XML 80 R68.htm IDEA: XBRL DOCUMENT v3.10.0.1
Shared-Based Compensation - Additional Information (Detail)
$ / shares in Units, $ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
$ / shares
shares
Jun. 30, 2018
USD ($)
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of options granted 55,300 55,300
Weighted average grant date fair value of the options granted | $ / shares   $ 10.68
Total grant-date fair value of restricted stock | $   $ 1.8
Restricted Stock [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock units issued   86,516
Fair value assumptions, exercise price | $ / shares $ 24.55 $ 24.55
TSR Awards [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock units issued   55,000
Percentage of shares issuable based on threshold performance   50.00%
Percentage of shares issuable based on target performance   100.00%
Percentage of shares issuable based on maximum performance   150.00%
ROIC Awards [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock units issued   55,000
Percentage of shares issuable based on threshold performance   35.00%
Percentage of shares issuable based on target performance   100.00%
Percentage of shares issuable based on maximum performance   150.00%
Officers and Key Employees [Member] | Restricted Stock [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock awards granted vesting period   3 years
Non-executive Directors [Member] | Restricted Stock [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock awards granted vesting period   1 year