Acquisitions - Additional Information (Detail)	1 Months Ended						12 Months Ended
	Nov. 30, 2015 USD ($)	Oct. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Aug. 31, 2015 USD ($)	Aug. 31, 2014 USD ($)	Jan. 31, 2013 USD ($)	Dec. 31, 2016 USD ($) Property	Dec. 31, 2015 USD ($) Property	Dec. 31, 2014 USD ($)
Business Acquisition [Line Items]
Number of properties acquired | Property								39
Revenues attributable to properties							$ 600,000	$ 18,000,000
Net loss attributable to properties							$ 400,000	$ 8,800,000
Number of real estate acquired for development | Property							0
Co-venture partner's interest in the acquired business							5.00%
Payment to acquire interest in joint ventures									$ 1,584,000
Gain from change of control in equity method investment									2,798,000
Senior Housing
Business Acquisition [Line Items]
Number of properties acquired | Property								15
Medical Office
Business Acquisition [Line Items]
Number of properties acquired | Property								22
Post-acute Care Hospital
Business Acquisition [Line Items]
Number of properties acquired | Property								1
Acute Care Hospital
Business Acquisition [Line Items]
Number of properties acquired | Property								1
Waterstone on Augusta (Greenville, SC)
Business Acquisition [Line Items]
Purchase price of land				$ 2,300,000
Maximum development budget				$ 27,000,000
Location				Greenville, South Carolina
Date Acquired				Aug. 31, 2015
Welbrook Senior Living Grand Junction (Grand Junction, CO)
Business Acquisition [Line Items]
Purchase price of land			$ 1,100,000
Maximum development budget			$ 13,100,000
Location			Grand Junction, Colorado
Date Acquired			Sep. 30, 2015
Wellmore of Lexington (Lexington, SC)
Business Acquisition [Line Items]
Purchase price of land			$ 2,300,000
Maximum development budget			$ 53,900,000
Location			Lexington, South Carolina
Date Acquired			Sep. 30, 2015
Fieldstone at Pear Orchard (Yakima, Washington)
Business Acquisition [Line Items]
Purchase price of land		$ 1,000,000
Maximum development budget		$ 15,300,000
Location		Yakima, Washington
Date Acquired		Oct. 31, 2015
Percentage of membership interest acquired		75.00%
Co-venture partner's interest in the acquired business		25.00%
The Dogwood Forest of Grayson (Grayson, GA)
Business Acquisition [Line Items]
Purchase price of land	$ 1,800,000
Maximum development budget	$ 26,000,000
Location	Grayson, Georgia
Date Acquired	Nov. 30, 2015
Montecito Joint Venture
Business Acquisition [Line Items]
Date Acquired					Aug. 31, 2014	Jan. 31, 2013
Percentage of membership interest acquired					10.00%	90.00%
Co-venture partner's interest in the acquired business						10.00%
Value of equity issued in acquisition						$ 7,000,000
Payment to acquire interest in joint ventures					$ 1,600,000				1,584,000
Percentage of membership interest acquired							100.00%
Fair value of equity interest in Montecito Joint Venture immediately before the acquisition date					5,700,000
Gain from change of control in equity method investment					$ 2,800,000				$ 2,798,000