Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Share Capital	Additional Paid in Capital	Deficit	Deficit Cumulative Effect, Period of Adoption, Adjustment
Balance, beginning of year at Dec. 31, 2018		$ 10,290	$ 1,318,048	$ (298,588)	$ (389)
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (Note 9)			0
Stock-based compensation (Note 9)			2,120
Repurchase of Common Stock		(20)	(37,541)
Net income (loss)	$ 38,690			38,690
Balance, end of year at Dec. 31, 2019	1,032,610	10,270	1,282,627	(260,287)	0
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (Note 9)			0
Stock-based compensation (Note 9)			2,391
Repurchase of Common Stock		0	0
Net income (loss)	(777,967)			(777,967)
Balance, end of year at Dec. 31, 2020	257,034	10,270	1,285,018	(1,038,254)	$ 0
Increase (Decrease) in Stockholders' Equity
Exercise of stock options (Note 9)			100
Stock-based compensation (Note 9)			2,464
Repurchase of Common Stock		0	0
Net income (loss)	42,482			42,482
Balance, end of year at Dec. 31, 2021	$ 302,080	$ 10,270	$ 1,287,582	$ (995,772)