Other Real Estate Investments - Additional Information (Detail)	1 Months Ended				3 Months Ended		6 Months Ended
	May 31, 2017 USD ($)	Sep. 30, 2016 USD ($) bed	Jul. 31, 2016 USD ($) bed	Dec. 31, 2014 USD ($) a bed	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)
Real Estate Properties [Line Items]
Preferred equity investment					$ 5,200,000		$ 5,200,000
Proceeds from sale of real estate investment							7,500,000	$ 0
Receipt of preferred return							0	0
Gain on disposition of other real estate investment					3,538,000	$ 0	3,538,000	0
Interest income distribution from other real estate investment							1,500,000	0
Preferred Equity Investment [Member]
Real Estate Properties [Line Items]
Interest income					1,100,000	300,000	1,300,000	500,000
Interest income distribution from other real estate investment					975,000	$ 0	$ 975,000	$ 0
Signature Senior Living [Member]
Real Estate Properties [Line Items]
Preferred equity investment				$ 7,500,000
Return from preferred equity investment (percent)				12.00%
Number of beds planned for construction | bed				134
Area under construction | a				5
Initial lease yield (percent)				8.00%
Proceeds from sale of real estate investment	$ 7,500,000
Receipt of preferred return	2,500,000
Gain on disposition of other real estate investment	$ 3,500,000				(3,500,000)
Interest income					1,000,000
Interest income distribution from other real estate investment					$ 500,000
Cascadia Development, LLC [Member]
Real Estate Properties [Line Items]
Preferred equity investment		$ 2,300,000	$ 2,200,000
Number of beds planned for construction | bed		99	99
Initial lease yield (percent)		9.00%	9.00%
Preferred equity investment minimum yield		12.00%	12.00%
Cascadia Development, LLC [Member] | Prime Rate [Member]
Real Estate Properties [Line Items]
Basis spread of preferred equity investment yield		9.50%	9.50%