Shareholders' Equity Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Before-tax amount [Abstract]
Foreign currency translation adjustment	$ 14,169	$ 9,128	$ 49,755	$ 12,856
Disposal Group, Including Discontinued Operation, Foreign Currency Translation Gains (Losses)	1,089	0	1,089	(1,407)
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	57	602	(480)	(6,039)
Net hedging loss reclassified into net income	148	279	785	845
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, before Tax	447	(1,725)	1,271	(2,520)
Total other comprehensive income (loss), before tax	15,910	8,284	52,420	3,735
Tax (provision) benefit [Abstract]
Foreign currency translation adjustment	(328)	56	(451)	(539)
Disposal Group, including discontinued operations, Foreign Currency Translation Gains (Losses), tax (provision) benefit	0	0	0	0
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	(22)	(231)	185	2,330
Net hedging loss reclassified into net income	(57)	(108)	(303)	(326)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	(37)	527	(267)	713
Total other comprehensive income (loss) tax benefit	(444)	244	(836)	2,178
Net-of-tax amount [Abstract]
Foreign currency translation adjustment	13,841	9,184	49,304	12,317
Disposal Group, Including Discontinued Operation, Foreign Currency Translation Gains (Losses)	1,089	0	1,089	(1,407)
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	35	371	(295)	(3,709)
Net hedging loss (gain) reclassified into net income	91	171	482	519
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	410	(1,198)	1,004	(1,807)
Total other comprehensive income (loss), net of tax	$ 15,466	$ 8,528	$ 51,584	$ 5,913