Derivative Instruments (Details 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative [Line Items]
Loss (gain) on derivatives, net	$ 351,000	$ (2,716,000)	$ 351,000	$ (407,000)
Interest expense	121,065,000	109,465,000	241,898,000	218,303,000
Interest Rate Swap [Member]
Derivative [Line Items]
Gain (loss) recognized in OCI	(4,000)	(4,000)	(7,000)	(8,000)
Interest expense	(436,000)	(476,000)	(879,000)	(951,000)
Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain (loss) recognized in OCI	$ (67,899,000)	$ 14,680,000	$ (49,410,000)	$ 90,537,000