Consolidated Statements of Income - USD ($) shares in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Resident fees and services		$ 3,234,852,000	$ 2,779,423,000	$ 2,504,731,000
Rental income		1,380,422,000	1,445,871,000	1,648,815,000
Interest income		55,814,000	73,811,000	97,963,000
Other income		29,411,000	17,536,000	29,651,000
Total revenues		4,700,499,000	4,316,641,000	4,281,160,000
Expenses:
Property operating expenses		2,433,017,000	2,083,925,000	1,876,983,000
Depreciation and amortization		950,459,000	921,720,000	901,242,000
Interest expense		526,592,000	484,622,000	521,345,000
General and administrative expenses		126,383,000	122,008,000	155,241,000
Transaction costs		0	0	42,910,000
Loss (gain) on derivatives and financial instruments, net		(4,016,000)	2,284,000	(2,448,000)
Loss (gain) on extinguishment of debt, net		16,097,000	37,241,000	17,214,000
Provision for loan losses		0	62,966,000	10,215,000
Impairment of assets		115,579,000	124,483,000	37,207,000
Other expenses		112,898,000	177,776,000	11,998,000
Total expenses		4,277,009,000	4,017,025,000	3,571,907,000
Income from continuing operations before income taxes and other items		423,490,000	299,616,000	709,253,000
Income tax (expense) benefit		(8,674,000)	(20,128,000)	19,128,000
Income (loss) from unconsolidated entities		(641,000)	(83,125,000)	(10,357,000)
Gain (loss) on real estate dispositions, net		415,575,000	344,250,000	364,046,000
Income from continuing operations		829,750,000	540,613,000	1,082,070,000
Net income		829,750,000	540,613,000	1,082,070,000
Less: Preferred stock dividends		46,704,000	49,410,000	65,406,000
Less: Preferred stock redemption charge		0	9,769,000	0
Less: Net income (loss) attributable to noncontrolling interests	[1]	24,796,000	17,839,000	4,267,000
Net income attributable to common stockholders		$ 758,250,000	$ 463,595,000	$ 1,012,397,000
Average number of common shares outstanding:
Basic (in shares)		373,620	367,237	358,275
Diluted (in shares)		375,250	369,001	360,227
Basic:
Income from continuing operations (in USD per share)		$ 2.22	$ 1.47	$ 3.02
Net income attributable to common stockholders (in USD per share)		2.03	1.26	2.83
Diluted:
Income from continuing operations (in USD per share)		2.21	1.47	3.00
Net income attributable to common stockholders (in USD per share)		$ 2.02	$ 1.26	$ 2.81

[1] Includes amounts attributable to redeemable noncontrolling interests