Derivative Instruments, Hedging Activities and Fair Value (Details 3) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Foreign Currency Derivatives
Proceeds from cross-currency interest rate swap termination			$ 16,625	$ 0
Pre-tax net gains (losses) on certain loans designated as hedges of net investments in foreign subsidiaries	$ 16,400	$ 1,500	20,300		$ 4,600
Foreign currency forward exchange contracts
Foreign Currency Derivatives
U.S. Dollar Equivalent	536,479		536,479		592,414
Recognized Gain (Loss)			4,935	4,090
Foreign currency forward exchange contracts | British pounds sterling | Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	41,995		41,995		43,511
Recognized Gain (Loss)			3,309	822
Foreign currency forward exchange contracts | British pounds sterling | Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	1,061		1,061		2,062
Recognized Gain (Loss)			(33)	(54)
Foreign currency forward exchange contracts | Euros | Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	310,051		310,051		336,397
Recognized Gain (Loss)			(1,675)	547
Foreign currency forward exchange contracts | Euros | Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	138,899		138,899		167,037
Recognized Gain (Loss)			3,511	2,497
Foreign currency forward exchange contracts | Other currencies | Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	35,952		35,952		35,426
Recognized Gain (Loss)			(198)	316
Foreign currency forward exchange contracts | Other currencies | Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	$ 8,521		8,521		$ 7,981
Recognized Gain (Loss)			$ 21	$ (38)