Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Document Fiscal Year Focus			2018
Other expense (income):
Provision for impairment, net of tax	$ 2,974	$ 0	$ 3,348	$ 0
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	1,123	4,366	1,219	4,781
Parent Company [Member]
Revenues:
Minimum rent	208,827	195,992	410,219	337,232
Percentage rent	1,196	1,456	5,068	4,362
Revenue from Contract with Customer, Including Assessed Tax	64,502	57,256	128,773	102,535
Property Management Fee Revenue	6,887	6,601	14,045	13,307
Total revenues	281,412	261,305	558,105	457,436
Operating expenses:
Depreciation and amortization	89,105	92,230	177,629	152,284
Operating and maintenance	41,851	36,105	84,367	65,868
General and administrative	16,776	16,746	34,382	34,419
Real estate taxes	31,541	28,871	61,967	50,321
Other operating expenses (note 2)	2,799	6,862	4,432	78,425
Total operating expenses	182,072	180,814	362,777	381,317
Other expense (income):
Interest expense, net	38,074	35,407	74,859	62,606
Provision for impairment, net of tax	12,533	0	28,587	0
Gain (Loss) on Extinguishment of Debt	11,010	12,404	11,172	12,404
Marketable Securities, Gain (Loss), Excluding Other-than-temporary Impairment Loss	(569)	(887)	(602)	(1,984)
Nonoperating Income (Expense)	61,048	46,924	114,016	73,026
Income from operations before equity in income of investments in real estate partnerships	38,292	33,567	81,312	3,093
Equity in income of investments in real estate partnerships	9,174	12,240	19,523	21,583
Income from operations	47,466	45,807	100,835	24,676
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	1,123	4,366	1,219	4,781
Net income	48,589	50,173	102,054	29,457
Noncontrolling interests:
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable	100	104	212	85
Limited partners’ interests in consolidated partnerships	(648)	(576)	(1,342)	(1,247)
Income attributable to noncontrolling interests	(748)	(680)	(1,554)	(1,332)
Net income attributable to the Company	47,841	49,493	100,500	28,125
Preferred stock dividends and issuance costs	0	(1,125)	0	(12,981)
Net Income (Loss) Available to Common Stockholders, Basic	$ 47,841	$ 48,368	$ 100,500	$ 15,144
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.28	$ 0.28	$ 0.59	$ 0.10
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.28	$ 0.28	$ 0.59	$ 0.10
Partnership Interest [Member]
Revenues:
Minimum rent	$ 208,827	$ 195,992	$ 410,219	$ 337,232
Percentage rent	1,196	1,456	5,068	4,362
Revenue from Contract with Customer, Including Assessed Tax	64,502	57,256	128,773	102,535
Property Management Fee Revenue	6,887	6,601	14,045	13,307
Total revenues	281,412	261,305	558,105	457,436
Operating expenses:
Depreciation and amortization	89,105	92,230	177,629	152,284
Operating and maintenance	41,851	36,105	84,367	65,868
General and administrative	16,776	16,746	34,382	34,419
Real estate taxes	31,541	28,871	61,967	50,321
Other operating expenses (note 2)	2,799	6,862	4,432	78,425
Total operating expenses	182,072	180,814	362,777	381,317
Other expense (income):
Interest expense, net	38,074	35,407	74,859	62,606
Provision for impairment, net of tax	12,533	0	28,587	0
Gain (Loss) on Extinguishment of Debt	11,010	12,404	11,172	12,404
Marketable Securities, Gain (Loss), Excluding Other-than-temporary Impairment Loss	(569)	(887)	(602)	(1,984)
Nonoperating Income (Expense)	61,048	46,924	114,016	73,026
Income from operations before equity in income of investments in real estate partnerships	38,292	33,567	81,312	3,093
Equity in income of investments in real estate partnerships	9,174	12,240	19,523	21,583
Income from operations	47,466	45,807	100,835	24,676
Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes	1,123	4,366	1,219	4,781
Net income	48,589	50,173	102,054	29,457
Noncontrolling interests:
Limited partners’ interests in consolidated partnerships	(648)	(576)	(1,342)	(1,247)
Income attributable to noncontrolling interests	(648)	(576)	(1,342)	(1,247)
Net income attributable to the Company	47,941	49,597	100,712	28,210
Distributions Paid To Preferred Unit Holders	0	(1,125)	0	(12,981)
Net income attributable to common unit holders	$ 47,941	$ 48,472	$ 100,712	$ 15,229
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.28	$ 0.28	$ 0.59	$ 0.10
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.28	$ 0.28	$ 0.59	$ 0.10