Unaudited Condensed Consolidated Statements of Comprehensive Income - 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)	$ 8,398	$ (441)	$ 20,164	$ 5,476
Foreign currency translation adjustment	(18)	(517)	1,725	(1,335)
Deferred gain on available for sale securities	78	134	542	298
Current period cash flow hedging activity, net of $1,310 and $941 tax expense in the three and nine months ended September 30, 2017, and $169 tax expense and $819 tax benefit in the three and nine months ended September 30, 2016, respectively.	2,402	340	1,543	(1,541)
Reclassification of hedging activities into earnings, net of $1,344 and $1,255 tax expense in the three and nine months ended September 30, 2017, respectively, and $149 and $254 tax benefit in the three and nine months ended September 30, 2016, respectively.	(2,509)	312	(2,369)	420
Reclassification of pension and postretirement adjustments into earnings, net of $38 and $228 tax benefit in the three and nine months ended September 30, 2017, and $88 and $271 tax benefit in the three and nine months ended September 30, 2016, respectively.	191	166	515	468
Total other comprehensive income (loss)	144	435	1,956	(1,690)
Comprehensive income (loss)	$ 8,542	$ (6)	$ 22,120	$ 3,786