Dispositions, Assets Held for Sale and Discontinued Operations - Narrative (Details) $ in Thousands, shares in Millions			3 Months Ended					12 Months Ended
	Feb. 01, 2018 USD ($) unit Rate shares	Oct. 01, 2017 USD ($) Rate	Dec. 31, 2018 USD ($)		Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)		Dec. 31, 2017 USD ($) unit	Dec. 31, 2016 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of discontinued operations			$ 10,676		$ 0	$ 0	$ 46,184	$ 56,860		$ 0	$ 0
Realized gain on sale of special insurance properties								1,800
Cash consideration recognized from gain on sale			10,676	[1]				10,676	[1]	$ 0
Ownership interest sold | unit										2
Impairment of assets held for sale								0		$ 0
Impairment of real estate										0	0
Siena Disposition
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration		$ 2,500
Seller provided financing		$ 11,000
Seller provided financing, interest rate | Rate		10.00%
Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of senior living properties | unit	2
Pre-tax comprehensive income								54,900
Gain on sale of discontinued operations										$ 0	$ 0
Discontinued Operations | Care Disposition
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash consideration recognized from gain on sale			$ 10,700					10,700
Discontinued Operations | Invesque Inc. | Care Disposition
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 150,700
Shares received | shares	16.6
Ownership in acquiring company | Rate	34.00%
Discontinued Operations | Interest Rate Swap
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Reclassification of the interest rate swap from AOCI								$ 3,800
Maximum | Building
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated useful lives								40 years
Maximum | Building Improvements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated useful lives								9 years

[1] Related to the gain contingency on sale of Care recorded in December 2018. See Note (3) Dispositions, Assets Held for Sale and Discontinued Operations.