Accumulated Other Comprehensive Loss - Reclassification Out of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Interest expense	$ (114,308)	$ (80,698)	$ (70,709)
Income taxes	59,473	49,761	43,544
Other income	(41,672)	(11,228)	(25,724)
Net income	414,707	367,489	$ 378,131
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Net income	(366)	(2,346)
Reclassification adjustment for loss on derivative instruments included in net income | Reclassification out of Accumulated Other Comprehensive Income | Interest Rate Contract
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Interest expense	(96)	(590)
Income taxes	15	177
Net income	(81)	(413)
Amortization of postretirement liability losses included in net periodic benefit credit | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Income taxes	78	597
Other income	(320)	(2,416)
Net income	(242)	(1,819)
Reclassification adjustment on available-for-sale investments included in net income | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Loss [Line Items]
Income taxes	11	31
Other income	(54)	(145)
Net income	$ (43)	$ (114)