XML 49 R38.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation - Summary of Activity Relating to Restricted Stock (Detail) - Restricted Stock Units [Member] - shares
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2018
Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Outstanding, Shares at beginning balance-Restricted stock   29,100  
Granted, Shares- Restricted stock   71,400 32,500
Vested, Shares-Restricted stock 0 (14,550) 0
Forfeited, Shares-Restricted stock   (900)  
Outstanding, Shares at ending balance-Restricted stock 85,050 85,050