Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Parent Company [Member]
Cash flows from operating activities:
Consolidated net income	$ 93,438	$ 208,550
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(110)	(820)
Depreciation and amortization	151,114	147,765
Stock compensation expense	3,958	2,763
Redeemable stock issued	282	560
Amortization of debt premium	(5,096)	(8,517)
(Gain) loss from investments in real estate joint ventures	(27)	6
Loss on debt extinguishment	0	2,785
Derivative interest (credit) expense	(1,295)	(1,021)
Gain on sale of non-depreciable real estate assets	(2,170)	(172)
Gain on sale of depreciable real estate assets excluded from discontinued operations	(823)	(135,410)
Net casualty loss and other settlement proceeds	(813)	(490)
Changes in assets and liabilities:
Restricted cash	951	1,720
Other assets	4,130	8,562
Accounts payable	(1,542)	(344)
Accrued expenses and other	(7,567)	(1,204)
Security deposits	702	1,109
Net cash provided by operating activities	238,216	226,530
Cash flows from investing activities:
Purchases of real estate and other assets	(130,597)	(161,892)
Normal capital improvements	(44,417)	(48,099)
Construction capital and other improvements	(3,288)	(3,873)
Renovations to existing real estate assets	(17,719)	(12,747)
Development	(29,156)	(14,420)
Distributions from real estate joint ventures	1,793	6
Contributions to Real Estate Joint Ventures	0	(30)
Proceeds from disposition of real estate assets	38,001	238,849
(Funding) return of escrow for future acquisitions	0	(26,945)
Net cash (used in) provided by investing activities	(185,383)	(29,151)
Cash flows from financing activities:
Net change in credit lines	105,000	(16,115)
Principal payments on notes payable	(37,261)	(55,199)
Payment of deferred financing costs	(141)	(178)
Repurchase of common stock	(1,742)	(945)
Proceeds from issuances of common shares	628	184
Proceeds from Stock Options Exercised	0	420
Distributions to noncontrolling interests	(6,823)	(6,443)
Dividends paid on common shares	(123,774)	(115,726)
Net cash used in financing activities	(64,113)	(194,002)
Net (decrease) increase in cash and cash equivalents	(11,280)	3,377
Cash and cash equivalents, beginning of period	37,559	26,653
Cash and cash equivalents, end of period	26,279	30,030
Supplemental disclosure of cash flow information:
Interest paid	71,092	71,596
Income Taxes Paid	1,544	2,051
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	158	184
Accrued construction in progress	10,781	11,165
Interest capitalized	708	964
Marked-to-market adjustment on derivative instruments	(1,407)	2,484
Limited Partner [Member]
Cash flows from operating activities:
Consolidated net income	93,438	208,550
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(110)	(820)
Depreciation and amortization	151,114	147,765
Stock compensation expense	3,958	2,763
Redeemable stock issued	282	560
Amortization of debt premium	(5,096)	(8,517)
(Gain) loss from investments in real estate joint ventures	(27)	6
Loss on debt extinguishment	0	2,785
Derivative interest (credit) expense	(1,295)	(1,021)
Gain on sale of non-depreciable real estate assets	(2,170)	(172)
Gain on sale of depreciable real estate assets excluded from discontinued operations	(823)	(135,410)
Net casualty loss and other settlement proceeds	(813)	(490)
Changes in assets and liabilities:
Restricted cash	951	1,720
Other assets	4,130	8,562
Accounts payable	(1,542)	(344)
Accrued expenses and other	(7,567)	(1,204)
Security deposits	702	1,109
Net cash provided by operating activities	238,216	226,530
Cash flows from investing activities:
Purchases of real estate and other assets	(130,597)	(161,892)
Normal capital improvements	(44,417)	(48,099)
Construction capital and other improvements	(3,288)	(3,873)
Renovations to existing real estate assets	(17,719)	(12,747)
Development	(29,156)	(14,420)
Distributions from real estate joint ventures	1,793	6
Contributions to Real Estate Joint Ventures	0	(30)
Proceeds from disposition of real estate assets	38,001	238,849
(Funding) return of escrow for future acquisitions	0	(26,945)
Net cash (used in) provided by investing activities	(185,383)	(29,151)
Cash flows from financing activities:
Net change in credit lines	105,000	(16,115)
Principal payments on notes payable	(37,261)	(55,199)
Payment of deferred financing costs	(141)	(178)
Repurchase of common units	(1,742)	(945)
Proceeds from issuances of common units	628	184
Proceeds from Stock Options Exercised	0	420
Distributions paid on common units	(130,597)	(122,169)
Net cash used in financing activities	(64,113)	(194,002)
Net (decrease) increase in cash and cash equivalents	(11,280)	3,377
Cash and cash equivalents, beginning of period	37,559	26,653
Cash and cash equivalents, end of period	26,279
Supplemental disclosure of cash flow information:
Interest paid	71,092	71,596
Income Taxes Paid	1,544	2,051
Supplemental disclosure of noncash investing and financing activities:
Accrued construction in progress	10,781	11,165
Interest capitalized	708	964
Marked-to-market adjustment on derivative instruments	$ (1,407)	$ 2,484