Income Taxes Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Effective tax rate reconciliation
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ 27,119	$ 37,707	$ 118,561	$ 139,358
Income tax calculated at federal statutory rate	$ 5,697	$ 7,918	$ 24,897	$ 29,265
Income tax calculated at federal statutory rate	21.00%	21.00%	21.00%	21.00%
State income tax, net of federal provisions	$ 145	$ 397	$ 976	$ 674
State income tax, net of federal provisions	0.50%	1.10%	0.80%	0.50%
Flow-through repairs deductions	$ (3,374)	$ (3,473)	$ (13,488)	$ (15,553)
Flow-through repairs deductions	(12.40%)	(9.20%)	(11.40%)	(11.20%)
Production tax credits	$ 1,668	$ 1,877	$ 8,050	$ 8,446
Production tax credits	(6.20%)	(5.00%)	(6.80%)	(6.10%)
Income tax return to accrual adjustment	(3.40%)	1.00%	(0.80%)	0.30%
Income tax return to accrual adjustment	$ (926)	$ 389	$ (926)	$ 389
Amortization of excess deferred income tax	$ (246)	$ (126)	$ (819)	$ (534)
Amortization of excess deferred income tax	(0.90%)	(0.30%)	(0.70%)	(0.40%)
Share-based compensation	$ 0	$ (62)	$ (253)	$ (323)
Share-based compensation	0.00%	(0.20%)	(0.20%)	(0.20%)
Plant and depreciation of flow-through items	$ 266	$ (288)	$ 409	$ (812)
Plant and depreciation of flow-through items	1.00%	(0.80%)	0.30%	(0.60%)
Other, net	$ (143)	$ (367)	$ (449)	$ (806)
Other, net	(0.50%)	(1.00%)	(0.30%)	(0.50%)
Total Other Reconciling Items	$ (5,946)	$ (5,407)	$ (22,600)	$ (25,411)
Total Other Reconciling Items	(21.90%)	(14.40%)	(19.10%)	(18.20%)
Income tax expense	$ (249)	$ 2,511	$ 2,297	$ 3,854
Income tax expense	(0.90%)	6.60%	1.90%	2.80%