Equity and Capital - Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income Loss [Roll Forward]
Net gain (loss) on cash flow derivative instruments	$ (13,669)	$ 3,366
Amounts reclassified from other comprehensive income	2,474	2,366
Loss on Settlement of Derivative Instruments [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(52,542)	(61,991)
Net gain (loss) on cash flow derivative instruments	0	0
Amounts reclassified from other comprehensive income	2,362	2,362
Current period other comprehensive income, net	2,362	2,362
Ending balance	(50,180)	(59,629)
Fair Value of Derivative Instruments [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	35,138	4,276
Net gain (loss) on cash flow derivative instruments	(13,669)	3,366
Amounts reclassified from other comprehensive income	112	4
Current period other comprehensive income, net	(13,557)	3,370
Ending balance	21,581	7,646
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(17,404)	(57,715)
Current period other comprehensive income, net	(11,195)	5,732
Ending balance	$ (28,599)	$ (51,983)