Annual report pursuant to Section 13 and 15(d)

Stock Compensation Plans - Additional Information (Detail)

v3.6.0.2
Stock Compensation Plans - Additional Information (Detail) - USD ($)
$ in Thousands
12 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Cash proceeds from the exercise of stock options $ 97 $ 47 $ 581
Total intrinsic value of the stock options exercised 71 32 1,221
Unrecognized stock-based compensation expense $ 1,063    
Weighted average period for recognize expense 1 year 5 months 9 days    
Options, stock awards and performance awards available for future grants 377,000    
Stock Compensation Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock based compensation expense $ 653 598 582
Income tax benefit to stock based compensation 230 210 205
Increase in capital in excess of par value for the income tax benefit realized upon exercise of stock options and vesting of restricted $ 5 $ 197 $ 268
Restricted Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock awarded 34,000 30,000 32,000
Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock options maximum term 10 years    
Amended and Restated 2000 Incentive Plan [Member] | Stock Compensation Plan [Member] | Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares authorized 1,375,000    
Amended and Restated 2000 Incentive Plan [Member] | Restricted Stock [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock awarded 34,000 30,000 32,000
Amended and Restated 2000 Incentive Plan [Member] | Restricted Stock [Member] | Performance Vested Restricted Stock [Member] | Officer [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock awarded 15,000 12,000 14,000
Share-based compensation vesting percentage 100.00%    
Vesting period 3 years    
Amended and Restated 2000 Incentive Plan [Member] | Restricted Stock [Member] | Time Vested Restricted Stock [Member] | Officers and Key Employees [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock awarded 12,000 11,000 12,000
Share-based compensation vesting percentage 33.33%    
Vesting period 3 years    
Amended and Restated 2000 Incentive Plan [Member] | Restricted Stock [Member] | Time Vested Restricted Stock [Member] | Director [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Restricted stock awarded 7,000 7,000 6,000
Share-based compensation vesting percentage 100.00%    
Vesting period 1 year    
Amended and Restated 2000 Incentive Plan [Member] | Restricted Stock [Member] | Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of shares authorized 250,000    
Amended and Restated 2000 Incentive Plan [Member] | Employee Stock Option [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock option awards granted 0    
Long Term Incentive Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Related liability recorded under plan $ 0 $ 158  
Long Term Incentive Plan [Member] | Director [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Amounts paid to participant 158 157  
Employee Stock Purchase Plan [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock based compensation expense 44 55 $ 57
Income tax benefit to stock based compensation 16 19 20
Increase in capital in excess of par value for the income tax benefit realized upon exercise of stock options and vesting of restricted $ 1 $ 3 $ 3
Discounted purchase price of common stock percentage on fair market value 85.00%    
Issue of treasury stock to the ESPP for the offering periods 16,000 12,000 16,000