Real Estate Investments - Operator changes (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($) item property	Jun. 30, 2017 USD ($) item property	Dec. 31, 2016 USD ($)
Other disclosures
Write-off		$ 1,880	$ 1,880
Straight-line rent receivable		$ 59,287	$ 59,287	$ 55,276
ALF | 2017 Acquisitions
Other disclosures
Number of beds/units acquired | item			240
Purchase Price			$ 54,463
ALF | Operator agreements in transition
Other disclosures
Number of properties in transition | property		2
Annual rent on lease under default or terminated agreement		$ 2,401
Annual rent under new agreement, before property additions		3,829
Annual rent under new agreement, after property additions		$ 6,272
ALF | Operator agreements in transition | Forecast | Minimum
Other disclosures
Write-off	$ 0
ALF | Operator agreements in transition | Forecast | Maximum
Other disclosures
Write-off	$ 383
MC | Operator agreements in transition
Other disclosures
Number of properties in transition | property		2
Write-off		$ 1,880
MC | Master lease in default
Other disclosures
Annual rent on lease under default or terminated agreement		$ 11,721
Number of properties | property		11	11
Number of development commitments | property		2
Net book value		$ 111,582	$ 111,582
Straight-line rent receivable		8,608	8,608
Other assets		$ 6,577	$ 6,577
Memory Care Property with 60 Units | MC | 2017 Acquisitions
Other disclosures
Number of beds/units acquired | item		60	60
Purchase Price		$ 15,650	$ 15,650
Properties acquired or in transition
Other disclosures
Number of properties | property		3	3