Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Parent Company [Member]
Cash flows from operating activities:
Consolidated net income	$ 167,505	$ 212,529
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	(369,223)	(374,947)
(Gain) Loss on sale of depreciable real estate assets excluded from discontinued operations	21	(59,045)
Gain on sale of non-depreciable real estate assets	(3,870)	(42)
Stock compensation expense	9,877	8,431
Amortization of debt premium	(4,318)	(8,035)
Proceeds from Other Operating Activities	62,618	28,671
Net cash provided by operating activities	601,056	557,456
Cash flows from investing activities:
Purchases of real estate and other assets	(112,656)	(63,774)
Normal capital improvements	(192,520)	(268,423)
Contributions to Real Estate Joint Ventures	(1,500)	(750)
Proceeds from disposition of real estate assets	18,918	89,857
Net cash (used in) provided by investing activities	(287,758)	(243,090)
Cash flows from financing activities:
Proceeds from Lines of Credit	780,000	580,000
Repayments of Lines of Credit	820,000	820,000
Proceeds from notes payable	397,612	597,480
Principal payments on notes payable	(346,239)	(345,053)
Payment of deferred financing costs	3,741	5,355
Repurchase of common stock	(2,912)	(4,782)
Payment for Debt Extinguishment or Debt Prepayment Cost	(3)	(1,585)
Proceeds from issuances of common shares	488	1,007
Proceeds from Stock Options Exercised	916	432
Distributions to noncontrolling interests	(11,286)	(10,999)
Dividends paid on common shares	(314,834)	(296,441)
Dividends, Preferred Stock, Cash	(2,766)	(2,766)
Net cash used in financing activities	(322,765)	(308,062)
Net (decrease) increase in cash and cash equivalents	(9,467)	6,304
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning	88,867	121,800
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending	79,400	128,104
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	46,139	47,851
Restricted Cash	33,261	80,253
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending	79,400	128,104
Supplemental disclosure of cash flow information:
Interest paid	111,439	123,735
Income Taxes Paid	2,746	2,256
Supplemental disclosure of noncash investing and financing activities:
Conversion of units to shares of common stock	4,282	1,133
Accrued construction in progress	19,476	15,787
Interest capitalized	1,640	5,884
Marked To Market Adjustment On Derivative Instruments	7,956	12,035
Limited Partner [Member]
Cash flows from operating activities:
Consolidated net income	167,505	212,529
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	(369,223)	(374,947)
(Gain) Loss on sale of depreciable real estate assets excluded from discontinued operations	21	(59,045)
Gain on sale of non-depreciable real estate assets	(3,870)	(42)
Stock compensation expense	9,877	8,431
Amortization of debt premium	(4,318)	(8,035)
Proceeds from Other Operating Activities	62,618	28,671
Net cash provided by operating activities	601,056	557,456
Cash flows from investing activities:
Purchases of real estate and other assets	(112,656)	(63,774)
Normal capital improvements	(192,520)	(268,423)
Contributions to Real Estate Joint Ventures	(1,500)	(750)
Proceeds from disposition of real estate assets	18,918	89,857
Net cash (used in) provided by investing activities	(287,758)	(243,090)
Cash flows from financing activities:
Proceeds from Lines of Credit	780,000	580,000
Repayments of Lines of Credit	820,000	820,000
Proceeds from notes payable	397,612	597,480
Principal payments on notes payable	(346,239)	(345,053)
Payment of deferred financing costs	3,741	5,355
Repurchase of common units	(2,912)	(4,782)
Payment for Debt Extinguishment or Debt Prepayment Cost	(3)	(1,585)
Proceeds from issuances of common units	488	1,007
Proceeds from Stock Options Exercised	916	432
Distributions paid on common units	(326,120)	(307,440)
Dividends, Preferred Stock, Cash	(2,766)	(2,766)
Net cash used in financing activities	(322,765)	(308,062)
Net (decrease) increase in cash and cash equivalents	(9,467)	6,304
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Beginning	88,867	121,800
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending	79,400	128,104
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents	46,139	47,851
Restricted Cash	33,261	80,253
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Ending	79,400	128,104
Supplemental disclosure of cash flow information:
Interest paid	111,439	123,735
Income Taxes Paid	2,746	2,256
Supplemental disclosure of noncash investing and financing activities:
Accrued construction in progress	19,476	15,787
Interest capitalized	1,640	5,884
Marked To Market Adjustment On Derivative Instruments	$ 7,956	$ 12,035