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Common Stock - Additional Information (Detail)
Mar. 31, 2017
USD ($)
$ / shares
shares
Feb. 10, 2017
USD ($)
Feb. 01, 2017
USD ($)
$ / shares
shares
Nov. 29, 2016
USD ($)
$ / shares
shares
Nov. 09, 2016
USD ($)
$ / shares
shares
Dec. 31, 2016
shares
Class Of Stock [Line Items]            
Common stock split ratio         2,200  
Sale of shares of common stock     1,500,000      
Purchase price per share | $ / shares $ 17.50   $ 17.50      
Common stock, shares authorized 350,000,000       350,000,000 350,000,000
Preferred stock, undesignated shares authorized         10,000,000  
Proceeds from issuance of common stock net of underwriting discounts and expenses | $     $ 24,200,000      
Stock sold by selling shareholders 4,450,000          
Proceeds from issuance of common stock | $ $ 0 $ 0        
Underwriters option period 30 days          
Maximum            
Class Of Stock [Line Items]            
Additional common stock shares granted by selling shareholders to underwriters option 893          
Initial Public Offering            
Class Of Stock [Line Items]            
Sale of shares of common stock         11,700,000  
Purchase price per share | $ / shares         $ 11.00  
Net proceed received from IPO after deducting underwriting discounts and commissions | $         $ 121,000,000  
Over-Allotment Option            
Class Of Stock [Line Items]            
Purchase price per share | $ / shares       $ 11.00    
Additional common stock, shares issued to underwriters       878,000    
Net proceed received from underwriter option exercise after deducting underwriting discounts and commissions | $       $ 9,700,000