Equity and Capital - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Accumulated Other Comprehensive Income Loss [Roll Forward]
Current period other comprehensive income, net			$ 1,896	$ (21,642)
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			(3,770)	(26,256)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,327)	(58,650)
Current period other comprehensive income, net			1,868	(21,382)
Ending balance	$ (16,459)	$ (80,032)	(16,459)	(80,032)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			5,638	4,874
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			(103)	(375)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(301)	(785)
Current period other comprehensive income, net			(15)	(297)
Ending balance	(316)	(1,082)	(316)	(1,082)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			88	78
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			(3,830)	(26,594)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,647)	(59,478)
Current period other comprehensive income, net			1,896	(21,642)
Ending balance	(16,751)	(81,120)	(16,751)	(81,120)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	3,071	2,500	5,726	4,952
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax			43	37
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(19)	(43)
Current period other comprehensive income, net			43	37
Ending balance	24	(6)	24	(6)
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			(3,727)	(26,219)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,346)	(58,693)
Current period other comprehensive income, net			1,911	(21,345)
Ending balance	(16,435)	(80,038)	(16,435)	(80,038)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			5,638	4,874
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			(103)	(375)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(301)	(785)
Current period other comprehensive income, net			(15)	(297)
Ending balance	(316)	(1,082)	(316)	(1,082)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax			88	78
Partnership Interest [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance			(18,346)
Current period other comprehensive income, net	(723)	$ (7,273)	1,896	$ (21,642)
Ending balance	$ (16,435)		$ (16,435)