CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (in thousands) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (764,614)	$ (187,001)	$ 508,407
Other comprehensive income (loss), net of tax:
Pension liability adjustment	[1]	(2,279)	1,061	4,378
Total other comprehensive income (loss), net of tax		(2,279)	1,061	4,378
Total comprehensive income (loss)		$ (766,893)	$ (185,940)	$ 512,785

[1] (1)    Please refer to Note 8 – Pension Benefits for additional discussion of the pension liability adjustment.