Equity and Capital - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
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	$ (16,581)	$ (13,739)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(58,650)	(57,748)
Current period other comprehensive income, net	(14,164)	(11,529)
Ending balance	(72,814)	(69,277)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,417	$ 2,210
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
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	0	$ 0
Current period other comprehensive income, net	0	0
Ending balance	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	(204)	(143)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(785)	(750)
Current period other comprehensive income, net	(168)	(104)
Ending balance	(953)	(854)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	36	39
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(16,821)	(13,882)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(59,478)	(58,498)
Current period other comprehensive income, net	(14,368)	(11,633)
Ending balance	(73,846)	(70,131)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,453	$ 2,249
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(36)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(43)	$ 0
Current period other comprehensive income, net	(36)	0
Ending balance	(79)	0
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	(16,617)	(13,739)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(58,693)	(57,748)
Current period other comprehensive income, net	(14,200)	(11,529)
Ending balance	(72,893)	(69,277)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,417	2,210
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	(204)	(143)
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(785)	(750)
Current period other comprehensive income, net	(168)	(104)
Ending balance	(953)	(854)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	36	39
Partnership Interest [Member]
Accumulated Other Comprehensive Income Loss [Roll Forward]
Beginning balance	(58,693)
Current period other comprehensive income, net	(14,368)	(11,633)
Ending balance	(72,893)
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	$ (14,200)	$ (11,529)