Equity and Capital - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income Loss [Roll Forward]
Current period other comprehensive income, net			$ 4,194	$ 22,815
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			(3,768)	(25,015)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,327)	(58,650)
Current period other comprehensive income, net			4,154	22,865
Ending balance	$ (14,173)	$ (35,785)	(14,173)	(35,785)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			7,922	47,880
Accumulated Net Investment Gain (Loss) Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			0	0
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			0	0
Current period other comprehensive income, net			0	0
Ending balance	0	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0	0
AOCI Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(143)	(322)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(301)	(785)
Current period other comprehensive income, net			(11)	(139)
Ending balance	(312)	(924)	(312)	(924)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			132	183
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(3,860)	(25,248)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,647)	(59,478)
Current period other comprehensive income, net			4,194	22,815
Ending balance	(14,453)	(36,663)	(14,453)	(36,663)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,329	43,111	8,054	48,063
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			51	89
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(19)	(43)
Current period other comprehensive income, net			51	89
Ending balance	32	46	32	46
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			0	0
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(3,717)	(24,926)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,346)	(58,693)
Current period other comprehensive income, net			4,205	22,954
Ending balance	(14,141)	(35,739)	(14,141)	(35,739)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			7,922	47,880
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(143)	(322)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(301)	(785)
Current period other comprehensive income, net			(11)	(139)
Ending balance	(312)	(924)	(312)	(924)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			132	183
Partnership Interest [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,346)
Current period other comprehensive income, net	2,298	$ 44,458	4,194	$ 22,815
Ending balance	$ (14,141)		$ (14,141)