Equity and Capital - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accumulated Other Comprehensive Income Loss [Line Items]
Document Fiscal Year Focus			2015
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 2,250	$ 2,318	$ 4,500	$ 4,837
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			4,464	(24,039)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(58,498)	(17,883)
Current period other comprehensive income, net			8,964	(19,202)
Ending balance	(49,534)	(37,085)	(49,534)	(37,085)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			4,500	4,837
Partnership Interest [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(57,748)
Current period other comprehensive income, net	20,596	(7,921)	8,964	(19,202)
Ending balance	(48,799)		(48,799)
Partnership Interest [Member] | General Partner [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Current period other comprehensive income, net			0	0
Partnership Interest [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Current period other comprehensive income, net			8,949	(19,008)
Controlling [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			4,558	(24,669)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(57,748)	(17,404)
Current period other comprehensive income, net			8,979	(19,920)
Ending balance	(48,769)	(37,324)	(48,769)	(37,324)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			4,421	4,749
Controlling [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(30)	912
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			0	0
Current period other comprehensive income, net			(30)	912
Ending balance	(30)	912	(30)	912
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0	0
Controlling [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			4,528	(23,757)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(57,748)	(17,404)
Current period other comprehensive income, net			8,949	(19,008)
Ending balance	(48,799)	(36,412)	(48,799)	(36,412)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			4,421	4,749
Noncontrolling Interest [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(64)	(284)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(750)	(479)
Current period other comprehensive income, net			15	(196)
Ending balance	(735)	(675)	(735)	(675)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			79	88
Noncontrolling Interest [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			0	2
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			0	0
Current period other comprehensive income, net			0	2
Ending balance	0	2	0	2
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0	0
Noncontrolling Interest [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(64)	(282)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(750)	(479)
Current period other comprehensive income, net			15	(194)
Ending balance	$ (735)	$ (673)	(735)	(673)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			$ 79	$ 88