CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 14,366	$ 4,876	$ 96,457	$ 70,753
Other Comprehensive Income:
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes of $82, $59, $166 and $113 respectively	304	220	927	645
Total other comprehensive income	304	220	927	645
Comprehensive income	$ 14,670	$ 5,096	$ 97,384	$ 71,398