Real Estate Investments - Property Sales (Details)	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) item property	Jun. 30, 2018 facility	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) item property	Dec. 31, 2019 USD ($) item property	Dec. 31, 2018 USD ($) property item
Disposals and other
Carrying value				$ 1,102,358,000	$ 1,136,816,000
Net Gain				44,117,000	2,106,000	$ 70,682,000
Net Gain				129,000	500,000
Impairment charges				$ 3,977,000	$ 0	$ 0
Properties sold
Disposals and other
Number of properties sold | property				21	4	10
Number of beds or units in property sold | item				2,411	618	774
Sales price				$ 74,800,000	$ 15,311,000	$ 95,825,000
Carrying value				29,084,000	12,825,000	22,393,000
Net Gain				44,117,000	2,106,000	$ 70,682,000
Holdback repayment				90,000
Reassessment adjustment				$ 39,000
Properties sold | SNF
Disposals and other
Holdback amount					1,091,000
Realizable holdback amount					$ 613,000
Properties sold | SNF | Arizona
Disposals and other
Number of properties sold | property				1
Number of beds or units in property sold | item				194
Sales price				$ 12,550,000
Carrying value				2,229,000
Net Gain				$ 10,293,000
Properties sold | SNF | Colorado
Disposals and other
Number of properties sold | property				3
Number of beds or units in property sold | item				275
Sales price				$ 15,000,000
Carrying value				4,271,000
Net Gain				$ 10,364,000
Properties sold | SNF | Kansas
Disposals and other
Number of properties sold | property				3
Number of beds or units in property sold | item				250
Sales price				$ 9,750,000
Carrying value				7,438,000
Net Gain				$ 1,993,000
Properties sold | SNF | Iowa
Disposals and other
Number of properties sold | property				7
Number of beds or units in property sold | item				544
Sales price				$ 14,500,000
Carrying value				4,886,000
Net Gain				9,051,000
Holdback amount	$ 838,000		$ 838,000	150,000
Realizable holdback amount	$ 471,000			$ 229,000
Properties sold | SNF | Texas
Disposals and other
Number of properties sold | property				7
Number of beds or units in property sold | item				1,148
Sales price				$ 23,000,000
Carrying value				10,260,000
Net Gain				$ 12,287,000
Properties sold | SNF | Arizona, Georgia and Texas
Disposals and other
Number of properties sold | property					3
Number of beds or units in property sold | item					478
Sales price					$ 15,310,000
Carrying value					8,995,000
Net Gain					5,556,000
Properties sold | SNF | Georgia
Disposals and other
Carrying value					1,639,000
Proceeds from sale of properties					$ 7,920,000
Properties sold | SNF | Alabama
Disposals and other
Number of properties sold | property						4
Number of beds or units in property sold | item						454
Sales price						$ 27,975,000
Carrying value						5,695,000
Net Gain						21,987,000
Properties sold | ALF
Disposals and other
Number of facilities sold | facility		6
Properties sold | ALF | Kansas
Disposals and other
Sales price						350,000
Carrying value						$ 346,000
Properties sold | ALF | Texas
Disposals and other
Number of properties sold | property					1
Number of beds or units in property sold | item					140
Sales price					$ 1,000
Carrying value					3,830,000
Net Gain					(3,950,000)
Properties sold | ALF | Ohio and Pennsylvania
Disposals and other
Number of properties sold | property						6
Number of beds or units in property sold | item						320
Sales price						$ 67,500,000
Carrying value						16,352,000
Net Gain						$ 48,695,000
Preferred Care, Inc.
Disposals and other
Number of properties sold | property	21
Number of beds or units in property sold | item	2,411
Net Gain	$ 44,073,000		$ 44,000,000
Preferred Care, Inc. | Properties sold | Texas
Disposals and other
Carrying value					871,000
Proceeds from sale of properties					140,000
Preferred Care, Inc. | Properties sold | SNF | Arizona
Disposals and other
Carrying value					6,485,000
Proceeds from sale of properties					$ 7,250,000