Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2021

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of Regulatory Assets And Liabilities

	Note Reference	Remaining Amortization Period	December 31,
			2021		2020
			(in thousands)
Flow-through income taxes	12	Plant Lives	$	464,663	$	420,925
Excess deferred income taxes	12	Plant Lives	60,813		67,256
Pension	14	See Note 14	98,336		138,567
Deferred financing costs		Various	25,636		28,350
Employee related benefits	14	Various	21,648		22,516
Supply costs		18 months	88,329		8,116
State & local taxes & fees		Various	6,520		17,910
Environmental clean-up	18	Various	11,262		11,127
Other		Various	29,020		31,650
Total Regulatory Assets			$	806,227	$	746,417
Removal cost	6	Various	$	479,294	$	464,669
Excess deferred income taxes	12	Plant Lives	158,047		165,279
Supply costs		1 Year	16,430		13,847
Gas storage sales		18 years	7,466		7,887
Rates subject to refund		1 Year	1,971		32,496
State & local taxes & fees		1 Year	3,021		1,783
Environmental clean-up		Various	508		656
Other		Various	202		655
Total Regulatory Liabilities			$	666,939	$	687,272