Equity and Capital - Accumulated Other Comprehensive Income (Loss) (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 Loss [Roll Forward]
Amortization of loss on derivative instruments	$ (2,366)	$ (2,366)	$ (4,732)	$ (4,729)
Loss on Settlement of Derivative Instruments [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance at December 31, 2012			(61,991)
Net gain on cash flow derivative instruments			0
Amortization of loss on derivative instruments			(4,724)
Current period other comprehensive income, net			4,724
Ending balance at June 30, 2013	(57,267)		(57,267)
Fair Value of Derivative Instruments [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance at December 31, 2012			4,276
Net gain on cash flow derivative instruments			21,664
Amortization of loss on derivative instruments			(8)
Current period other comprehensive income, net			21,672
Ending balance at June 30, 2013	25,948		25,948
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance at December 31, 2012			(57,715)
Net gain on cash flow derivative instruments			21,664
Amortization of loss on derivative instruments			(4,732)
Current period other comprehensive income, net			26,396
Ending balance at June 30, 2013	$ (31,319)		$ (31,319)