Geographical Concentrations that Individually Accounted for 10% or More of Total Revenues (Detail)		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Total Revenue | Geographical | State of Texas
Concentration Risk [Line Items]
Concentration risk, percentage	[1]	18.40%	16.50%	22.10%

[1] Includes rental income from operating leases, resident fees and services, and tenant reimbursement income. Adverse economic developments in this geographical area could significantly impact the Company’s results of operations and cash flow from operations, which in turn would impact its ability to pay debt service and make distributions to stockholders.