Borrowings - Schedule of Borrowings (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($) Investment property debt_instrument	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Long-term debt	$ 1,447,523
Number of debt instruments | Investment	1
Watermark Fountains Portfolio
Debt Instrument [Line Items]
Number of healthcare real estate properties | property	14
Winterfell
Debt Instrument [Line Items]
Number of healthcare real estate properties | property	32
Mortgage notes payable, net
Debt Instrument [Line Items]
Principal Amount	$ 1,447,523	$ 1,455,413
Long-term debt	$ 1,426,509	1,431,922
Mortgage notes payable, net | Rochester Portfolio
Debt Instrument [Line Items]
Number of debt instruments | debt_instrument	7
Number of healthcare real estate properties | property	7
Mortgage notes payable, net | Arbors Portfolio
Debt Instrument [Line Items]
Number of debt instruments | debt_instrument	4
Number of healthcare real estate properties | property	4
Mortgage notes payable, net | Winterfell
Debt Instrument [Line Items]
Number of debt instruments | debt_instrument	32
Mortgage notes payable, net | Avamere Portfolio
Debt Instrument [Line Items]
Number of debt instruments | debt_instrument	5
Number of healthcare real estate properties | property	5
Mortgage notes payable, net | Non-Recourse
Debt Instrument [Line Items]
Principal Amount	$ 1,443,609	1,451,720
Long-term debt	$ 1,422,595	1,428,229
Mortgage notes payable, net | Non-Recourse | Arbors Portfolio
Debt Instrument [Line Items]
Lease obligation interest rate	3.99%
Principal Amount	$ 88,438	89,026
Long-term debt	$ 87,547	88,020
Mortgage notes payable, net | Non-Recourse | Watermark Fountains Portfolio
Debt Instrument [Line Items]
Lease obligation interest rate	3.92%
Principal Amount	$ 389,886	392,269
Long-term debt	$ 388,509	390,508
Mortgage notes payable, net | Non-Recourse | Watermark Fountains Portfolio 2
Debt Instrument [Line Items]
Lease obligation interest rate	5.56%
Principal Amount	$ 73,880	74,208
Long-term debt	$ 73,522	73,750
Number of healthcare real estate properties | property	7
Mortgage notes payable, net | Non-Recourse | Winterfell
Debt Instrument [Line Items]
Lease obligation interest rate	4.17%
Principal Amount	$ 628,303	632,024
Long-term debt	$ 612,225	614,415
Mortgage notes payable, net | Non-Recourse | Avamere Portfolio
Debt Instrument [Line Items]
Lease obligation interest rate	4.66%
Principal Amount	$ 70,996	71,464
Long-term debt	70,492	70,922
Mortgage notes payable, net | Denver, CO Non-recourse | Denver, CO
Debt Instrument [Line Items]
Principal Amount	20,424	20,547
Long-term debt	$ 20,398	20,500
Mortgage notes payable, net | Denver, CO Non-recourse | Denver, CO | LIBOR
Debt Instrument [Line Items]
Interest rate (percentage)	2.92%
Mortgage notes payable, net | Frisco, TX Non-recourse | Frisco, TX
Debt Instrument [Line Items]
Principal Amount	$ 18,991	19,170
Long-term debt	$ 18,967	19,127
Mortgage notes payable, net | Frisco, TX Non-recourse | Frisco, TX | LIBOR
Debt Instrument [Line Items]
Interest rate (percentage)	3.04%
Mortgage notes payable, net | Milford, OH Non-recourse | Milford, OH
Debt Instrument [Line Items]
Principal Amount	$ 18,760	18,760
Long-term debt	$ 18,390	18,357
Mortgage notes payable, net | Milford, OH Non-recourse | Milford, OH | LIBOR
Debt Instrument [Line Items]
Interest rate (percentage)	2.68%
Mortgage notes payable, net | Rochester, NY Non-recourse, February 2025 | Rochester, NY
Debt Instrument [Line Items]
Lease obligation interest rate	4.25%
Principal Amount	$ 19,907	20,228
Long-term debt	19,818	20,131
Mortgage notes payable, net | Rochester, NY Non-recourse, August 2027 | Rochester, NY
Debt Instrument [Line Items]
Principal Amount	101,224	101,224
Long-term debt	$ 100,324	100,267
Mortgage notes payable, net | Rochester, NY Non-recourse, August 2027 | Rochester, NY | LIBOR
Debt Instrument [Line Items]
Interest rate (percentage)	2.34%
Mortgage notes payable, net | Rochester, NY Non-recourse, August 2021 | Rochester Portfolio | LIBOR
Debt Instrument [Line Items]
Interest rate (percentage)	2.90%
Mortgage notes payable, net | One-Month LIBOR
Debt Instrument [Line Items]
Principal Amount	$ 172,200
Other notes payable | Non-Recourse
Debt Instrument [Line Items]
Principal Amount	3,914	3,693
Long-term debt	$ 3,914	3,693
Other notes payable | Non-Recourse | Oak Cottage
Debt Instrument [Line Items]
Lease obligation interest rate	6.00%
Principal Amount	$ 3,914	3,693
Long-term debt	3,914	3,693
Other notes payable | Rochester, NY Non-recourse, August 2021 | Rochester Portfolio
Debt Instrument [Line Items]
Principal Amount	12,800	12,800
Long-term debt	$ 12,403	$ 12,232