Balance Sheets [Abstract] Net utility plant Total current assets Total other long-term assets Total Assets Total common stockholders' equity Balance Balance Total current liabilities Total deferred credits Total Stockholders' Equity and Liabilities Statements of Income [Abstract] Operating expenses Operating income Other income (expenses) Income before income taxes Net Income Net income Net income (in Dollars) Statements of Common Stockholders’ Equity [Abstract] Balance (in Shares) Balance (in Shares) Common stock, outstanding (in Shares) Equity Components [Axis] Statements of Cash Flows [Abstract] Net cash provided by operating activities Net cash used in investing activities Net cash provided by financing activities Net change in cash and cash equivalents Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Basis of Presentation [Abstract] Acquisitions [Abstract] Accounts Receivable and Unbilled Revenue [Abstract] Accounts receivable Change in accounts receivable Accounts receivable, net Change in accounts receivable, net Common Stock and Earnings Per Share [Abstract] Weighted average common shares, diluted (in Shares) Debt [Abstract] Debt Instrument [Axis] Statistical Measurement [Axis] Interest Rate Swap Agreement [Abstract] Fair Value of Financial Instruments [Abstract] Measurement Frequency [Axis] Fair Value Hierarchy and NAV [Axis] Commitments [Abstract] Revenue Recognition [Abstract] Customer [Axis] Product and Service [Axis] Total operating revenue OPERATING REVENUES: Rate Matters [Abstract] Pensions [Abstract] Net periodic pension cost Retirement Plan Type [Axis] Stock-Based Compensation [Abstract] Nonvested at beginning of the period Nonvested at end of the period Nonvested at beginning of the period (in Dollars per share) Nonvested at end of the period (in Dollars per share) Award Type [Axis] Plan Name [Axis] Income Taxes [Abstract] Document Type Document Quarterly Report Document Period End Date Document Fiscal Year Focus Document Transition Report Entity File Number Entity Registrant Name Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Entity Central Index Key Amendment Flag Document Fiscal Period Focus Current Fiscal Year End Date ASSETS UTILITY PLANT, at original cost Plant acquisition adjustments Acquisition adjustment OTHER PHYSICAL PROPERTY, net of accumulated depreciation of $590 in 2026 and $573 in 2025 Other physical property, accumulated depreciation CURRENT ASSETS: Cash and cash equivalents Accounts receivable, net of reserves of $1,860 in 2026 and $1,710 in 2025 Accounts receivables, reserves Less: allowance for doubtful accounts Unbilled revenues Recoverable income taxes Materials and supplies inventories, at cost Prepaid expenses OTHER LONG-TERM ASSETS: Prepaid pension cost Note receivable Deferred regulatory assets Other assets STOCKHOLDERS' EQUITY AND LIABILITIES COMMON STOCKHOLDERS' EQUITY: Common stock, no par value, authorized 46,500,000 shares, issued and outstanding 16,227,737 shares in 2026 and 14,446,581 shares in 2025 Common stock, par value (in Dollars per share) Common stock, authorized (in Shares) Common stock, issued (in Shares) Retained earnings PREFERRED STOCK, authorized 500,000 shares, no shares issued Preferred stock, authorized (in Shares) Preferred stock, issued (in Shares) LONG-TERM DEBT Long-term portion COMMITMENTS CURRENT LIABILITIES: Short-term borrowings Current portion of long-term debt Less current maturities Accounts payable Dividends payable Accrued compensation and benefits Accrued interest Deferred regulatory liabilities Other accrued expenses DEFERRED CREDITS: Customers' advances for construction Deferred income taxes Deferred employee benefits Deferred regulatory liabilities Other deferred credits Contributions in aid of construction OPERATING EXPENSES: Operation and maintenance Administrative and general Depreciation and amortization Taxes other than income taxes OTHER INCOME (EXPENSES): Allowance for funds used during construction Other income (expenses), net Income tax expense (benefit) Basic Earnings Per Share (in Dollars per share) Diluted Earnings Per Share (in Dollars per share) Cash dividends declared (in Dollars per share) Issuance of common stock Issuance of common stock (in Shares) Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans Issuance of common stock under dividend reinvestment, direct stock and employee stock purchase plans (in Shares) Stock-based compensation Stock-based compensation (in Shares) CASH FLOWS FROM OPERATING ACTIVITIES: Adjustments to reconcile net income to net cash provided by operating activities: Depreciation and amortization Stock-based compensation Decrease in deferred income taxes Changes in assets and liabilities: Increase in accounts payable, accrued compensation and benefits, other accrued expenses, deferred employee benefits, deferred regulatory liabilities, and other deferred credits Decrease in accrued interest CASH FLOWS FROM INVESTING ACTIVITIES: Utility plant additions, debt portion of allowance for funds used during construction Decrease in note receivable Cash received from surrender of life insurance policies CASH FLOWS FROM FINANCING ACTIVITIES: Customers' advances for construction and contributions in aid of construction Proceeds of long-term debt issues Changes in cash overdraft position Issuance of common stock Supplemental disclosures of cash flow information: Cash paid during the period for: Interest, net of amounts capitalized Income taxes Supplemental disclosure of non-cash investing and financing activities: Accounts payable includes $6,386 in 2026 and $5,016 in 2025 for the construction of utility plant. Accounts payable for construction of utility plant Accumulated depreciation Interest on debt Other pension costs Cash dividends declared Other Increase in accounts receivable and unbilled revenues Increase in recoverable income taxes Increase in materials and supplies inventories, prepaid expenses, prepaid pension cost, deferred regulatory and other assets Utility plant additions, including debt portion of allowance for funds used during construction of $339 in 2026 and $210 in 2025 Acquisitions of wastewater systems Purchase price and acquisition costs Repayments of customer advances Repayments of long-term debt Repayments under short-term agreements Dividends paid Common Stock [Member] Retained Earnings [Member] Basis of Presentation Acquisitions Accounts Receivable and Unbilled Revenue