Shareholders' Equity Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Before-tax amount [Abstract]
Foreign currency translation adjustment	$ (2,254)	$ 16,293
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	171	1,436
Net hedging (gain) loss reclassified into net income	(264)	(19)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment and Tax	342	0
Net defined benefit plan loss reclassified to net income	179	420
Total other comprehensive income (loss), before tax	(1,826)	18,130
Tax (provision) benefit [Abstract]
Foreign currency translation adjustment	(132)	7
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	40	(253)
Net hedging (gain) loss reclassified into net income	188	5
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, Tax	(15)	0
Net defined benefit plan loss reclassified to net income	(35)	(6)
Total other comprehensive income (loss) tax benefit	(46)	247
Net-of-tax amount [Abstract]
Foreign currency translation adjustment	(2,386)	16,300
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	211	1,183
Net hedging (gain) loss reclassified into net income	(76)	(14)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	(327)	0
Net defined benefit plan loss reclassified to net income	144	414
Total other comprehensive income (loss), net of tax	$ (1,780)	$ 17,883