Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 48,259	$ 24,842	$ 38,251
Foreign currency translation adjustment:
Unrealized foreign currency translation adjustment (net of tax benefit of $623 in 2019, tax of $281 in 2018 and tax benefit of $371 in 2017)	(3,723)	(10,762)	7,792
Derivative financial instruments adjustment	294	(2,060)	(404)
Pension & other postretirement benefit adjustments:
Net gains (losses) and prior service costs (net of tax benefit of $6,417 in 2019, tax benefit of $319 in 2018 and tax benefit of $2,518 in 2017)	(22,508)	(1,118)	(8,634)
Amortization of prior service costs and net gains or losses (net of tax of $2,359 in 2019, tax of $3,028 in 2018 and tax of $4,234 in 2017)	8,273	10,622	7,811
Other comprehensive income (loss)	(17,664)	(3,318)	6,565
Comprehensive income (loss)	$ 30,595	$ 21,524	$ 44,816