Schedule of Fair Values of Defined Benefit Plans (Detail) - USD ($) $ in Thousands |
Mar. 31, 2018 |
Mar. 31, 2017 |
Mar. 31, 2016 |
---|---|---|---|
Defined Benefit Plan Disclosure [Line Items] | |||
Fair values of defined benefit plans | $ 33,412 | $ 26,410 | $ 21,424 |
Equity Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair values of defined benefit plans | 16,533 | 18,375 | |
Fixed Income Securities [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair values of defined benefit plans | 15,799 | 7,166 | |
Real Estate Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair values of defined benefit plans | 163 | 147 | |
Cash Equivalents [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair values of defined benefit plans | 704 | 258 | |
Commodity Linked Funds [Member] | |||
Defined Benefit Plan Disclosure [Line Items] | |||
Fair values of defined benefit plans | $ 213 | $ 464 |