Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Property, Plant and Equipment
Regulated Energy	$ 2,789,200	$ 2,661,800
Unregulated Energy	482,200	463,700
Other Businesses and Eliminations	37,700	29,900
Total property, plant and equipment	3,309,100	3,155,400
Less: Accumulated depreciation and amortization	(600,300)	(567,600)
Property, Plant and Equipment, Net	2,908,000	2,735,900
Current Assets
Cash and cash equivalents	1,500	7,900
Trade and other receivables	84,100	76,700
Accounts Receivable, Allowance for Credit Loss, Current	(4,962)	(3,291)
Accounts Receivable, before Allowance for Credit Loss, Current	89,100	80,000
Accrued revenue	26,900	37,800
Propane inventory, at average cost	6,700	8,900
Other inventory, at average cost	18,400	18,000
Regulatory assets	20,800	23,900
Storage gas prepayments	3,600	3,800
Income taxes receivable	10,700	6,800
Prepaid expenses	16,400	17,300
Derivative assets, at fair value	300	600
Other current assets	2,900	2,600
Total current assets	192,300	204,300
Deferred Charges and Other Assets
Goodwill	507,700	507,700
Other intangible assets, net	14,000	15,000
Investments, at fair value	15,900	14,400
Operating Lease, Right-of-Use Asset	9,600	10,500
Regulatory assets	76,100	77,400
Receivables and other deferred charges	14,100	11,700
Total deferred charges and other assets	637,500	636,800
Total Assets	3,737,800	3,577,000
Stockholders’ equity
Preferred stock, par value $0.01 per share (authorized 2,000,000 shares), no shares issued and outstanding	0	0
Common stock, par value $0.4867 per share (authorized 50,000,000 shares)	11,400	11,100
Additional paid-in capital	896,400	830,500
Retained earnings	594,100	550,300
Accumulated other comprehensive loss	(2,800)	(1,700)
Deferred compensation obligation	12,500	9,800
Treasury stock	(12,500)	(9,800)
Total stockholders’ equity	1,499,100	1,390,200
Total capitalization	2,748,700	2,651,900
Current Liabilities
Less: current maturities	25,500	25,500
Short-term borrowing	245,300	196,500
Accounts payable	69,100	78,300
Customer deposits and refunds	48,100	45,700
Accrued interest	4,900	4,800
Dividends payable	16,000	14,700
Accrued compensation	12,200	23,900
Regulatory liabilities	16,100	16,100
Derivative liabilities, at fair value	200	0
Other accrued liabilities	22,400	13,900
Total current liabilities	459,800	419,400
Deferred Credits and Other Liabilities
Deferred income taxes	315,700	296,100
Regulatory liabilities	185,900	184,000
Environmental liabilities	2,800	2,200
Other pension and benefit costs	14,300	13,200
Operating Lease, Liability, Noncurrent	8,000	8,700
Deferred investment tax credits and other liabilities	1,400	1,400
Total deferred credits and other liabilities	529,300	505,700
Total Capitalization and Liabilities	3,737,800	3,577,000
Other Businesses and Eliminations	37,700	29,900
Property, Plant and Equipment, Gross	3,309,100	3,155,400
Construction Work in Progress	199,200	148,100
Property, Plant and Equipment, Net	2,908,000	2,735,900
Trade and other receivables	84,100	76,700
Income taxes receivable	10,700	6,800
Other current assets	2,900	2,600
Assets, Current	192,300	204,300
Receivables and other deferred charges	14,100	11,700
Deferred Charges And Other Assets	637,500	636,800
Total identifiable assets	3,737,800	3,577,000
Regulated Energy	2,789,200	2,661,800
Unregulated Energy	482,200	463,700
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	600,300	567,600
Cash and cash equivalents	1,500	7,900
Accounts Receivable, before Allowance for Credit Loss, Current	89,100	80,000
Allowance for uncollectible accounts	4,962	3,291
Accrued revenue	26,900	37,800
Propane inventory, at average cost	6,700	8,900
Other inventory, at average cost	18,400	18,000
Regulatory assets	20,800	23,900
Storage gas prepayments	3,600	3,800
Prepaid expenses	16,400	17,300
Derivative assets, at fair value	300	600
Goodwill	507,700	507,700
Other intangible assets, net	14,000	15,000
Investments, at fair value	15,900	14,400
Operating Lease, Right-of-Use Asset	9,600	10,500
Regulatory assets	76,100	77,400
Preferred stock, par value $0.01 per share (authorized 2,000,000 shares), no shares issued and outstanding	0	0
Stockholders' Equity Attributable to Parent	1,499,100	1,390,200
Capitalization, Long-term Debt and Equity	2,748,700	2,651,900
Accounts payable	69,100	78,300
Other accrued liabilities	22,400	13,900
Liabilities, Current	459,800	419,400
Regulatory liabilities	185,900	184,000
Operating Lease, Liability, Noncurrent	8,000	8,700
Deferred investment tax credits and other liabilities	1,400	1,400
Deferred Credits and Other Liabilities	529,300	505,700
Liabilities and Equity	3,737,800	3,577,000
Common stock, par value $0.4867 per share (authorized 50,000,000 shares)	11,400	11,100
Additional paid-in capital	896,400	830,500
Retained earnings	594,100	550,300
Accumulated other comprehensive loss	(2,800)	(1,700)
Deferred compensation obligation	12,500	9,800
Treasury Stock, Value	12,500	9,800
Long-term Debt and Capital Lease Obligations, Net of Current Maturities	1,249,600	1,261,700
Less: current maturities	25,500	25,500
Short-term borrowing	245,300	196,500
Customer deposits and refunds	48,100	45,700
Accrued interest	4,900	4,800
Dividends payable	16,000	14,700
Accrued compensation	12,200	23,900
Regulatory liabilities	16,100	16,100
Energy Marketing Contract Liabilities, Current	200	0
Deferred income taxes	315,700	296,100
Environmental liabilities	2,800	2,200
Other pension and benefit costs	14,300	13,200
Energy Marketing Contracts Assets, Noncurrent	100	100
Energy Marketing Contract Liabilities, Noncurrent	1,200	$ 100
Accrued compensation	$ (12,100)