Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2022

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets And Liabilities

	Note Reference	Remaining Amortization Period	December 31,
			2022		2021
			(in thousands)
Flow-through income taxes	12	Plant Lives	$	509,038	$	464,663
Supply costs		18 months	101,096		88,329
Pension	14	See Note 14	87,965		98,336
Excess deferred income taxes	12	Plant Lives	54,364		60,813
Employee related benefits	14	See Note 14	27,920		21,648
Deferred financing costs		See Note 11	22,620		25,636
State & local taxes & fees		1 Year	15,684		6,520
Environmental clean-up	18	Undetermined	10,963		11,262
Other		Various	22,929		29,020
Total Regulatory Assets			$	852,579	$	806,227
Removal cost	6	Plant Lives	$	502,289	$	479,294
Excess deferred income taxes	12	Plant Lives	148,989		158,047
Supply costs		1 Year	11,536		16,430
Gas storage sales		17 years	7,046		7,466
State & local taxes & fees		1 Year	2,327		3,021
Environmental clean-up		1 Year	592		508
Rates subject to refund		Not applicable	—		1,971
Other		Various	2,579		202
Total Regulatory Liabilities			$	675,358	$	666,939