Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.8.0.1
Summary of Significant Accounting Policies - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2017
Segment
Summary of Significant Accounting Policies [Line Items]  
Financing receivable, past due 90 days
Cash and cash equivalents original maturity period 3 months
Real estate investment description To qualify as a REIT, we must meet on an ongoing basis a number of organizational and operational requirements, including a requirement that we currently distribute at least 90% of our net taxable income, excluding capital gains, to our stockholders.
Number of segment reported 1
2013 Plan [Member] | Performance Based Restricted Stock Award [Member]  
Summary of Significant Accounting Policies [Line Items]  
Stock-based award vesting minimum percentage 0.00%
Stock-based award vesting maximum percentage 200.00%
Stock-based award, range of vesting percentage description Certain awards earned under the plan are based on achieving various performance targets, which are generally earned between 0% and 200% of the initial target, depending on the extent to which the performance target is met.
Minimum [Member]  
Summary of Significant Accounting Policies [Line Items]  
Percentage of taxable income distributed to stockholders 90.00%