COVID-19 Pandemic (Details)		3 Months Ended	9 Months Ended
	Jul. 26, 2020 USD ($) community	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 09, 2020 USD ($)	Aug. 31, 2020 USD ($) community	Jun. 30, 2020	Mar. 31, 2020 USD ($)	Mar. 20, 2020 USD ($)	Mar. 19, 2020 USD ($)	Jan. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 05, 2018 USD ($)
Unusual or Infrequent Item, or Both [Line Items]
Number of communities owned | community					16
Initial annual minimum rent amount		$ 1,335,335,000	$ 1,335,335,000
Rent reduced the next twelve months		212,133,000	212,133,000
Payments for lease restructuring	$ 119,200,000
Total liquidity		490,700,000	490,700,000
Unrestricted cash and cash equivalents		354,621,000	354,621,000								$ 240,227,000
Marketable securities		136,136,000	136,136,000								$ 68,567,000
CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Facility operating expense		24,500,000	95,100,000
Non-cash asset impairment charges		8,200,000	95,200,000
Employer portion of payroll taxes delayed		50,100,000	50,100,000
Cash made available for Provider Relief Fund			$ 20,000,000,000
Percentage of annual patient care revenue for grant amounts			2.00%
Income recognized from Emergency Fund grant		8,600,000	$ 35,000,000.0
Unrecognized grants		1,100,000	1,100,000
CARES Act | Accelerated and Advance Payment Program
Unusual or Infrequent Item, or Both [Line Items]
Amount received from Accelerated and Advance Payment Program		2,500,000	$ 87,500,000
Percent of Medicare advanced payment						100.00%
CARES Act | The Continuing Appropriations Act, 2021 and Other Extensions Act
Unusual or Infrequent Item, or Both [Line Items]
Recoupment of accelerated/advanced payments start			1 year
CARES Act | The Continuing Appropriations Act, 2021 and Other Extensions Act | Period One
Unusual or Infrequent Item, or Both [Line Items]
Payments for recoupment of accelerated/advanced payments rate			25.00%
Recoupment of accelerated/advanced payments period			11 months
CARES Act | The Continuing Appropriations Act, 2021 and Other Extensions Act | Period Two
Unusual or Infrequent Item, or Both [Line Items]
Payments for recoupment of accelerated/advanced payments rate			50.00%
Recoupment of accelerated/advanced payments period			6 months
Health Care Services and CCRCs | CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Cash made available for Provider Relief Fund			$ 28,900,000
Nursing Facilities | CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Cash made available for Provider Relief Fund			4,600,000
Nursing Facilities, CCRCs Segments | CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Cash made available for Provider Relief Fund			2,600,000
Ventas, Inc
Unusual or Infrequent Item, or Both [Line Items]
Number of communities leased | community	120
Initial annual minimum rent amount	$ 100,000,000
Rent reduced the next twelve months	$ 86,000,000
Payments for lease restructuring			119,200,000
Line of Credit | Fifth Amended and Restated Credit Agreement | Revolving Credit Facility
Unusual or Infrequent Item, or Both [Line Items]
Credit facility, maximum borrowing capacity												$ 250,000,000
Mortgages
Unusual or Infrequent Item, or Both [Line Items]
Debt face amount				$ 156,500,000	$ 191,300,000		$ 73,100,000
Mortgages | Non-Recourse Supplemental Loan
Unusual or Infrequent Item, or Both [Line Items]
Debt face amount				$ 220,500,000	$ 266,900,000		$ 149,300,000	$ 30,000,000.0	$ 29,200,000	$ 238,200,000
Loans Insured or Guaranteed by US Government Authorities | CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Relief received from Provider Relief Fund		$ 2,600,000
Loans Insured or Guaranteed by US Government Authorities | CARES Act | Provider Relief Fund
Unusual or Infrequent Item, or Both [Line Items]
Relief received from Provider Relief Fund			$ 36,100,000