Condensed Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Condensed Consolidated Statements of Comprehensive Income (unaudited) [Abstract]
Net income	$ 6,835	$ 1,958	$ 42,654	$ 28,532
Other comprehensive income (loss):
Change in unrecognized pension and post-retirement benefit costs	0	0	0	28
Income tax (provision) benefit on change in unrecognized pension and post-retirement benefit costs	111	(30)	0	(21)
Foreign currency translation adjustments	69	(7,003)	(219)	(10,721)
Income tax (provision) benefit on foreign currency translation adjustments	(57)	868	(783)	808
Other comprehensive income (loss)	123	(6,165)	(1,002)	(9,906)
Comprehensive income (loss)	6,958	(4,207)	41,652	18,626
Comprehensive loss attributable to non-controlling interest	(130)	(607)	(55)	(1,285)
Comprehensive income (loss) attributable to controlling interest	$ 7,088	$ (3,600)	$ 41,707	$ 19,911