Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Parent Company [Member]
Cash flows from operating activities:
Consolidated net income	$ (350,745)	$ (156,277)	$ (119,279)
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(1,083)	(27)	(35)
Depreciation and amortization	(294,897)	(301,744)	(189,673)
Stock compensation expense	6,147	4,226	2,268
Redeemable stock issued	924	874	692
Amortization of debt premium	(15,515)	(21,282)	(5,870)
(Gain) loss from investments in real estate joint ventures	6	(3,142)	(338)
Loss on debt extinguishment	2,855	2,586	426
Derivative interest (credit) expense	(2,274)	(3,084)	911
Settlement of forward swaps	(1,908)	(3,625)	9,617
Gain on sale of non-depreciable real estate assets	(172)	(350)	0
Gain on sale of depreciable real estate assets excluded from discontinued operations	(189,958)	(42,649)	0
Gain on sale of discontinued operations	0	(5,394)	(76,844)
Net casualty (gain) loss and other settlement proceeds	(473)	476	50
Changes in assets and liabilities:
Restricted cash	2,091	(8,704)	(11,844)
Other assets	12,475	2,013	59,032
Accounts payable	2,578	3,348	48,674
Accrued expenses and other	6,307	7,543	19,890
Security deposits	(1,235)	(1,244)	(147)
Net cash provided by operating activities	463,721	385,378	258,380
Cash flows from investing activities:
Purchases of real estate and other assets	(328,193)	(309,174)	(139,199)
Normal capital improvements	(88,486)	(90,201)	(53,439)
Construction capital and other improvements	(7,848)	(7,998)	(4,148)
Renovations to existing real estate assets	(30,957)	(21,089)	(11,008)
Development	(38,730)	(70,788)	(53,042)
Distributions from real estate joint ventures	(6)	(15,964)	(9,768)
Contributions to Real Estate Joint Ventures	(32)	0	(268)
Proceeds from disposition of real estate assets	358,017	254,638	128,978
Return (funding) of escrow for future acquisitions	8	24,884	(24,884)
Cash acquired in connection with Colonial merger	0	0	63,454
Net cash used in investing activities	(136,215)	(203,764)	(83,788)
Cash flows from financing activities:
Net change in credit lines	(180,900)	(157,184)	(308,000)
Proceeds from notes payable	395,960	396,855	347,759
Principal payments on notes payable	(279,077)	(260,347)	(11,103)
Payment of deferred financing costs	(7,690)	(4,992)	(6,933)
Repurchase of common stock	(958)	(465)	(702)
Proceeds from issuances of common shares	622	1,042	25,680
Proceeds from Stock Options Exercised	420	12,245	6,212
Distributions to noncontrolling interests	(12,898)	(12,290)	(6,550)
Dividends paid on common shares	(232,079)	(219,158)	(140,697)
Net cash used in financing activities	(316,600)	(244,294)	(94,334)
Net increase (decrease) in cash and cash equivalents	10,906	(62,680)	80,258
Cash and cash equivalents, beginning of period	26,653	89,333	9,075
Cash and cash equivalents, end of period	37,559	26,653	89,333
Supplemental disclosure of cash flow information:
Interest paid	140,811	146,202	83,628
Income Taxes Paid	2,103	1,596	803
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	1,121	1,419	2,519
Accrued construction in progress	5,873	6,626	10,165
Interest capitalized	1,655	1,722	2,089
Marked-to-market adjustment on derivative instruments	2,963	6,159	26,143
Fair value adjustment on debt assumed	0	5,284	86,671
Loan assumption	0	93,049	707,716
Purchase price for Colonial merger	0	0	2,162,876
Limited Partner [Member]
Cash flows from operating activities:
Consolidated net income	(350,745)	(156,277)	(107,544)
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(1,083)	(27)	(35)
Depreciation and amortization	(294,897)	(301,744)	(189,437)
Stock compensation expense	6,147	4,226	2,268
Redeemable stock issued	924	874	692
Amortization of debt premium	(15,515)	(21,282)	(5,870)
(Gain) loss from investments in real estate joint ventures	6	(3,142)	(338)
Loss on debt extinguishment	2,855	2,586	426
Derivative interest (credit) expense	(2,274)	(3,084)	912
Settlement of forward swaps	(1,908)	(3,625)	9,617
Gain on sale of non-depreciable real estate assets	(172)	(350)	0
Gain on sale of depreciable real estate assets excluded from discontinued operations	(189,958)	(42,649)	0
Gain on sale of discontinued operations	0	(5,394)	(65,520)
Net casualty (gain) loss and other settlement proceeds	(473)	476	50
Changes in assets and liabilities:
Restricted cash	2,091	(8,704)	(11,843)
Other assets	12,475	2,013	58,904
Accounts payable	2,578	3,348	48,641
Accrued expenses and other	6,307	7,543	20,135
Security deposits	(1,235)	(1,244)	(166)
Net cash provided by operating activities	463,721	385,378	257,904
Cash flows from investing activities:
Purchases of real estate and other assets	(328,193)	(309,174)	(139,199)
Normal capital improvements	(88,486)	(90,201)	(53,357)
Construction capital and other improvements	(7,848)	(7,998)	(4,148)
Renovations to existing real estate assets	(30,957)	(21,089)	(11,008)
Development	(38,730)	(70,788)	(53,042)
Distributions from real estate joint ventures	(6)	(15,964)	(9,768)
Contributions to Real Estate Joint Ventures	(32)	0	(268)
Proceeds from disposition of real estate assets	358,017	254,638	112,293
Return (funding) of escrow for future acquisitions	8	24,884	(24,884)
Cash acquired in connection with Colonial merger	0	0	63,454
Net cash used in investing activities	(136,215)	(203,764)	(100,391)
Cash flows from financing activities:
Advances from general partner	0	0	17,220
Net change in credit lines	(180,900)	(157,184)	(308,000)
Proceeds from notes payable	395,960	396,855	347,759
Principal payments on notes payable	(279,077)	(260,347)	(11,103)
Payment of deferred financing costs	(7,690)	(4,992)	(6,933)
Repurchase of common units	(958)	(465)	(702)
Proceeds from issuance of common units	622	1,042	25,680
Proceeds from Stock Options Exercised	420	12,245	6,212
Distributions paid on common units	(244,977)	(231,448)	(147,247)
Net cash used in financing activities	(316,600)	(244,294)	(77,114)
Net increase (decrease) in cash and cash equivalents	10,906	(62,680)	80,399
Cash and cash equivalents, beginning of period	26,653	89,333	8,934
Cash and cash equivalents, end of period	37,559	26,653	89,333
Supplemental disclosure of cash flow information:
Interest paid	140,811	146,202	83,628
Income Taxes Paid	2,103	1,596	803
Supplemental disclosure of noncash investing and financing activities:
Accrued construction in progress	5,873	6,626	10,165
Interest capitalized	1,655	1,722	2,089
Marked-to-market adjustment on derivative instruments	2,963	6,159	26,143
Fair value adjustment on debt assumed	0	5,284	86,671
Loan assumption	0	93,049	707,716
Purchase price for Colonial merger	$ 0	$ 0	$ 2,162,876