Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation Plans - Summary of Restricted Common Stock Activity - Pre-IPO (Detail)

v3.3.1.900
Stock-Based Compensation Plans - Summary of Restricted Common Stock Activity - Pre-IPO (Detail) - $ / shares
 1 Months Ended 10 Months Ended 12 Months Ended
Nov. 30, 2015
Aug. 31, 2015
May. 31, 2015
Feb. 28, 2015
Dec. 31, 2014
Nov. 30, 2014
Aug. 31, 2014
May. 31, 2014
Feb. 28, 2014
Oct. 31, 2013
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Nonvested shares, beginning balance                     1,207,009 913,915    
Issued 9,922 30,755 22,464 25,567 216,411 14,222 18,820 61,655 38,088   88,708 349,196    
Nonvested shares, ending balance         1,207,009           1,026,113 1,207,009 913,915  
Nonvested weighted average grant date fair value per share, beginning balance                     $ 18.23 $ 14.46    
Nonvested weighted average grant date fair value per share, ending balance         $ 18.23           $ 21.17 18.23 $ 14.46  
MMREIS Common Stock [Member]                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Exchange of common stock                   (234,489)       (234,489)
MMREIS Common Stock [Member] | MMREIS Managing Directors [Member]                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Exchange of common stock                   (28,749)        
Restricted Common Stock [Member] | Pre-IPO [Member]                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Nonvested shares, beginning balance                   27,999     27,999  
Issued                         750  
Nonvested shares, ending balance                           27,999
Restricted common stock vested ending balance, Shares                         0  
Restricted common stock unvested ending balance, Shares                         0  
Nonvested weighted average grant date fair value per share, beginning balance                   $ 23.67   $ 0 $ 23.67  
Issued/Granted, Weighted-Average Grant Date Fair Value                         28.86  
Exchange of common stock, Weighted-Average Grant Date Fair Value                         0  
Nonvested weighted average grant date fair value per share, ending balance                         $ 0 $ 23.67
Restricted Common Stock [Member] | Pre-IPO [Member] | MMREIS Common Stock [Member] | MMREIS Managing Directors [Member]                            
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                            
Exchange of common stock                         (28,749)