CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, deferred income taxes	$ 393	$ (3,577)
Net gain (loss) on cash flow hedging instruments, deferred income taxes	256	14
Pension liability adjustments, deferred income taxes	(522)	(685)
Unrealized gain (loss) on marketable securities, deferred income taxes	$ (3)	$ 4