XML 152 R138.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation (Restricted Stock Awards) - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Retained income dividends cumulatively paid $ 1,887    
Declared dividends charged to earnings 195    
General and Administrative Personnel Expense [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Retained income dividends cumulatively paid 1,346    
Declared dividends charged to earnings 159    
Other Operating Expense [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Retained income dividends cumulatively paid 541    
Declared dividends charged to earnings 36    
Restricted Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Recognized compensation expenses 4,111 $ 4,217 $ 4,198
Total unrecognized compensation expense, Nonvested restricted stock arrangements granted $ 11,199 $ 9,101  
Recognition of remaining compensation expense over a weighted-average period 2 years 9 months 18 days    
Awards issued during the period 189,860 154,936 142,440
Other Than Service Based Restricted Stock Awards [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Awards issued during the period 0 0 0