Other Real Estate Investments - Additional Information (Detail) $ in Thousands	1 Months Ended			12 Months Ended
	Sep. 30, 2016 USD ($) bed	Jul. 31, 2016 USD ($) bed	Dec. 31, 2014 USD ($) a bed	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Real Estate Properties [Line Items]
Preferred equity investment				$ 13,900
Recognized interest income				$ 700	$ 900	$ 32
Signature Senior Living [Member]
Real Estate Properties [Line Items]
Preferred equity investment			$ 7,500			$ 7,500
Return from preferred equity investment			12.00%
Number of beds planned for construction | bed			134
Area under construction | a			5
Initial lease yield			8.00%
Cascadia Development, LLC [Member]
Real Estate Properties [Line Items]
Preferred equity investment	$ 2,300	$ 2,200
Number of beds planned for construction | bed	99	99
Rate of return (minimum)	12.00%	12.00%
Initial lease yield	9.00%	9.00%