Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 134,287	$ 112,832
Other comprehensive income, before tax:
Foreign currency translation adjustments	142	496
Recognition of previously deferred post-retirement benefit plan costs	975	1,225
Realized gain on available-for-sale investment during the period	(20,800)	0
Other comprehensive (loss) income, before tax	(19,683)	1,721
Income tax effect related to components of other comprehensive income	5,065	(443)
Other comprehensive income, net of tax	(14,618)	1,278
Comprehensive income	119,669	114,110
Comprehensive income attributable to redeemable noncontrolling interest	(53)	(215)
Total comprehensive income	$ 119,616	$ 113,895