Shareholders' Equity Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Before-tax amount [Abstract]
Foreign currency translation adjustment	$ 15,066	$ 10,458
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	97	(4,513)
Net hedging loss reclassified into net income	378	286
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax	0	(113)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax	406	(342)
Total other comprehensive income (loss), before tax	15,947	5,776
Tax (provision) benefit [Abstract]
Foreign currency translation adjustment	(50)	(352)
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	(37)	1,731
Net hedging loss reclassified into net income	(146)	(110)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, before Reclassification Adjustments, Tax	0	34
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax	(5)	103
Total other comprehensive income (loss) tax benefit	(238)	1,406
Net-of-tax amount [Abstract]
Foreign currency translation adjustment	15,016	10,106
Net unrealized gain (loss) on derivative instruments designated as cash flow hedges	60	(2,782)
Net hedging loss (gain) reclassified into net income	232	176
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	0	(79)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	401	(239)
Total other comprehensive income (loss), net of tax	(15,709)	(7,182)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Net-of-tax amount [Abstract]
Total other comprehensive income (loss), net of tax	(15,016)	(10,106)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Net-of-tax amount [Abstract]
Total other comprehensive income (loss), net of tax	$ (292)	$ 2,606