CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Income	$ 186,840	$ 155,215	$ 202,120
Other comprehensive income (loss), net of tax:
Postretirement medical liability adjustment	(436)	1,840	(131)
Foreign currency translation adjustment	(57)	87	(35)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(452)	(452)	(452)
Total Other Comprehensive Income (Loss)	(41)	2,379	286
Comprehensive Income	$ 186,799	$ 157,594	$ 202,406