Derivative and Other Fair Value Instruments (Details 3) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Derivatives designated as hedging instruments:
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net		$ (1,237)	$ (21,693)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(13,647)	(12,606)
Ineffective Portion - Amount of Gain/ (Loss) Reclassifed from Accumulated OCI into Income	$ (3,003)	(3,033)	91
Amount of Gain/(Loss) Recognized in Income on Derivative		8,162	(2,485)
Amount of Gain/(Loss) Recognized in Income on Hedged Item		(8,162)	2,485
Interest Rate Swaps
Derivatives designated as hedging instruments:
Amount of Gain/(Loss) Recognized in Income on Derivative		$ 8,162	$ (2,485)
Hedged Item		Fixed rate debt	Fixed rate debt
Amount of Gain/(Loss) Recognized in Income on Hedged Item		$ (8,162)	$ 2,485
Forward Starting Swaps
Derivatives designated as hedging instruments:
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net		(1,237)	(21,693)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net		(13,647)	(12,606)
Ineffective Portion - Amount of Gain/ (Loss) Reclassifed from Accumulated OCI into Income		$ (3,033)	$ 91