Organization, Basis of Presentation, and Significant Accounting Policies (Details 2) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) community	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Accounting Policies [Abstract]
Minimum distribution of adjusted taxable income for deducting dividends from federally taxable income (as a percent)									90.00%
Minimum distribution of REIT taxable income for federal income tax exemption (as a percent)									100.00%
Accounting Policies [Line Items]
Right of use lease assets	$ 103,063								$ 103,063
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	0				$ 0				0	$ 0
Excise and sales taxes									0	0	$ 0
Excise tax refund	0				0				0	0	0
Income Tax Expense (Benefit)									13,003	(160)	141
Casualty and impairment loss, net									0	215	6,250
Impairment of investment in unconsolidated entities									$ 0	0	0
Deferred Financing Costs
Number Of Communities Sold With Deferred Tax Obligations | community									2
Operating Lease, Liability	120,261								$ 120,261
Reconciliation of Income from Book Basis to Tax Basis Adjustment
Net income attributable to common stockholders	167,650	$ 279,677	$ 168,281	$ 170,366	385,734	$ 192,486	$ 254,662	$ 141,643	785,974	974,525	876,921
GAAP gain on sale of communities in excess of tax gain									(108,962)	(192,722)	(86,661)
Depreciation/amortization timing differences on real estate									(5,619)	(15,590)	(3,642)
Amortization of debt/mark to market interest									(594)	(2,276)	(18,096)
Tax compensation expense less than GAAP									4,738	13,126	20,243
Other adjustments									22,637	19,617	(392)
Taxable net income									$ 698,174	$ 796,680	$ 788,373
Tax components of common stock dividends declared
Ordinary income (as a percent)									96.00%	76.00%	75.00%
20% capital gain (as a percent)									3.00%	11.00%	18.00%
Capital gain tax rate (as a percent)									20.00%	20.00%	20.00%
Unrecaptured 1250 gain (as a percent)									1.00%	13.00%	7.00%
Unsecured notes
Deferred Financing Costs
Accumulated amortization of deferred finance costs	25,995				20,564				$ 25,995	$ 20,564
Secured notes
Deferred Financing Costs
Accumulated amortization of deferred finance costs	1,784				2,044				1,784	2,044
Variable rate unsecured credit facility
Deferred Financing Costs
Accumulated amortization of deferred finance costs	11,815				$ 10,108				11,815	10,108
TRS Disposed Communities [Member]
Income Tax Disclosure [Abstract]
Income Tax Expense (Benefit)									7,221
Land
Income Tax Disclosure [Abstract]
Casualty and impairment loss, net									0	$ 826	$ 9,350
Development Communities | The Park Loggia [Member]
Income Tax Disclosure [Abstract]
Income Tax Expense (Benefit)									5,782
Casualty and impairment loss, net									0
Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Right of use lease assets	$ 122,276								$ 122,276
Deferred Financing Costs
Operating Lease, Liability												$ 122,276
Minimum | Buildings and Building Improvements
Accounting Policies [Line Items]
Estimated useful life of buildings and improvements (in years)									7 years