Derivative Instruments, Hedging Activities and Fair Value (Details 3) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Foreign Currency Derivatives
Pre-tax net gains (losses) on certain loans designated as hedges of net investments in foreign subsidiaries	$ 3,100,000	$ 200,000
Foreign currency forward exchange contracts
Foreign Currency Derivatives
U.S. Dollar Equivalent	486,867,000		468,822,000
Recognized Gain (Loss)	3,047,000		(133,000)
Foreign currency forward exchange contracts | British pounds sterling | Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	163,000		37,943,000
Recognized Gain (Loss)	4,000		179,000
Foreign currency forward exchange contracts | British pounds sterling | Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	2,138,000		2,783,000
Recognized Gain (Loss)	(46,000)		(4,000)
Foreign currency forward exchange contracts | Euros | Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	230,113,000		193,370,000
Recognized Gain (Loss)	1,473,000		2,993,000
Foreign currency forward exchange contracts | Euros | Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	210,841,000		194,084,000
Recognized Gain (Loss)	810,000		(3,767,000)
Foreign currency forward exchange contracts | Other currencies | Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	35,657,000		12,641,000
Recognized Gain (Loss)	840,000		439,000
Foreign currency forward exchange contracts | Other currencies | Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	7,955,000		28,001,000
Recognized Gain (Loss)	$ (34,000)		$ 27,000