Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,199	$ (1,383)	$ 2,674	$ (2,484)
Other comprehensive income (loss):
Foreign currency translation adjustments	266	(368)	9,199	531
Retirement plans related adjustments	1,058	3,031	807	4,333
Unrealized (loss) gain on cash flow hedges	(442)	78	(510)	210
Other comprehensive income (loss) before tax	882	2,741	9,496	5,074
Income tax (benefit) expense	(178)	322	(197)	427
Other comprehensive income (loss), net of tax	1,060	2,419	9,693	4,647
Total comprehensive income (loss)	$ 3,259	$ 1,036	$ 12,367	$ 2,163