Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 115,680	$ 130,099
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	254,105	247,266
Loss on sale of depreciable real estate assets	27	13
Loss (gain) on sale of non-depreciable real estate assets	371	(9,260)
Loss (gain) on embedded derivative in preferred shares	15,945	(4,070)
Stock compensation expense	8,150	8,237
Amortization of debt issuance costs, discounts and premiums	2,290	3,468
Net change in operating accounts and other operating activities	(6,953)	(7,286)
Net cash provided by operating activities	389,615	368,467
Cash flows from investing activities:
Purchases of real estate and other assets	(5,004)	(19,596)
Capital improvements, development and other	(191,850)	(133,354)
Distributions from real estate joint ventures	84	184
Contributions to affiliates	(1,725)	(2,700)
Proceeds from disposition of real estate assets	660	14,640
Net cash used in investing activities	(197,835)	(140,826)
Cash flows from financing activities:
Proceeds from revolving credit facility	180,000	545,000
Repayments of revolving credit facility	(180,000)	(1,085,000)
Net proceeds from commercial paper	20,000	367,000
Proceeds from notes payable		490,435
Principal payments on notes payable	(3,483)	(303,672)
Payment of deferred financing costs	(31)	(9,048)
Distributions to noncontrolling interests	(8,126)	(7,886)
Distributions paid on common shares/units	(228,618)	(218,758)
Distributions paid on preferred shares/units	(1,844)	(1,844)
Net change in other financing activities	(4,625)	2,143
Net cash used in financing activities	(226,727)	(221,630)
Net (decrease) increase in cash, cash equivalents and restricted cash	(34,947)	6,011
Cash, cash equivalents and restricted cash, beginning of period	70,541	51,673
Cash, cash equivalents and restricted cash, end of period	35,594	57,684
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	19,667	40,972
Restricted cash	15,927	16,712
Cash, cash equivalents and restricted cash, end of period	35,594	57,684
Supplemental disclosure of cash flow information:
Interest paid	84,623	84,972
Income taxes paid	120	2,452
Supplemental disclosure of noncash investing and financing activities:
Conversion of OP Units to shares of common stock	450	1,157
Accrued construction in progress	18,991	21,063
Interest capitalized	3,019	1,093
Limited Partner [Member]
Cash flows from operating activities:
Net income	115,680	130,099
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	254,105	247,266
Loss on sale of depreciable real estate assets	27	13
Loss (gain) on sale of non-depreciable real estate assets	371	(9,260)
Loss (gain) on embedded derivative in preferred shares	15,945	(4,070)
Stock compensation expense	8,150	8,237
Amortization of debt issuance costs, discounts and premiums	2,290	3,468
Net change in operating accounts and other operating activities	(6,953)	(7,286)
Net cash provided by operating activities	389,615	368,467
Cash flows from investing activities:
Purchases of real estate and other assets	(5,004)	(19,596)
Capital improvements, development and other	(191,850)	(133,354)
Distributions from real estate joint ventures	84	184
Contributions to affiliates	(1,725)	(2,700)
Proceeds from disposition of real estate assets	660	14,640
Net cash used in investing activities	(197,835)	(140,826)
Cash flows from financing activities:
Proceeds from revolving credit facility	180,000	545,000
Repayments of revolving credit facility	(180,000)	(1,085,000)
Net proceeds from commercial paper	20,000	367,000
Proceeds from notes payable		490,435
Principal payments on notes payable	(3,483)	(303,672)
Payment of deferred financing costs	(31)	(9,048)
Distributions paid on common shares/units	(236,744)	(226,644)
Distributions paid on preferred shares/units	(1,844)	(1,844)
Net change in other financing activities	(4,625)	2,143
Net cash used in financing activities	(226,727)	(221,630)
Net (decrease) increase in cash, cash equivalents and restricted cash	(34,947)	6,011
Cash, cash equivalents and restricted cash, beginning of period	70,541	51,673
Cash, cash equivalents and restricted cash, end of period	35,594	57,684
Reconciliation of cash, cash equivalents and restricted cash:
Cash and cash equivalents	19,667	40,972
Restricted cash	15,927	16,712
Cash, cash equivalents and restricted cash, end of period	35,594	57,684
Supplemental disclosure of cash flow information:
Interest paid	84,623	84,972
Income taxes paid	120	2,452
Supplemental disclosure of noncash investing and financing activities:
Accrued construction in progress	18,991	21,063
Interest capitalized	$ 3,019	$ 1,093