CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Comprehensive Income (Loss)
Net Income	$ 59,110	$ 63,071
Other comprehensive income, net of tax:
Foreign currency translation adjustment	(2)	(76)
Postretirement medical liability adjustment	(158)	(158)
Total Other Comprehensive (Loss) Income	(47)	(121)
Comprehensive Income	59,063	62,950
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	$ 113	$ 113