Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Limited Partner [Member]
Cash flows from operating activities:
Consolidated net income	$ 107,544,000	$ 109,040,000	$ 50,588,000
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(35,000)	(31,000)	0
Depreciation and amortization	192,500,000	131,642,000	118,765,000
Stock compensation expense	2,268,000	2,233,000	4,035,000
Exercise of stock options	6,212,000	0	0
Redeemable stock issued	692,000	546,000	494,000
Amortization of debt premium	(8,933,000)	(767,000)	(360,000)
(Gain) loss from investments in real estate joint ventures	(338,000)	223,000	593,000
Loss on debt extinguishment	426,000	1,012,000	755,000
Derivative interest expense	912,000	823,000	543,000
Settlement of forward swaps	9,617,000	0	0
Gain on sale of non-depreciable assets	0	45,000	1,084,000
Gain on sale of discontinued operations	(65,520,000)	(41,635,000)	(12,799,000)
Net casualty loss (gain) and other settlement proceeds	50,000	(42,000)	619,000
Changes in assets and liabilities:
Restricted cash	(11,843,000)	554,000	151,000
Other assets	58,904,000	(1,430,000)	(1,265,000)
Accounts payable	(48,641,000)	2,468,000	264,000
Accrued expenses and other	20,135,000	4,738,000	8,557,000
Security deposits	166,000	355,000	(372,000)
Net cash provided by operating activities	264,116,000	209,684,000	169,484,000
Cash flows from investing activities:
Purchases of real estate and other assets	(139,199,000)	(312,001,000)	(362,745,000)
Normal capital improvements	(53,357,000)	(46,775,000)	(51,875,000)
Construction capital and other improvements	(4,148,000)	(3,636,000)	0
Renovations to existing real estate assets	(11,008,000)	(14,420,000)	(12,680,000)
Development	(53,042,000)	(73,991,000)	(38,153,000)
Distributions from real estate joint ventures	9,768,000	12,164,000	1,402,000
Contributions to real estate joint ventures	(268,000)	(218,000)	(1,510,000)
Proceeds from disposition of real estate assets	112,293,000	110,101,000	23,837,000
Funding of escrow for future acquisitions	(24,884,000)	0	0
Cash acquired in connection with Colonial merger	63,454,000	0	0
Net cash used in investing activities	(100,391,000)	(328,776,000)	(441,724,000)
Cash flows from financing activities:
Advances from general partner	17,220,000	812,000	2,355,000
Net change in credit lines	(308,000,000)	(320,064,000)	(121,533,000)
Proceeds from notes payable	347,759,000	325,000,000	285,350,000
Principal payments on notes payable	(11,103,000)	(12,944,000)	(13,895,000)
Payment of deferred financing costs	(6,933,000)	(3,616,000)	(4,641,000)
Repurchase of common units	702,000	1,990,000	2,548,000
Proceeds from issuance of common units	25,680,000	196,325,000	235,739,000
Distributions paid on common units	147,247,000	112,697,000	97,227,000
Net cash (used in) provided by financing activities	(83,326,000)	70,826,000	283,600,000
Net increase (decrease) in cash and cash equivalents	80,399,000	(48,266,000)	11,360,000
Cash and cash equivalents, beginning of period	8,934,000	57,200,000	45,840,000
Cash and cash equivalents, end of period	89,333,000	8,934,000	57,200,000
Supplemental disclosure of cash flow information:
Income Taxes Paid	803,000	727,000	623,000
Interest paid	83,628,000	60,950,000	59,655,000
Supplemental disclosure of noncash investing and financing activities:
Accrued construction in progress	10,165,000	3,449,000	8,599,000
Interest capitalized	2,089,000	2,318,000	1,156,000
Marked-to-market adjustment on derivative instruments	26,143,000	10,875,000	13,146,000
Reclassification of redeemable stock to liabilities	0	0	152,000
Fair value adjustment on debt assumed	86,671,000	2,578,000	0
Loan assumption	707,716,000	30,290,000	0
Purchase price for Colonial merger	2,162,876,000	0	0
Parent Company [Member]
Cash flows from operating activities:
Consolidated net income	119,279,000	109,825,000	51,231,000
Adjustments to reconcile net income to net cash provided by operating activities:
Retail revenue accretion	(35,000)	(31,000)	0
Depreciation and amortization	192,736,000	132,195,000	119,329,000
Stock compensation expense	2,268,000	2,233,000	5,519,000
Exercise of stock options	6,212,000	0	0
Redeemable stock issued	692,000	546,000	494,000
Amortization of debt premium	(8,933,000)	(767,000)	(360,000)
(Gain) loss from investments in real estate joint ventures	(338,000)	223,000	593,000
Loss on debt extinguishment	426,000	1,012,000	755,000
Derivative interest expense	911,000	827,000	543,000
Settlement of forward swaps	9,617,000	0	0
Gain on sale of non-depreciable assets	0	45,000	910,000
Gain on sale of discontinued operations	(76,844,000)	(41,635,000)	(12,799,000)
Net casualty loss (gain) and other settlement proceeds	50,000	(42,000)	619,000
Changes in assets and liabilities:
Restricted cash	(11,844,000)	554,000	152,000
Other assets	59,032,000	(1,395,000)	(1,356,000)
Accounts payable	(48,674,000)	2,495,000	265,000
Accrued expenses and other	19,890,000	4,613,000	8,596,000
Security deposits	147,000	359,000	(383,000)
Net cash provided by operating activities	264,592,000	210,967,000	172,288,000
Cash flows from investing activities:
Purchases of real estate and other assets	(139,199,000)	(312,001,000)	(362,745,000)
Normal capital improvements	(53,439,000)	(47,222,000)	(46,947,000)
Construction capital and other improvements	(4,148,000)	(3,636,000)	(5,190,000)
Renovations to existing real estate assets	(11,008,000)	(14,420,000)	(12,680,000)
Development	(53,042,000)	(73,991,000)	(38,153,000)
Distributions from real estate joint ventures	9,768,000	12,164,000	1,402,000
Contributions to real estate joint ventures	(268,000)	(218,000)	(1,510,000)
Proceeds from disposition of real estate assets	128,978,000	110,101,000	23,663,000
Funding of escrow for future acquisitions	(24,884,000)	0	0
Cash acquired in connection with Colonial merger	63,454,000	0	0
Net cash used in investing activities	(83,788,000)	(329,223,000)	(442,160,000)
Cash flows from financing activities:
Net change in credit lines	(308,000,000)	(320,064,000)	(121,533,000)
Proceeds from notes payable	347,759,000	325,000,000	285,350,000
Principal payments on notes payable	(11,103,000)	(12,944,000)	(13,895,000)
Payment of deferred financing costs	(6,933,000)	(3,616,000)	(4,641,000)
Repurchase of common stock	(702,000)	(1,990,000)	(2,548,000)
Proceeds from issuances of common shares	25,680,000	196,325,000	235,741,000
Distributions to noncontrolling interests	(6,550,000)	(4,948,000)	(5,199,000)
Dividends paid on common shares	(140,697,000)	(107,749,000)	(92,028,000)
Net cash (used in) provided by financing activities	(100,546,000)	70,014,000	281,247,000
Net increase (decrease) in cash and cash equivalents	80,258,000	(48,242,000)	11,375,000
Cash and cash equivalents, beginning of period	9,075,000	57,317,000	45,942,000
Cash and cash equivalents, end of period	89,333,000	9,075,000	57,317,000
Supplemental disclosure of cash flow information:
Income Taxes Paid	803,000	727,000	623,000
Interest paid	83,628,000	60,950,000	59,655,000
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	2,519,000	3,459,000	3,069,000
Accrued construction in progress	10,165,000	3,449,000	8,599,000
Interest capitalized	2,089,000	2,318,000	1,156,000
Marked-to-market adjustment on derivative instruments	26,143,000	10,875,000	13,084,000
Reclassification of redeemable stock to liabilities	0	0	152,000
Fair value adjustment on debt assumed	86,671,000	2,578,000	0
Loan assumption	707,716,000	30,290,000	0
Purchase price for Colonial merger	2,162,876,000	0	0
Series of Individually Immaterial Business Acquisitions | Parent Company [Member]
Cash flows from investing activities:
Purchases of real estate and other assets	$ 139,200,000