accounts and Financing Receivable, after Allowance for Credit Loss Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Debt exchanged or redeemed Debt Redeemed, Amount Debt Redeemed, Amount Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Proceeds from sales of real property   Cash proceeds from real estate dispositions Proceeds from Sale of Property, Plant, and Equipment Restatement Determination Date: Restatement Determination Date [Axis] Summary of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Consecutive trading days Debt Instrument, Convertible, Threshold Consecutive Trading Days Weighted average ownership percentage (in percent) Noncontrolling Interest, Weighted Average Ownership Percentage By Parent Noncontrolling Interest, Weighted Average Ownership Percentage By Parent Net operating income Net Operating Income [Member] Net Operating Income Summary of stockholder's equity capital accounts Class of Stock Disclosures [Abstract] Settlement of contractual agreements Business Combination, Consideration Transferred, Settlement of Contractual Agreements Business Combination, Consideration Transferred, Settlement of Contractual Agreements Debt Fund Seniors Housing Debt Fund ("Debt Fund"), [Member] Seniors Housing Debt Fund ("Debt Fund"), Revenues: Revenues: Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Equity and ATM Program issuances Gross Proceeds From Issuance Of Common Stock Gross proceeds from issuance of common stock. Statistical Measurement [Domain] Statistical Measurement [Domain] Document Fiscal Year Focus Document Fiscal Year Focus Common stock   Common Stock, Value, Issued Summary of Principal Activity Schedule of Long-Term Debt Instruments [Table Text Block] Restatement Determination Date Restatement Determination Date Investments in unconsolidated entities   Investments in unconsolidated entities Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Income tax benefit, change in valuation allowance Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount Property sold Disposal Group, Including Discontinued Operations, Number of Properties Sold Disposal Group, Including Discontinued Operations, Number of Properties Sold Allowance for credit losses on non-real estate loans receivable Accounts Receivable, Allowance for Credit Loss In place lease intangibles Leases, Acquired-in-Place [Member] Amendment Flag Amendment Flag Goodwill [Line Items] Goodwill [Line Items] Redemption of OP units and DownREIT units (in shares) Conversion of Stock, Shares Converted Genesis Healthcare Genesis Healthcare [Member] Genesis Healthcare Chartwell Joint Venture, Acquisition Transaction Chartwell Joint Venture, Acquisition Transaction [Member] Chartwell Joint Venture, Acquisition Transaction Less accumulated depreciation and amortization   Real Estate Investment Property, Accumulated Depreciation Disposal Group Classification [Axis] Disposal Group Classification [Axis] Other Equity Issuances (in shares) Stock Issued During Period, Shares, Other Shares issuable upon redemption (in shares) Redeemable Noncontrolling Interest, Equity, Shares Issuable Upon Redemption Redeemable Noncontrolling Interest, Equity, Shares Issuable Upon Redemption Stock incentive plans, net of forfeitures (in shares) Stock Issued During Period, Shares, Employee Stock Ownership Plan, Net Of Forfeiture Stock Issued During Period, Shares, Employee Stock Ownership Plan, Net Of Forfeiture LTIP Units - 10-Year ECAP Restricted Stock Units - Ten Year Program [Member] Restricted Stock Units - Ten Year Program Buildings and improvements Business Combination, Recognized Asset Acquired, Property, Plant, and Equipment, Building Held for sale Disposal Group, Held-for-Sale, Not Discontinued Operations [Member] Total net real estate assets Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Real Estate Assets Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Real Estate Assets Adjustment to Non-PEO NEO Compensation Footnote Adjustment to Non-PEO NEO Compensation Footnote [Text Block] Entity Address, State or Province Entity Address, State or Province PEO Total Compensation Amount PEO Total Compensation Amount Derivative, notional amount Derivative, Notional Amount Basic (in shares) Denominator for basic earnings per share - weighted average shares (in shares) Weighted Average Number of Shares Outstanding, Basic Secured debt Secured Debt Effect of foreign currency Financing Receivable, Allowance for Credit Loss, Foreign Currency Translation Collective loan pool Collective Loan Pool 4 [Member] Collective Loan Pool 4 [Member] Interest income Financing Receivable, Nonaccrual, Interest Income Consideration transferred Asset Acquisition, Consideration Transferred Land and land improvements   Land and Land Improvements Right of use assets, net Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Right-Of-Use Assets, Net Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Right-Of-Use Assets, Net Loans Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Document Information [Line Items] Document Information [Line Items] Award Timing MNPI Disclosure Award Timing MNPI Disclosure [Text Block] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Class of Stock [Axis] Class of Stock [Axis] Derivative and financial instruments designated as hedges gain (loss) Gain (loss) on derivative and financial instruments designated as hedges recognized in OCI Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments and Tax Net income (loss) attributable to common stockholders Numerator for basic earnings per share - net income (loss) attributable to common stockholders Net Income (Loss) Available to Common Stockholders, Basic Non-real estate loans Accounts Receivable, before Allowance for Credit Loss Receivable [Domain] Receivable [Domain] Accumulated amortization Intangible Asset, Finite-Lived, Accumulated Amortization Unsecured line of credit arrangement Line of Credit Facility, Maximum Borrowing Capacity Location, Statement of Other Comprehensive Income, Balance [Axis] Location, Statement of Other Comprehensive Income, Balance [Axis] Net other assets/(liabilities) disposed Gain (Loss) On Sale Of Other Assets And Liabilities Gain (Loss) On Sale Of Other Assets And Liabilities Rental income less than (in excess of) cash received   Straight Line Rent Number of outstanding credit obligations Number Of Outstanding Credit Obligations Number Of Outstanding Credit Obligations Treasury stock   Treasury Stock, Value New Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] Noncontrolling Interests Noncontrolling Interest [Member] Amortization of debt issuance costs Amortization of Debt Issuance Costs Senior unsecured notes Unsecured Debt [Member] Amounts related to stock incentive plans, net of forfeitures Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture, Net of Adjustments Shares Granted, Value, Share-Based Payment Arrangement, after Forfeiture, Net of Adjustments Total carrying value of debt Long-Term Debt Gain (loss) on real estate dispositions and acquisitions of controlling interests, net Gain (Loss) on Disposition of Real Estate and Asset Acquisitions, Net Of Adjustments Gain (Loss) on Disposition of Real Estate and Asset Acquisitions, Net Of Adjustments Net cash provided from (used in) investing activities   Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Equity Awards Adjustments, Excluding Value Reported in Compensation Table Equity Awards Adjustments, Excluding Value Reported in the Compensation Table [Member] Stockholders' Equity Equity [Text Block] Security Exchange Name Security Exchange Name Net change in noncontrolling interests Noncontrolling Interest, Period Increase (Decrease) Loan Carrying Value Financing Receivable, before Allowance for Credit Loss Repairs and maintenance Cost of Property Repairs and Maintenance Real property held for sale, net of accumulated depreciation   Real estate held-for-sale Real Estate, Held-for-Sale Number of common stock authorized for long-term incentive plan (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized Payments for hedge Payments for Hedge, Investing Activities Segment Reporting Segment Reporting, Policy [Policy Text Block] Finance leases Finance Lease, Right-of-Use Asset, after Accumulated Amortization HC-One Group Acquisition HC-One Group Acquisition [Member] HC-One Group Acquisition Name Outstanding Recovery, Individual Name Award Timing, How MNPI Considered Award Timing, How MNPI Considered [Text Block] Interest expense Interest expense Interest Expense, Borrowings Geographical [Domain] Geographical [Domain] Cumulative Dividends Accumulated Distributions [Member] Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year Prior Year End Fair Value of Equity Awards Granted in Any Prior Year that Fail to Meet Applicable Vesting Conditions During Covered Year [Member] Pension Adjustments Prior Service Cost Pension Adjustments Prior Service Cost [Member] Utilities Utilities Operating Expense Effect of dilutive securities: Weighted Average Number of Shares Outstanding, Diluted, Adjustment [Abstract] Ownership percentage by parent (in percent) Subsidiary, Ownership Percentage, Parent Total principal balance Beginning balance Ending balance Principal Long-Term Debt, Gross Compensation Amount Outstanding Recovery Compensation Amount Individual: Individual [Axis] Warrant Warrant [Member] Diluted (in shares) Denominator for diluted earnings per share - adjusted weighted average shares (in shares) Weighted Average Number of Shares Outstanding, Diluted Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Entity Emerging Growth Company Entity Emerging Growth Company Secured debt   Secured Debt, Excluding Private Placement Secured Debt, Excluding Private Placement Underlying Security Market Price Change Underlying Security Market Price Change, Percent Gross borrowings Proceeds from Lines of Credit Commercial paper note program Commercial Paper [Member] Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Right of use assets, net Total right of use assets, net Lease, Right-Of-Use Asset Lease, Right-Of-Use Asset Mortgage loans Mortgage Receivable [Member] Operating lease, liability, statement of financial position [extensible list] Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration] Average Price Sale Of Stock Price Per Share [Abstract] Sale Of Stock Price Per Share [Abstract] Cash disbursed for capital improvements to existing properties Capital improvements to existing properties Payments for Capital Improvements Treasury Stock Treasury Stock, Common [Member] Intangible Asset, Goodwill and Other [Abstract] Intangible Asset, Goodwill and Other [Abstract] Letters of credit outstanding Letters of Credit Outstanding, Amount Payments to extinguish, exchange or redeem senior unsecured notes   Repayments of Unsecured Debt Net proceeds from issuance of senior unsecured notes Proceeds from Issuance of Unsecured Debt Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Derivative asset Derivative Asset, Notional Amount Collateral Held [Domain] Collateral Held [Domain] All Executive Categories All Executive Categories [Member] Pension Adjustments Service Cost Pension Adjustments Service Cost [Member] 39 Properties Disposed 39 Properties Disposed [Member] 39 Properties Disposed Weighted average number of common shares outstanding: Average number of common shares outstanding [Abstract] Average number of common shares outstanding Asset Acquisition [Domain] Asset Acquisition [Domain] Exchangeable notes (in shares) Incremental Common Shares Attributable to Dilutive Effect of Exchangeable Notes Incremental Common Shares Attributable to Dilutive Effect of Exchangeable Notes Outpatient Medical Portfolio Disposition Outpatient Medical Portfolio Disposition [Member] Outpatient Medical Portfolio Disposition Fair Value, Separate Account Investment [Line Items] Fair Value, Separate Account Investment [Line Items] Summary of Computation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Segment Reporting Segment Reporting [Text Block] Minimum Minimum [Member] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Liabilities:   Liabilities [Abstract] Sales type lease income Sales-type Lease, Lease Income Summary of Real Estate Intangible Amortization Income (Expense) Intangible Asset, Finite-Lived, Amortization Expense [Table Text Block] Effect of foreign currency translation on cash and cash equivalents and restricted cash Effect of Exchange Rate on Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Income Statement Location [Axis] Location, Statement of Income, Balance [Axis] Income (loss) from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Income (loss) from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share Non-Rule 10b5-1 Arrangement Adopted Non-Rule 10b5-1 Arrangement Adopted [Flag] Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table Aggregate Grant Date Fair Value of Equity Award Amounts Reported in Summary Compensation Table [Member] Common Stock, $1.00 par value: Common Stock, Number of Shares, Par Value and Other Disclosure [Abstract] Business Combination [Line Items] Business Combination [Line Items] Authorized shares (in shares) Common Stock, Shares Authorized Financing Receivable, Allowance for Credit Loss [Table] Financing Receivable, Allowance for Credit Loss [Table] Net real property owned   Real Estate Investment Property, Net Summary of accumulated other comprehensive income/(loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Credit Concentration Concentration Risk Disclosure [Text Block] ATM Program issuances (in shares) Equity and ATM Program Issuance (in shares) Sale of Stock, Number of Shares Issued in Transaction Cogir Senior Living Cogir Senior Living [Member] Cogir Senior Living Exercise Price Award Exercise Price Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Segment Reporting [Line Items] Segment Reporting [Line Items] Fair Value, Separate Account Investment [Table] Fair Value, Separate Account Investment [Table] Document Quarterly Report Document Quarterly Report Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested Year-over-Year Change in Fair Value of Equity Awards Granted in Prior Years That are Outstanding and Unvested [Member] Barchester Healthcare Acquisition Barchester Healthcare Acquisition [Member] Barchester Healthcare Acquisition Canadian Dollar Denominated Senior Unsecured Notes Due 2031 3.850% Senior Unsecured Notes Due 2031 [Member] 3.850% Senior Unsecured Notes Due 2031 Non-real estate loans receivable, net of credit allowance Accounts Receivable, after Allowance for Credit Loss Income (loss) from continuing operations before income taxes and other items Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Management fees Management Fee Expense Awards Close in Time to MNPI Disclosures, Table Awards Close in Time to MNPI Disclosures [Table Text Block] Equity method investments Equity Method Investments Real Property Acquisitions and Development Real Estate Disclosure [Text Block] Equity Component [Domain] Equity Component [Domain] Property taxes Real Estate Tax Expense Loans receivable, fair value Loans Receivable, Fair Value Disclosure Adoption Date Trading Arrangement Adoption Date Total Proceeds from Issuance or Sale of Equity Consideration Disposal Group, Including Discontinued Operation, Consideration Counterparty Name [Domain] Counterparty Name [Domain] Net investment hedges Notional Amount of Nonderivative Instruments Title Trading Arrangement, Individual Title Forgone Recovery due to Disqualification of Tax Benefits, Amount Forgone Recovery due to Disqualification of Tax Benefits, Amount Accounting Policies [Abstract] Accounting Policies [Abstract] Restatement does not require Recovery Restatement Does Not Require Recovery [Text Block] Operating leases Operating Lease, Liability Financing leases Finance Lease, Liability Other financing activities Proceeds from (Payment for) Other Financing Activity Insider Trading Policies and Procedures Adopted Insider Trading Policies and Procedures Adopted [Flag] Schedule of Aggregate Borrowings Under Unsecured Revolving Credit Facility and Commercial Paper Program Schedule of Line of Credit Facilities [Table Text Block] Cash disbursed for construction in progress Cash disbursed for construction in progress Payments for Construction in Process General and administrative expenses General and administrative expenses Selling, General and Administrative Expense Business Combination [Domain] Business Combination [Domain] Amortization related to in-place lease intangibles and lease commissions Depreciation Amortization Related to in Place Lease Intangibles and Lease Commissions Depreciation and amortization related to in place lease intangibles and lease commissions Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Compensation Actually Paid vs. Net Income Compensation Actually Paid vs. Net Income [Text Block] Rental income   Operating Lease, Lease Income Restricted stock units Restricted Stock Units (RSUs) [Member] All Adjustments to Compensation All Adjustments to Compensation [Member] Corporate Non-segment/Corporate Segment Reporting, Reconciling Item, Corporate Nonsegment [Member] Amica Senior Lifestyles Acquisition, Forward Purchase Agreement Amica Senior Lifestyles Acquisition, Forward Purchase Agreement [Member] Amica Senior Lifestyles Acquisition, Forward Purchase Agreement Business Combination [Axis] Business Combination [Axis] Net cash provided from (used in) operating activities   Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Sales type lease, number of properties Sales Type Lease, Number of Properties Sales Type Lease, Number of Properties Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Investments in sales-type leases, net Sales-Type Lease, Net Investment in Lease, after Allowance for Credit Loss Gross Proceeds Proceeds From Issuance Or Sale Of Equity Gross [Abstract] Proceeds From Issuance Or Sale Of Equity Gross [Abstract] Finance lease, liability, statement of financial position [extensible list] Finance Lease, Liability, Statement of Financial Position [Extensible Enumeration] Expenses: Operating Expenses [Abstract] Stock Appreciation Rights (SARs) Stock Appreciation Rights (SARs) [Member] Net income attributable to common stockholders (pro forma) (in USD per share) Business Combination, Pro Forma Information, Pro Forma Earnings Per Share, Diluted Buildings and improvements   Investment Building and Building Improvements Denominated in U.S. Dollars United States of America, Dollars Other Commitments [Domain] Other Commitments [Domain] City Area Code City Area Code Geographic Concentration Risk Geographic Concentration Risk [Member] Document Information [Table] Document Information [Table] Secured debt Debt Instrument, Fair Value Disclosure Accumulated amortization Below Market Lease, Accumulated Amortization Name Forgone Recovery, Individual Name Receivables and other assets   Receivables and other assets Receivables And Other Assets Receivables And Other Assets Non-GAAP Measure Description Non-GAAP Measure Description [Text Block] Entity [Domain] Entity [Domain] Issued shares (in shares) Preferred Stock, Shares Issued UK Debt Due 2028 UK Debt Due 2028 [Member] UK Debt Due 2028 Issued in November 20, 2013. 4.25% Senior Unsecured Notes 4.25% Senior Unsecured Notes [Member] 4.25% Senior Unsecured Notes Decrease (increase) in receivables and other assets   Increase (Decrease) in Other Operating Assets Put-Call Agreements Put-Call Agreements [Member] Put-Call Agreements Business Nature of Operations [Text Block] 2.750% Senior Unsecured Notes Due 2028 2.750% Senior Unsecured Notes Due 2028 [Member] 2.750% Senior Unsecured Notes Due 2028 Seniors Housing Operating Seniors Housing Operating Senior Housing - Operating [Member] Senior Housing - Operating [Member]. Food Food Expense Food Expense Total compensation expense Share-Based Payment Arrangement, Expense Measurement Basis [Axis] Measurement Basis [Axis] Chartwell Joint Venture, Disposal Transaction Chartwell Joint Venture, Disposal Transaction [Member] Chartwell Joint Venture, Disposal Transaction Number of additional shares authorized (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Additional Shares Authorized Option exercises (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Exercises in Period Acquisition measurement period adjustments Goodwill, Acquired During Period Subsequent Event Type [Domain] Subsequent Event Type [Domain] Assets: Intangible Asset, Excluding Goodwill, after Accumulated Amortization [Abstract] Erroneously Awarded Compensation Recovery Erroneously Awarded Compensation Recovery [Table] Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Entity Current Reporting Status Entity Current Reporting Status Net cash provided from (used in) financing activities   Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Unsecured Debt [Table] Unsecured Debt [Table] Unsecured Debt Accruals Accruals Accruals Cash Flow Hedging Cash Flow Hedging [Member] Cash disbursed for acquisitions Payments to Acquire Real Estate Summary of Items Measured at Fair Value on Recurring Basis, Liabilities Fair Value, Liabilities Measured on Recurring Basis [Table Text Block] 4.50% Senior Unsecured Notes Due 2034 4.50% Senior Unsecured Notes Due 2034 [Member] 4.50% Senior Unsecured Notes Due 2034 Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Summary of Business Combination, Pro Forma Information Business Combination, Pro Forma Information [Table Text Block] Adjustments to reconcile net income (loss) to net cash provided from (used in) operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] 2029 Long-Term Debt, Maturity, Year Three Collective loan pool Collective Loan Pool 5 [Member] Collective Loan Pool 5 [Member] Financing activities:   Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Guarantee of 4.500% Notes due 2034 issued by Welltower OP LLC Guarantee Notes Due 2034 4.500% [Member] Guarantee Notes Due 2034 4.500% Contributions to unconsolidated entities   Payments to Acquire Interest in Joint Venture Financial Instruments [Domain] Financial Instruments [Domain] Expected sale proceeds Proceeds from Sale, Property, Held-for-Sale Other income Other Income Intangible Asset, Finite-Lived, Class [Axis] Intangible Asset, Finite-Lived, Class [Axis] Intangible Assets and Goodwill Intangible Asset and Goodwill [Text Block] Underlying Securities Award Underlying Securities Amount Less: Total comprehensive income (loss) attributable to noncontrolling interests Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Fair Value Estimate of Fair Value Measurement [Member] Net proceeds from issuance of common stock Stock Issued During Period, Value, New Issues Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Assets Assets, Total [Member] Foreign currency forward contracts, interest rate swaps and cross currency swaps Foreign currency forward contracts, interest rate swaps and cross currency swaps, net asset (liability) Foreign Currency Contracts, Liability, Fair Value Disclosure Segment Concentration Risk Segment Concentration Risk [Member] Segment Concentration Risk Other investments, net of payments   Payment for (Proceeds from) Other Investing Activity Principal payments Debt Instrument, Periodic Payment, Principal 30 Properties Disposed 30 Properties Disposed [Member] 30 Properties Disposed Number of available for grant (in shares) Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant Segment Reporting [Table] Segment Reporting [Table] Canadian Dollar Denominated Senior Unsecured Notes Due 2033 4.150% Senior Unsecured Notes Due 2033 [Member] 4.150% Senior Unsecured Notes Due 2033 Pro forma Business Combination, Acquiree's Revenue since Acquisition Date, Actual Summary of Components of Lease Expense Lease, Cost [Table Text Block] Lease liabilities: Liabilities, Lessee [Abstract] Liabilities, Lessee [Abstract] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] All Trading Arrangements All Trading Arrangements [Member] Other Performance Measure, Amount Other Performance Measure, Amount Award Timing MNPI Considered Award Timing MNPI Considered [Flag] Current Fiscal Year End Date Current Fiscal Year End Date Non-PEO NEO Average Total Compensation Amount Non-PEO NEO Average Total Compensation Amount Derivative [Line Items] Derivative [Line Items] Investments in sales-type leases, net Sales-Type Lease, Net Investment in Lease, Fair Value Disclosure Sales-Type Lease, Net Investment in Lease, Fair Value Disclosure Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year Change in Fair Value as of Vesting Date of Prior Year Equity Awards Vested in Covered Year [Member] Dividends declared and paid per common share (in dollars per share) Dividends (in dollars per share) Common stock (in dollars per share) Common Stock, Dividends, Per Share, Declared Entity File Number Entity File Number Recovery of Erroneously Awarded Compensation Disclosure [Line Items] Senior loans Senior Notes Measure: Measure [Axis] Investments in Unconsolidated Entities Equity Method Investments and Joint Ventures Disclosure [Text Block] Summary of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Net proceeds from net investment hedge settlements Payments for (Proceeds from) Hedge, Investing Activities Equity Components [Axis] Equity Components [Axis] Income taxes paid (received), net Income Tax Paid, after Refund Received Entity Interactive Data Current Entity Interactive Data Current Less: Net income (loss) attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Option exercises Stock Issued During Period Gross Proceeds Stock Options Exercised Stock issued during period gross proceeds stock options exercised. Entity Small Business Entity Small Business Total comprehensive income (loss) attributable to common stockholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Sales-Type Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration] Sales-Type Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration] Useful life Intangible Asset, Finite-Lived, Acquired, Weighted-Average Amortization Period Accordion feature Accordion Feature [Member] An option that gives the right to increase its line of credit or similar type of liability with a lender. Care UK Care UK [Member] Care UK MNPI Disclosure Timed for Compensation Value MNPI Disclosure Timed for Compensation Value [Flag] 2029 Exchangeable Notes 2029 Exchangeable Notes [Member] 2029 Exchangeable Notes Document Type Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Loss (gain) on extinguishment of debt, net Loss (gain) on extinguishment of debt, net   Gain (Loss) on Extinguishment of Debt Real estate dispositions Real property dispositions [Abstract] Real property dispositions. Accounting Policies and Related Matters Significant Accounting Policies [Text Block] Foreign currency translation gain (loss) Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Local Phone Number Local Phone Number Canada CANADA Authorized amount to sell Sale Of Stock, Authorized Amount Sale Of Stock, Authorized Amount Seniors Housing Triple-net Acquisition Seniors Housing Triple-net Acquisition [Member] Seniors Housing Triple-net Acquisition Net Investment Hedging Net Investment Hedging [Member] Changed Peer Group, Footnote Changed Peer Group, Footnote [Text Block] Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward] Equity, Attributable to Noncontrolling Interest [Roll Forward] Total comprehensive income Comprehensive Income Excluding Redeemable Noncontrolling Interest Comprehensive Income Excluding Redeemable Noncontrolling Interest. Executive Category: Executive Category [Axis] Receivable Type [Axis] Receivable Type [Axis] Counterparty Name [Axis] Counterparty Name [Axis] Liabilities and equity   Liabilities and equity: Liabilities and Equity [Abstract] Other Commitments [Table] Other Commitments [Table] Non-PEO NEO Average Compensation Actually Paid Amount Non-PEO NEO Average Compensation Actually Paid Amount Mint UK Bidco LLC, Properties Subject to Triple Net Lease Mint UK Bidco LLC, Properties Subject to Triple Net Lease [Member] Mint UK Bidco LLC, Properties Subject to Triple Net Lease Schedule of Variable Interest Entities [Table] Variable Interest Entity [Table] Equity issued in acquisition Asset Acquisition, Consideration Transferred, Equity Interest Issued and Issuable Supplemental cash flow information: Supplemental Cash Flow Information [Abstract] Amortization related to above (below) market leases, net   Amortization of above and below Market Leases PEO Name PEO Name Accrued expenses and other liabilities   Accrued expenses and other liabilities Accrued Liabilities and Other Liabilities Derivative and financial instruments designated as hedges Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member] Financial liabilities: Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Net real estate investments   Net real estate investments Real Estate Investments, Net Cash acquired from acquisition Cash Acquired from Acquisition Payments on secured debt   Repayments of Secured Debt Stock Price or TSR Estimation Method Stock Price or TSR Estimation Method [Text Block] Entity Tax Identification Number Entity Tax Identification Number Other Commitments [Line Items] Other Commitments [Line Items] Summary of Credit Concentration Fair Value, Concentration of Risk [Table Text Block] Construction in progress additions Construction in Process, Additions Construction in Process, Additions Adjustment to members’ interest from change in ownership in Welltower OP Adjustment To Members Interest From Change In Ownership From The OP Adjustment To Members Interest From Change In Ownership From The OP Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Thereafter Long Term Debt, Maturity, After Year Four Long Term Debt, Maturity, After Year Four Effect of foreign currency Effect of foreign currency Foreign Currency Gain (Loss) On Debt Foreign Currency Gain (Loss) On Debt Aggregate Erroneous Compensation Not Yet Determined Aggregate Erroneous Compensation Not Yet Determined [Text Block] Material Terms of Trading Arrangement Material Terms of Trading Arrangement [Text Block] Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year Vesting Date Fair Value of Equity Awards Granted and Vested in Covered Year [Member] Total comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Stock-based compensation expense   Share-Based Payment Arrangement, Noncash Expense Compensation Labor and Related Expense Total Lease, Cost Capitalized interest   Interest Paid, Capitalized, Investing Activity Disposal Group Name [Axis] Disposal Group Name [Axis] Income (loss) from real estate dispositions, net Disposal Group, Including Discontinued Operation, Operating Income (Loss) Collective loan pool Collective Loan Pool 2 [Member] Collective Loan Pool 2 [Member] Net income (loss) attributable to common stockholders (in dollars per share) Basic earnings per share (in dollars per share) Earnings Per Share, Basic Insider Trading Arrangements [Line Items] Right of use assets: Assets, Lessee [Abstract] Assets, Lessee [Abstract] Payments for deferred financing costs and prepayment penalties   Payments of Financing Costs Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table Aggregate Change in Present Value of Accumulated Benefit for All Pension Plans Reported in Summary Compensation Table [Member] Remaining portfolio Remaining Portfolio [Member] Remaining portfolio. Fair Value Measurement [Domain] Fair Value Measurement [Domain] Compensation Actually Paid vs. Company Selected Measure Compensation Actually Paid vs. Company Selected Measure [Text Block] Cover [Abstract] Cover [Abstract] Summary of Real Estate Loan Activity Summary Of Real Estate Loan Activity [Table Text Block] Summary of real estate loan activity. Sold or Held for sale Disposal Group, Held-for-Sale or Disposed of by Sale, Not Discontinued Operations [Member] United Kingdom UNITED KINGDOM Collective loan pool Collective Loan Pool 3 [Member] Collective Loan Pool 3 [Member] Percent of NOI Percentage Concentration Risk, Percentage Equity Awards Adjustments Equity Awards Adjustments [Member] Hedging Relationship [Domain] Hedging Relationship [Domain] Chartwell Joint Venture Chartwell Joint Venture [Member] Chartwell Joint Venture Increase (decrease) in accrued expenses and other liabilities   Increase (Decrease) in Other Operating Liabilities Senior Unsecured Notes and Secured Debt Long-Term Debt [Text Block] Other Financial Obligations Other Debt Obligations [Member] Net Proceeds Proceeds from Issuance or Sale of Equity [Abstract] Equity:   Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Authorized shares (in shares) Preferred Stock, Shares Authorized Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Provision for loan losses, net Financing Receivable, Credit Loss, Expense (Reversal), Net Of Adjustments Financing Receivable, Credit Loss, Expense (Reversal), Net Of Adjustments Number of properties Number of Properties Number of Real Estate Properties Hedging Designation [Domain] Hedging Designation [Domain] Class of Stock [Domain] Class of Stock [Domain] Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Other commitment Other Commitment Below market tenant leases Below Market Lease, Gross Preferred Stock, $1.00 par value: Preferred Stock, Number of Shares, Par Value and Other Disclosure [Abstract] Investments in unconsolidated entities Real Estate Investments, Joint Ventures Properties classified as held for sale Number Of Properties Classified As Held For Sale This represents the number of the properties which are classified as held for sale. Mint UK Bidco LLC, Properties Under RIDEA Structure Mint UK Bidco LLC, Properties Under RIDEA Structure [Member] Mint UK Bidco LLC, Properties Under RIDEA Structure Summary of Stockholders' Equity Capital Accounts Schedule of Stock by Class [Table Text Block] Aggregate Available Trading Arrangement, Securities Aggregate Available Amount Discontinued Operations and Disposal Groups [Abstract] Discontinued Operations and Disposal Groups [Abstract] Income Taxes And Distributions Income Tax Disclosure [Text Block] Pay vs Performance Disclosure Pay vs Performance Disclosure [Table] Business combination, consideration transferred Business Combination, Consideration Transferred Entity Filer Category Entity Filer Category Expected consideration Asset Acquisition, Price of Acquisition, Expected Canadian Dollar Denominated Senior Unsecured Notes Due 2026 Canadian Dollar Denominated Senior Unsecured Notes [Member] Canadian Dollar Denominated Senior Unsecured Notes Principal payments due on debt obligations Long-Term Debt, Fiscal Year Maturity [Abstract] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Distributions by unconsolidated entities Proceeds from Equity Method Investment, Distribution Derivative Instruments Not Designated Not Designated as Hedging Instrument [Member] Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Net book value Below Market Lease, Net Schedule of Stock by Class [Table] Stock, Class of Stock [Table] Net income (loss) Net income (loss) Net income (loss)  Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Derivative liability Derivative Liability Pro forma revenues Business Combination, Pro Forma Information, Pro Forma Revenue Entity Address, Address Line One Entity Address, Address Line One Income tax (expense) benefit Income tax (expense) benefit Income Tax Expense (Benefit) Fair Value Hedging Fair Value Hedging [Member] Risks and Uncertainties [Abstract] Risks and Uncertainties [Abstract] Collective loan pool Collective Loan Pool 6 [Member] Collective Loan Pool 6 Triple-net Triple Net [Member] Triple Net [Member]. Unsecured Debt [Line Items] Unsecured Debt [Line Items] Unsecured Debt [Line Items] Property acquired Asset Acquisition, Number Of Properties Acquired Asset Acquisition, Number Of Properties Acquired VIE, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Real estate and Corporate Operating Segments And Corporate Non-Segment [Member] Operating Segments And Corporate Non-Segment [Member] Unamortized debt issuance costs, net Less: unamortized debt issuance costs Unamortized Debt Issuance Expense Amica Senior Lifestyles, Unconsolidated Properties Amica Senior Lifestyles, Unconsolidated Properties [Member] Amica Senior Lifestyles, Unconsolidated Properties Principal collected on loans receivable   Less: Receipts on loans receivable Proceeds from Collection of Loans Receivable Statement [Table] Statement [Table] Option exercises Proceeds from Stock Options Exercised Summary of Real Estate Intangibles Excluding Those Related to Ground Lease or Classified as Held For Sale Schedule Of Real Estate Intangibles Excluding Held For Sale [Table Text Block] Schedule of real estate intangibles excluding held for sale. Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]