Annual report pursuant to Section 13 and 15(d)

Related-Party Transactions - Additional Information (Detail)

v3.8.0.1
Related-Party Transactions - Additional Information (Detail) - USD ($)
 1 Months Ended 6 Months Ended 12 Months Ended
Jul. 01, 2015
Jul. 31, 2015
Dec. 31, 2015
Jun. 30, 2015
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Related Party Transaction [Line Items]              
Number of executive officers         2    
Due to adviser and administrator [1]         $ 2,289,000 $ 2,075,000  
Annual base management fee, in percentage of stockholders' equity, adjusted to unrealized gains or losses (as percent) 1.50%            
Quarterly base management fee, in percentage of stockholders' equity, adjusted to unrealized gains or losses (as percent) 0.375%            
Annual base management fee, in percentage of stockholders' equity, in excess of recorded value of preferred stock (as percent)       2.00%      
Base management fee [2]         $ 4,959,000 3,930,000 $ 3,474,000
Pre-incentive quarterly fee FFO in percentage of common stockholders' equity that will reward the adviser (as percent) 2.00%     1.75%      
Pre-incentive annual fee FFO in percentage of common stockholders' equity that will reward the adviser (as percent) 8.00%     7.00%      
Amount to be paid to adviser in percentage of pre-incentive fee condition one (as percent) 15.00%     100.00%      
Incentive fee description         However, in no event shall the incentive fee for a particular quarter exceed by 15.0% (the cap) the average quarterly incentive fee paid by us for the previous four quarters (excluding quarters for which no incentive fee was paid).    
Pre-incentive fee in percentage of common stockholders' equity that awards adviser hundred percent of amount of pre-incentive fee, maximum percentage       2.1875%      
Amount to be paid to adviser in percentage of pre-incentive fee condition two (as percent)         20.00%    
Pre-incentive fee in percentage of common stockholders' equity that awards the adviser 20% of the amount of the pre-incentive fee, minimum percentage         2.1875%    
Incentive fee [2]         $ 2,422,000 2,381,000 4,650,000
Credits related to unconditional and irrevocable voluntary waivers issued by the adviser [2]           0 2,500,000
Related-party transactions incentive fee, net         2,400,000 2,400,000 2,200,000
Capital gains-based incentive fee percentage (as percent) 15.00%            
Capital gain fee         0 0 0
Notice period for termination of agreement without cause along with the two-thirds vote   120 days          
Notice period for termination of agreement with cause   30 days          
Multiple to compute the termination fee payable (as percent)   200.00%          
Administration fee [2]         1,272,000 1,474,000 1,419,000
Fees paid         $ 200,000 $ 300,000 $ 200,000
Financing fee on total secured mortgages (as percent)         0.24% 0.32% 0.29%
Minimum              
Related Party Transaction [Line Items]              
Percentage of the amount of the mortgage (as percent)         0.15%    
Maximum              
Related Party Transaction [Line Items]              
Percentage of the amount of the mortgage (as percent)         1.00%    
Amended Advisory Agreement              
Related Party Transaction [Line Items]              
Credits related to unconditional and irrevocable voluntary waivers issued by the adviser     $ 0   $ 0 $ 0  
Adviser and Administrator              
Related Party Transaction [Line Items]              
Credits related to unconditional and irrevocable voluntary waivers issued by the adviser [2]         $ 0    
Dealer Manager              
Related Party Transaction [Line Items]              
Agreement termination date         Mar. 28, 2015    
Write-off of deferred offering costs         $ 100,000    
Dealer manager fee in percentage of gross proceeds of shares of senior common stock sold (as percent)         7.00%    
Sales commission fee in percentage of gross proceeds of shares of senior common stock sold (as percent)         3.00%    
Payments made to the dealer manager pursuant to dealer manager agreement             $ 300,000
[1] Refer to Note 2 “Related-Party Transactions”
[2] Refer to Note 2 “Related-Party Transactions”