Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Cash flows from financing activities:
Dividends, Preferred Stock, Cash		$ 0	$ 0
Parent Company [Member]
Cash flows from operating activities:
Consolidated net income	$ (224,402)	(350,745)	(156,277)
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(150)	(1,083)	(27)
Depreciation and amortization	(323,283)	(294,897)	(301,744)
Stock compensation expense	11,486	6,147	4,226
Redeemable stock issued	557	924	874
Amortization of debt premium	(9,820)	(15,515)	(21,282)
(Gain) loss from investments in real estate joint ventures	(241)	6	(3,142)
(Gain) loss on debt extinguishment	(56)	2,855	2,586
Derivative interest (credit) expense	(2,806)	(2,274)	(3,084)
Settlement of forward swaps	0	(1,908)	(3,625)
Gain on sale of non-depreciable real estate assets	(2,171)	(172)	(350)
Gain on sale of depreciable real estate assets excluded from discontinued operations	(80,397)	(189,958)	(42,649)
Gain on sale of discontinued operations	0	0	(5,394)
Net casualty (gain) loss and other settlement proceeds	(448)	(473)	476
Changes in assets and liabilities:
Restricted cash	(315)	2,091	(8,704)
Other assets	9,822	12,475	2,013
Accounts payable	24,232	2,578	3,348
Accrued expenses and other	34,458	6,307	7,543
Security deposits	(667)	(1,235)	(1,244)
Net cash provided by operating activities	484,039	463,721	385,378
Cash flows from investing activities:
Purchases of real estate and other assets	(339,186)	(328,193)	(309,174)
Normal capital improvements	(80,392)	(88,486)	(90,201)
Construction capital and other improvements	(7,338)	(7,848)	(7,998)
Renovations to existing real estate assets	(37,316)	(30,957)	(21,089)
Development	(58,931)	(38,730)	(70,788)
Distributions from real estate joint ventures	(1,999)	(6)	(15,964)
Contributions to Real Estate Joint Ventures	0	(32)	0
Proceeds from disposition of real estate assets	296,700	358,017	254,638
Return (funding) of escrow for future acquisitions	(58,259)	8	24,884
Cash acquired in connection with Colonial merger	(427,764)	0	0
Net cash used in investing activities	(710,487)	(136,215)	(203,764)
Cash flows from financing activities:
Net change in credit lines	335,000	(180,900)	(157,184)
Proceeds from notes payable	300,000	395,960	396,855
Principal payments on notes payable	(146,026)	(279,077)	(260,347)
Payment of deferred financing costs	(2,395)	(7,690)	(4,992)
Repurchase of common stock	(2,019)	(958)	(465)
Proceeds from issuances of common shares	291	622	1,042
Proceeds from Stock Options Exercised	0	420	12,245
Dividends, Preferred Stock, Cash	(924)
Distributions to noncontrolling interests	(13,850)	(12,898)	(12,290)
Dividends paid on common shares	(247,652)	(232,079)	(219,158)
Net cash provided by (used in) financing activities	222,425	(316,600)	(244,294)
Net (decrease) increase in cash and cash equivalents	(4,023)	10,906	(62,680)
Cash and cash equivalents, beginning of period	37,559	26,653	89,333
Cash and cash equivalents, end of period	33,536	37,559	26,653
Supplemental disclosure of cash flow information:
Interest paid	144,843	140,811	146,202
Income Taxes Paid	1,582	2,103	1,596
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	902	1,121	1,419
Accrued construction in progress	31,491	5,873	6,626
Interest capitalized	2,073	1,655	1,722
Marked-to-market adjustment on derivative instruments	5,670	2,963	6,159
Fair value adjustment on debt assumed	8,864	0	5,284
Loan assumption	586,744	0	93,049
Limited Partner [Member]
Cash flows from operating activities:
Consolidated net income	(224,402)	(350,745)	(156,277)
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(150)	(1,083)	(27)
Depreciation and amortization	(323,283)	(294,897)	(301,744)
Stock compensation expense	11,486	6,147	4,226
Redeemable stock issued	557	924	874
Amortization of debt premium	(9,820)	(15,515)	(21,282)
(Gain) loss from investments in real estate joint ventures	(241)	6	(3,142)
(Gain) loss on debt extinguishment	(56)	2,855	2,586
Derivative interest (credit) expense	(2,806)	(2,274)	(3,084)
Settlement of forward swaps	0	(1,908)	(3,625)
Gain on sale of non-depreciable real estate assets	(2,171)	(172)	(350)
Gain on sale of depreciable real estate assets excluded from discontinued operations	(80,397)	(189,958)	(42,649)
Gain on sale of discontinued operations	0	0	(5,394)
Net casualty (gain) loss and other settlement proceeds	(448)	(473)	476
Changes in assets and liabilities:
Restricted cash	(315)	2,091	(8,704)
Other assets	9,822	12,475	2,013
Accounts payable	24,232	2,578	3,348
Accrued expenses and other	34,458	6,307	7,543
Security deposits	(667)	(1,235)	(1,244)
Net cash provided by operating activities	484,039	463,721	385,378
Cash flows from investing activities:
Purchases of real estate and other assets	(339,186)	(328,193)	(309,174)
Normal capital improvements	(80,392)	(88,486)	(90,201)
Construction capital and other improvements	(7,338)	(7,848)	(7,998)
Renovations to existing real estate assets	(37,316)	(30,957)	(21,089)
Development	(58,931)	(38,730)	(70,788)
Distributions from real estate joint ventures	(1,999)	(6)	(15,964)
Contributions to Real Estate Joint Ventures	0	(32)	0
Proceeds from disposition of real estate assets	296,700	358,017	254,638
Return (funding) of escrow for future acquisitions	(58,259)	8	24,884
Cash acquired in connection with Colonial merger	(427,764)	0	0
Net cash used in investing activities	(710,487)	(136,215)	(203,764)
Cash flows from financing activities:
Net change in credit lines	335,000	(180,900)	(157,184)
Proceeds from notes payable	300,000	395,960	396,855
Principal payments on notes payable	(146,026)	(279,077)	(260,347)
Payment of deferred financing costs	(2,395)	(7,690)	(4,992)
Repurchase of common units	(2,019)	(958)	(465)
Proceeds from issuance of common units	291	622	1,042
Proceeds from Stock Options Exercised	0	420	12,245
Dividends, Preferred Stock, Cash	(924)	0	0
Distributions paid on common units	(261,502)	(244,977)	(231,448)
Net cash provided by (used in) financing activities	222,425	(316,600)	(244,294)
Net (decrease) increase in cash and cash equivalents	(4,023)	10,906	(62,680)
Cash and cash equivalents, beginning of period	37,559	26,653	89,333
Cash and cash equivalents, end of period	33,536	37,559	26,653
Supplemental disclosure of cash flow information:
Interest paid	144,843	140,811	146,202
Income Taxes Paid	1,582	2,103	1,596
Supplemental disclosure of noncash investing and financing activities:
Accrued construction in progress	31,491	5,873	6,626
Interest capitalized	2,073	1,655	1,722
Marked-to-market adjustment on derivative instruments	5,670	2,963	6,159
Fair value adjustment on debt assumed	8,864	0	5,284
Loan assumption	586,744	0	93,049
Purchase Price Post	$ 4,006,586	$ 0	$ 0