CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 51,625	$ (2,521)	$ 12,928	$ 7,774
Other comprehensive loss:
Change in pension and postretirement obligations, net of tax of $0 and $0 in 2016	(1)	0	(2)	0
Total Other Comprehensive Income (Loss), Net of Tax	(1)	0	(2)	0
Comprehensive income (loss)	$ 51,624	$ (2,521)	$ 12,926	$ 7,774