CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Operating Lease, Lease Income	$ 2,297,442	$ 2,319,666	$ 2,280,963
Management, development and other fees	3,819	4,960	3,572
Total revenue	2,301,261	2,324,626	2,284,535
Expenses:
Cost of Other Property Operating Expense	549,913	515,145	524,993
Property taxes	273,189	252,961	241,563
Interest expense, net	214,151	203,585	220,974
Loss on extinguishment of debt, net	9,333	602	17,492
Depreciation expense	707,331	661,578	631,196
General and administrative expense	60,343	58,042	60,369
Other Nonoperating Expense	12,399	4,991	3,265
Casualty and impairment loss, net	0	0	215
Costs and Expenses, Total	1,826,659	1,696,904	1,700,067
Equity in income of unconsolidated real estate entities	6,422	8,652	15,270
Gain on sale of communities	340,444	166,105	374,976
Gain on other real estate transactions, net	440	439	345
Gain (Loss) on Sale of Other Investments, Net of Marketing and Administrative Costs	2,551	(3,812)	(1,044)
Income before income taxes	824,459	799,106	974,015
Income Tax Expense (Benefit)	3,247	(13,003)	160
Net income	827,706	786,103	974,175
Net (income) loss attributable to noncontrolling interests	(76)	(129)	350
Net income attributable to common stockholders	827,630	785,974	974,525
Other comprehensive income (loss):
(Loss) gain on cash flow hedges	(17,731)	(11,930)	5,132
Cash flow hedge losses reclassified to earnings	(8,984)	(6,571)	(6,143)
Comprehensive income	$ 818,883	$ 780,615	$ 985,800
Earnings per common share - basic:
Net income per common share - basic (in dollars per share)	$ 5.89	$ 5.64	$ 7.05
Earnings per common share - diluted:
Net income per common share - diluted (in dollars per share)	$ 5.89	$ 5.63	$ 7.05