Annual report pursuant to Section 13 and 15(d)

Share-based Compensation - Additional Information (Detail)

v3.10.0.1
Share-based Compensation - Additional Information (Detail)
12 Months Ended
Dec. 31, 2018
plan
$ / shares
shares
Dec. 31, 2017
shares
Dec. 31, 2016
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of incentive plans | plan 2    
Options granted in period (shares)   0 0
2013 Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares of common stock to be granted under equity incentive awards 1,500,000    
Shares available for issuance under the Plan 440,055    
2007 and 2013 Plan      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Options granted in period (shares) 0    
Stock options, expiration term from date of grant 10 years    
Closing price of common stock | $ / shares $ 19.70    
2007 and 2013 Plan | Minimum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Period of continuous service 3 years    
2007 and 2013 Plan | Maximum      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Period of continuous service 5 years