Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net Income (Loss)	$ 31,054	$ (37,060)	$ 35,929	$ 18,803
Other comprehensive income (loss), net of tax
Cash flow hedge adjustments, net of taxes of $0 and $(0) for the three and six months ended June 30, 2018	(1,801)	1,119	14	1,119
Foreign currency translation adjustment, net of taxes of $0 and $8 for the three months ended June 30, 2018 and 2017, respectively, and $0 and $56 for the six months ended June 30, 2018 and 2017, respectively	(17,687)	8,888	(2,290)	10,914
Other Adjustments, Net of Taxes of $0 for all periods	4	(151)		(148)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent			5
Other comprehensive income (loss), net of taxes	(19,484)	9,856	(2,271)	11,885
Comprehensive Income (Loss)	11,570	(27,204)	33,658	30,688
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	569	(685)	(4)	(685)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	0	(8)	0	(56)
Other Comprehensive (Income) Loss, Other Adjustments, Tax	$ 0	$ 0	$ 0	$ 0