CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue:
Rental and other income	$ 2,280,963	$ 2,154,481	$ 2,039,656
Management, development and other fees	3,572	4,147	5,599
Total revenue	2,284,535	2,158,628	2,045,255
Expenses:
Operating expenses, excluding property taxes	528,997	503,946	478,437
Property taxes	241,563	221,375	204,837
Interest expense, net	220,974	199,661	187,510
Loss on extinguishment of debt, net	17,492	25,472	7,075
Depreciation expense	631,196	584,150	531,434
General and administrative expense	56,365	50,673	45,771
Expensed transaction, development and other pursuit costs, net of recoveries	4,309	2,736	9,922
Casualty and impairment loss (gain), net	215	6,250	(3,935)
Total expenses	1,701,111	1,594,263	1,461,051
Equity in income of unconsolidated real estate entities	15,270	70,744	64,962
Gain on sale of communities	374,976	252,599	374,623
Gain (loss) on other real estate transactions, net	345	(10,907)	10,224
Income before income taxes	974,015	876,801	1,034,013
Income tax (benefit) expense	(160)	141	305
Net income	974,175	876,660	1,033,708
Net loss attributable to noncontrolling interests	350	261	294
Net income attributable to common stockholders	974,525	876,921	1,034,002
Other comprehensive income (loss):
Gain (loss) on cash flow hedges	5,132	(13,979)	(5,556)
Cash flow hedge losses reclassified to earnings	(6,143)	(7,070)	(6,433)
Comprehensive income	$ 985,800	$ 870,012	$ 1,034,879
Earnings per common share - basic:
Net income per common share - basic (in dollars per share)	$ 7.05	$ 6.36	$ 7.53
Earnings per common share - diluted:
Net income per common share - diluted (in dollars per share)	$ 7.05	$ 6.35	$ 7.52