Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Consolidated Statements of Comprehensive Income (Loss)
Net income (loss)	$ 1,330,914	$ 337,573	$ (344,615)
Derivative instruments
Comprehensive income (loss) before tax	1,763	2,128	(1,328)
Other comprehensive income, derivative instruments, net of tax	1,763	2,128	(1,328)
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	57,930	47,562	(39,732)
(Benefit from) provision for income taxes	(12,548)
Other comprehensive income (loss), pension, postretirement and other post-employment benefits, net of tax	45,382	47,562	(39,732)
Available-for-sale securities
Comprehensive income (loss) before tax	161	169	(330)
(Benefit from) provision for income taxes	(35)
Other comprehensive income, available-for-sale securities, net of tax	126	169	(330)
Total other comprehensive income (loss)	47,271	49,859	(41,390)
Total comprehensive income (loss)	$ 1,378,185	$ 387,432	$ (386,005)