Components of Accumulated Other Comprehensive Income (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 Income Loss [Line Items]
Balance, beginning of period		$ 2,233,169	$ 1,843,551	$ 2,263,153	$ 1,526,133
Reclassifications from AOCI to earnings:
Balance, end of period		2,239,097	2,405,419	2,239,097	2,405,419
Pension and Other Postretirement Employee Benefits
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		(28,969)	(42,974)	(28,494)	(51,369)
Unrecognized gains (losses) arising in AOCI during the period:
Gross		0	0	0	(6,157)
Tax effect		0	0	0	1,570
Reclassifications from AOCI to earnings:
Pension settlement	[1]	0	0	0	14,165
Other	[1]	(177)	1,228	(529)	4,488
Tax effect		45	(314)	133	(4,757)
Net of tax amount		(132)	914	(396)	9,309
Other reclassifications		0	0	(211)	0
Balance, end of period		(29,101)	(42,060)	(29,101)	(42,060)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		126,530	93,936	126,146	8,131
Unrecognized gains (losses) arising in AOCI during the period:
Gross		34,334	28,802	43,207	116,229
Tax effect		(727)	4,098	(899)	(821)
Reclassifications from AOCI to earnings:
Gross	[2]	(5,266)	(170)	(13,829)	3,274
Tax effect		123	(5)	324	(152)
Net of tax amount		28,464	32,725	28,803	118,530
Other reclassifications		0	0	45	0
Balance, end of period		154,994	126,661	154,994	126,661
Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Balance, beginning of period		97,561	50,962	97,652	(43,238)
Reclassifications from AOCI to earnings:
Balance, end of period		$ 125,893	$ 84,601	$ 125,893	$ 84,601

[1] Included in the computation of net periodic pension costs.

[2] Included in Interest expense, net on the Condensed Consolidated Statement of Operations.