Debt Instrument, Maximum Borrowing Capacity

No definition available.

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Namespace Prefix:	csr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument Number Of Extensions

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Term, Extensions

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Additional Borrowing Capacity

+ References

No definition available.

+ Details

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Namespace Prefix:	csr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Refers to number of loans in default

+ References

No definition available.

+ Details

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Namespace Prefix:	csr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Real Estate Properties, Collateral

+ References

No definition available.

+ Details

Name:	csr_NumberOfRealEstatePropertiesCollateral
Namespace Prefix:	csr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Number Of Real Estate Properties, Unencumbered

+ References

No definition available.

+ Details

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Namespace Prefix:	csr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The effective interest rate during the reporting period.

+ References

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+ Details

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MortgagesMember
Namespace Prefix:
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Balance Type:
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- Details

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Balance Type:
Period Type:

- Details

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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=csr_NotePurchaseAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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- Details

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- Details

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DEBT - Narrative (Details)	9 Months Ended	12 Months Ended
DEBT - Narrative (Details)	Sep. 30, 2026 USD ($) loan apartmentCommunity extensionOption	Dec. 31, 2025 USD ($) apartmentCommunity	Aug. 31, 2026 USD ($)	May 31, 2025 USD ($)	Apr. 30, 2025 USD ($)	Oct. 28, 2024 USD ($)
Line of Credit Facility [Line Items]
Number of real estate properties, unencumbered by mortgages \| apartmentCommunity	31
Revolving lines of credit	$ 0	$ 154,925,000
Carrying principal value	$ 843,819,000	$ 1,053,909,000
Weighted average interest rate	3.37%	3.64%
Mortgages
Line of Credit Facility [Line Items]
Carrying principal value	$ 345,000,000.0	$ 400,100,000
Number of real estate properties, serving as collateral for mortgage loans \| apartmentCommunity	9	10
Number of loans in default \| loan	0
Private Shelf Agreement \| Unsecured Senior Notes
Line of Credit Facility [Line Items]
Carrying principal value	$ 175,000,000.0
Maximum borrowing capacity						$ 300,000,000.0
Note Purchase Agreement \| Unsecured Senior Notes
Line of Credit Facility [Line Items]
Debt instrument, face amount	125,000,000.0
Fannie Mae Credit Facility Agreement \| Mortgages
Line of Credit Facility [Line Items]
Carrying principal value	198,850,000	$ 198,850,000
Debt instrument, face amount	$ 198,900,000
Number of real estate properties, serving as collateral for mortgage loans \| apartmentCommunity	7
Weighted average interest rate	2.78%	2.78%
Line of Credit \| BMO Line of Credit
Line of Credit Facility [Line Items]
Accordion option				$ 150,000,000.0
Maximum borrowing capacity			$ 250,000,000.0	$ 400,000,000.0	$ 250,000,000.0
Remaining borrowing capacity	$ 250,000,000.0	$ 246,000,000.0
Revolving lines of credit	$ 0	$ 154,000,000.0
Operating line of credit, interest rate		5.12%
Number of extensions \| extensionOption	2
Debt extension term	6 months
Line of Credit \| BMO Line of Credit \| Minimum \| Base Rate
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)	0.20%
Line of Credit \| BMO Line of Credit \| Minimum \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)	1.20%
Line of Credit \| BMO Line of Credit \| Maximum \| Base Rate
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)	0.80%
Line of Credit \| BMO Line of Credit \| Maximum \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)	1.80%
Operating Line of Credit \| US Bank NA
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 10,000,000.0
Revolving lines of credit	$ 0	$ 925,000
Operating line of credit, interest rate		5.91%