Components of Accumulated Other Comprehensive Loss Dilution of Equity Method Investment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense	$ 11,234	$ 12,000	$ 17,487	$ 9,834
Amount Reclassified from Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total before tax				4,813
Income tax expense				(1,776)
Total amounts reclassified from accumulated other comprehensive loss in connection with loss on dilution of equity method investment				3,037
Amount Reclassified from Accumulated Other Comprehensive Loss | Foreign exchange translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total before tax				4,880
Amount Reclassified from Accumulated Other Comprehensive Loss | Cash flow hedging instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total before tax				168
Amount Reclassified from Accumulated Other Comprehensive Loss | Defined benefit pension obligations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total before tax				$ (235)