Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	$ 2,099,808	$ 1,984,029	$ 2,130,825	$ 1,970,434
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI, net of tax	25	830	50	1,660
Net current-period other comprehensive income (loss)	25	830	50	1,660
Equity, ending balance	1,428,189	2,019,614	1,428,189	2,019,614
Tax on amount reclassified from AOCI		258
Defined Benefit Pension Items
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	(77,302)	(72,886)	(77,327)	(73,713)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI, net of tax	25	827	50	1,654
Net current-period other comprehensive income (loss)	25	827	50	1,654
Equity, ending balance	(77,277)	(72,059)	(77,277)	(72,059)
Tax on amount reclassified from AOCI	8		16	515
Other
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	(144)	(193)	(144)	(196)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassified from AOCI, net of tax	0	3	0	6
Net current-period other comprehensive income (loss)	0	3	0	6
Equity, ending balance	(144)	(190)	(144)	(190)
AOCI Attributable to Parent
Accumulated Other Comprehensive Loss [Roll Forward]
Equity, beginning balance	(77,446)	(73,079)	(77,471)	(73,909)
Equity, ending balance	$ (77,421)	$ (72,249)	$ (77,421)	$ (72,249)