Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Accumulated Other Comprehensive Income [Roll Forward]
Foreign Currency Translation Adjustment, Beginning Balance			$ 47,845
Foreign Currency Translation Adjustment, Other comprehensive (loss)/income before reclassifications			(53,171)
Foreign Currency Translation Adjustment, Amounts reclassified from accumulated other comprehensive income			0
Foreign Currency Translation Adjustment, Current period change	(47,824)	(5,801)	(53,171)	445
Foreign Currency Translation Adjustment, Ending Balance	(5,326)		(5,326)
Defined Benefit Plans, Beginning Balance			(148)
Defined Benefit Plans, Other comprehensive income before reclassifications			196
Defined Benefit Plans, Amounts reclassified from accumulated other comprehensive income			0
Defined Benefit Plans, Current Period Change	98	32	196	(377)
Defined Benefit Plans, Ending Balance	48		48
Net Unrealized Losses on Cash Flow Hedges, Beginning Balance			(426)
Net unrealized gain on qualifying cash flow hedges, net of tax	12,274	617	16,712	1,063
Net Unrealized Losses on Cash Flow Hedges, Ending Balance	16,286		16,286
Accumulated Other Comprehensive Income, Beginning Balance			47,271
Accumulated Other Comprehensive Income, Current Period Change			(36,263)
Accumulated Other Comprehensive Income, Ending Balance	11,008		11,008
Interest Rate Swap [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax			759
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Net Unrealized Gain/(Loss) on Cash Flow Hedges, Other comprehensive income before reclassifications			17,851
Net loss on cash flow hedge reclassified from accumulated other comprehensive income			(1,139)
Net unrealized gain on qualifying cash flow hedges, net of tax	12,274	617	16,712	1,063
OCI before reclassifications [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated Other Comprehensive Income, Current Period Change			(35,124)
Reclassified from accumulated OCI [Member]
Accumulated Other Comprehensive Income [Roll Forward]
Accumulated Other Comprehensive Income, Current Period Change			$ (1,139)