Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	$ 1,428,189	$ 2,019,614	$ 2,130,825	$ 1,970,434
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI, net of tax	25	816	75	2,476
Net current-period other comprehensive income (loss)	25	816	75	2,476
Equity, ending balance	1,416,675	2,059,211	1,416,675	2,059,211
Tax on amount reclassified from AOCI		253
Defined Benefit Pension Items
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	(77,277)	(72,059)	(77,327)	(73,713)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI, net of tax	25	813	75	2,467
Net current-period other comprehensive income (loss)	25	813	75	2,467
Equity, ending balance	(77,252)	(71,246)	(77,252)	(71,246)
Tax on amount reclassified from AOCI	8		24	768
Other
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	(144)	(190)	(144)	(196)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI, net of tax	0	3	0	9
Net current-period other comprehensive income (loss)	0	3	0	9
Equity, ending balance	(144)	(187)	(144)	(187)
AOCI Attributable to Parent
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	(77,421)	(72,249)	(77,471)	(73,909)
Equity, ending balance	$ (77,396)	$ (71,433)	$ (77,396)	$ (71,433)