Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 3,703	$ 7,281
Other comprehensive income (loss):
Foreign currency translation adjustment	4,632	12,579
Derivative financial instruments adjustment	374	262
Amortization of prior service costs and net gains or losses	1,950	2,482
Other comprehensive income (loss)	6,956	15,323
Comprehensive income (loss)	$ 10,659	$ 22,604