Income Taxes Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Effective tax rate reconciliation
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ 60,221	$ 63,049
Income tax calculated at federal statutory rate	$ 12,646	$ 13,240
Income tax calculated at federal statutory rate	21.00%	21.00%
State income tax, net of federal provisions	$ 400	$ 55
State income tax, net of federal provisions	0.70%	0.10%
Flow-through repairs deductions	$ (6,801)	$ (7,853)
Flow-through repairs deductions	(11.30%)	(12.50%)
Production tax credits	(6.40%)	(6.80%)
Production tax credits	$ 3,824	$ 4,307
Plant and depreciation of flow-through items	$ (255)	$ (340)
Plant and depreciation of flow-through items	(0.40%)	(0.50%)
Amortization of excess deferred income tax	$ (411)	$ (265)
Amortization of excess deferred income tax	(0.70%)	(0.40%)
Share-based compensation	$ (253)	$ (261)
Share-based compensation	(0.40%)	(0.40%)
Other, net	$ (391)	$ (291)
Other, net	(0.70%)	(0.50%)
Total Other Reconciling Items	$ (11,535)	$ (13,262)
Total Other Reconciling Items	(19.20%)	(21.00%)
Income tax expense (benefit)	$ 1,111	$ (22)
Income tax expense (benefit)	1.80%	0.00%