Derivative Instruments - Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) (Details) (Interest Rate Contract [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) in Other Comprehensive Income	$ 0	$ (30)	$ (136)
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Interest Expenese (Effective Portion)	0	0	0
Derivative Instruments, Losses Reclassified into Earnings as a Result of Discontinuance of Cash Flow Hedge Accounting	0	166	0
Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) in Other Comprehensive Income	0	21,297	(21,290)
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Interest Expenese (Effective Portion)	0	0	0
Derivative Instruments, Losses Reclassified into Earnings as a Result of Discontinuance of Cash Flow Hedge Accounting	0	5,807	0
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) in Other Comprehensive Income	0	0	(5,814)
Derivative Instruments, Gain (Loss) Reclassified from AOCI into Interest Expenese (Effective Portion)	0	0	0
Derivative Instruments, Losses Reclassified into Earnings as a Result of Discontinuance of Cash Flow Hedge Accounting	$ 0	$ 0	$ 0