CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (94,715)	$ 51,625	$ 68,379	$ 12,928
Other comprehensive loss:
Change in pension and postretirement obligations, net of tax of $0 and $0 in 2016	(1)	(1)	(2)	(2)
Total Other Comprehensive Income (Loss), Net of Tax	(1)	(1)	(2)	(2)
Comprehensive income (loss)	$ (94,716)	$ 51,624	$ 68,377	$ 12,926