Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 9,031	$ (22,321)
Other comprehensive income (loss):
Foreign currency translation adjustment	(2,648)	(11,529)
Derivative financial instruments adjustment	(236)	(3,775)
Amortization of prior service costs and net gains or losses	3,319	2,931
Other comprehensive income (loss)	435	(12,373)
Comprehensive income (loss)	9,466	(34,694)
Amortization of prior service costs and net gains or losses, tax	924	836
Other Comprehensive Income, Other, Net of Tax	435	(12,373)
Foreign currency translation adjustment, tax (benefit)	(272)	(1,283)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	9,466	(34,694)
Other Comprehensive Income, Other, Net of Tax	435	(12,373)
Net Income (Loss) Attributable to Parent	$ 9,031	$ (22,321)