Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Net income (loss)	$ 528,584	$ (298,665)	$ (174,683)
Other comprehensive income (loss):
Unrealized gains (losses) on investments	(957)	(50)	149
Amortization of actuarial loss	55	23	0
Adjustment to projected benefit obligations, net of tax	1,081	(650)	(736)
Other comprehensive income (loss)	179	(677)	(587)
Comprehensive income (loss)	$ 528,763	$ (299,342)	$ (175,270)