Schedule of Other Changes in Plan Assets and Benefit Obligation Recognized (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Pension Plans, Defined Benefit
Schedule Of Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets And Amounts Recognized In Balance Sheet And In Other Comprehensive Income Loss [Line Items]
Net loss (gain)	$ 8,621	$ (2,196)
Settlement loss	0	0
Amortization of prior service cost	(50)	(50)
Amortization of net (loss) gain	(988)	(1,103)
Total recognized in other comprehensive income (loss)	7,583	(3,349)
Net of tax	7,583	(2,177)
Other Pension Plans, Defined Benefit
Schedule Of Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets And Amounts Recognized In Balance Sheet And In Other Comprehensive Income Loss [Line Items]
Net loss (gain)	(932)	(5,793)
Settlement loss	0	0
Amortization of prior service cost	2,032	2,032
Amortization of net (loss) gain	1,299	395
Other		197
Total recognized in other comprehensive income (loss)	2,399	(3,169)
Net of tax	$ 1,559	$ (2,060)

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The total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation.

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Amount included in accumulated other comprehensive income (AOCI) related to prior service cost (credit) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position.

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Amount of other defined benefit plan costs.

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Amount before tax, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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Amount before tax of (increase) decrease in the value of the projected benefit obligation related to a change in an actuarial assumption and increase (decrease) in the value of the plan assets resulting from experience different from that assumed, that has not been recognized in net periodic benefit (cost) credit.

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Amount before tax of reclassification adjustment from accumulated other comprehensive income (loss) for net transition asset (obligation) related to pension and other postretirement benefit plans.

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