Annual report pursuant to Section 13 and 15(d)

Employee Benefit Plans - Fair Values of Company's Pension Plan Assets by Asset Category (Detail)

v3.6.0.2
Employee Benefit Plans - Fair Values of Company's Pension Plan Assets by Asset Category (Detail) - Pension Plans, Defined Benefit [Member] - USD ($)
$ in Thousands
Mar. 31, 2016
Mar. 31, 2015
Mar. 31, 2014
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 36,471 $ 40,384 $ 38,548
Cash [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 103 126  
U.S. companies, Equity Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 20,010 21,586  
International companies, Equity Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4,459 4,854  
Fixed income, Corporate bond funds, Intermediate-term [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 9,520 11,109  
Fixed income, Corporate bond funds, Short-term [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 2,379 2,709  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 36,471 40,384  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 103 126  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. companies, Equity Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 20,010 21,586  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | International companies, Equity Securities [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 4,459 4,854  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed income, Corporate bond funds, Intermediate-term [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets 9,520 11,109  
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fixed income, Corporate bond funds, Short-term [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Fair value of plan assets $ 2,379 $ 2,709