Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income (loss)	$ (6,042)	$ (25,299)
Derivative instruments
Comprehensive income (loss) before tax	689	(2,669)
Other comprehensive income (loss), derivative instruments, net of tax	689	(2,669)
Pension, postretirement and other post-employment benefits
Comprehensive income (loss) before tax	547	(14,267)
Other comprehensive income (loss), pension, postretirement and other post-employment benefits, net of tax	547	(14,267)
Available-for-sale securities
Comprehensive income (loss) before tax	101	(467)
Other comprehensive income (loss), available-for-sale securities, net of tax	101	(467)
Total other comprehensive income (loss)	1,337	(17,403)
Total comprehensive income (loss)	$ (4,705)	$ (42,702)