Annual report pursuant to Section 13 and 15(d)

Stock Compensation Plans - Stock Option Awards (Detail)

v3.8.0.1
Stock Compensation Plans - Stock Option Awards (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
12 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Outstanding, Shares Under Option, Beginning Balance 69 83 90
Exercised, Shares Under Option   (13) (7)
Cancelled, Shares Under Option   (1)  
Outstanding, Shares Under Option, Ending Balance 69 69 83
Vested or expected to vest, Shares Under Option 69    
Exercisable, Shares Under Option 69    
Outstanding, Weighted Average Exercise Price, Beginning Balance $ 20.26 $ 19.03 $ 18.57
Exercised, Weighted Average Exercise Price   11.45 13.30
Cancelled, Weighted Average Exercise Price   30.88  
Outstanding, Weighted Average Exercise Price, Ending Balance 20.26 $ 20.26 $ 19.03
Vested or expected to vest, Weighted Average Exercise Price 20.26    
Exercisable, Weighted Average Exercise Price $ 20.26    
Outstanding, Weighted Average Remaining Contractual Term, Ending Balance 2 years 10 months 2 days    
Vested or expected to vest, Weighted Average Remaining Contractual Term 2 years 10 months 2 days    
Exercisable, Weighted Average Remaining Contractual Term 2 years 10 months 2 days    
Outstanding, Aggregate Intrinsic Value, Ending Balance $ 209    
Vested or expected to vest, Aggregate Intrinsic Value 209    
Exercisable, Aggregate Intrinsic Value $ 209