Acquisitions, Dispositions and Other Transactions - Ventas Lease Restructuring (Details)		3 Months Ended	9 Months Ended
	Jul. 26, 2020 USD ($) community extension_option $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($)	Dec. 31, 2019 $ / shares
Business Acquisition [Line Items]
Initial annual minimum rent amount		$ 1,335,335,000	$ 1,335,335,000
Repayments of lines of credit			$ 166,381,000	$ 0
Number of shares authorized to be purchased | shares		16,300,000	16,300,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01		$ 0.01
Payments for lease restructuring	$ 119,200,000
Ventas, Inc
Business Acquisition [Line Items]
Number of communities leased | community	120
Initial annual minimum rent amount	$ 100,000,000
Reduction in rent amount to be paid	$ 83,000,000
Annual escalator rate	3.00%
Number of extensions | extension_option	2
Term of extensions	10 years
Capital expenditures incurred but not yet paid	$ 37,800,000
Minimum tangible net worth	600,000,000.0
Control fees	$ 25,000,000.0
Number of owned communities transferred | community	5
Extinguishment of debt	$ 78,400,000
Cash payments to related party	115,000,000.0
Deposit disbursements	42,400,000
Repayments of lines of credit	4,200,000
Operating lease obligations		$ 370,000,000.0
Assets under leases		$ 159,500,000
Payments for lease restructuring			$ 119,200,000
Community Level Basis | Ventas, Inc
Business Acquisition [Line Items]
Escrow amount	1,500
Aggregate Community Basis | Ventas, Inc
Business Acquisition [Line Items]
Escrow amount	$ 3,600
Disbursement Multiplier | Ventas, Inc
Business Acquisition [Line Items]
Annual escalator rate	50.00%
Multiplier Percentage | Ventas, Inc
Business Acquisition [Line Items]
Annual escalator rate	4.50%
Unsecured Debt | Ventas, Inc
Business Acquisition [Line Items]
Debt face amount	$ 45,000,000.0
Interest rate, stated percentage	9.00%
Interest rate percentage increase per anniversary	0.50%
The Warrant | Ventas, Inc
Business Acquisition [Line Items]
Number of shares authorized to be purchased | shares	16,300,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.01
Share price (in usd per share) | $ / shares	$ 3.00
Shares voting percentage ownership cap	9.60%
Value of warrants issued	$ 22,900,000