Derivative Financial Instruments Effect of Net Investment Hedge Nonderivative Financial Instrument on OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 200,607	$ 135,060		$ 193,920	$ 180,616	$ 194,989	$ 80,636	$ 32,245	$ 24,258
Net unrealized gain (loss) on derivative instruments, designated as cash flow hedges	76	(566)	$ 2
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(1,010)	(1,054)	(431)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(200,607)	(135,060)		$ (193,920)	$ (180,616)	$ (194,989)	$ (80,636)	$ (32,245)	$ (24,258)
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	14,380	14,380	14,380							$ 14,380
Accumulated Other Comprehensive Income (Loss), Net of Tax	(14,380)	(14,380)	(14,380)							(14,380)
Accumulated Net Gain (Loss) from Derivative and Nonderivative Instruments Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	14,062	15,148	15,636							16,069
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (14,062)	$ (15,148)	$ (15,636)							$ (16,069)