Schedule of Reconciliation of Obligations and Fair Values of Plan Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Compensation And Retirement Disclosure [Abstract]
Benefit Obligation at April 1,	$ 29,892	$ 29,586
Service Cost - Benefits Earned During the Period	874us-gaap_DefinedBenefitPlanServiceCost	1,129us-gaap_DefinedBenefitPlanServiceCost	785us-gaap_DefinedBenefitPlanServiceCost
Interest Cost on Projected Benefit Obligation	1,278us-gaap_DefinedBenefitPlanInterestCost	1,222us-gaap_DefinedBenefitPlanInterestCost	1,222us-gaap_DefinedBenefitPlanInterestCost
Amendments	805
Actuarial (Gain) Loss	9,823	(1,237)
Benefits Paid	(881)us-gaap_DefinedBenefitPlanBenefitsPaid	(808)us-gaap_DefinedBenefitPlanBenefitsPaid
Benefit Obligation at March 31,	41,791	29,892	29,586
Fair Value of Plan Assets at April 1,	21,189	18,693
Actual Return on Plan Assets	937	1,735
Employer Contributions	810	1,569
Fair Value of Plans at March 31,	22,055	21,189	18,693
Unfunded Status at March 31,	(19,736)	(8,703)
Accrued Benefit Liability	(19,736)	(8,703)
Accumulated Other Comprehensive Losses - Net Actuarial Loss	18,376	8,419
Accumulated Other Comprehensive Losses - Prior Service Cost	809	15
Accumulated Other Comprehensive Losses	19,185	8,434
Tax impact	(7,118)	(2,952)
Accumulated Other Comprehensive Losses, net of tax	$ 12,067	$ 5,482

Defined benefit plan accrued benefit cost.

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Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Tax Impact

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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 pretax 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 pretax net amount of gains and losses that are not yet recognized as a component of net periodic benefit cost, and that are recognized as increases or decreases in other comprehensive income as they arise. Gains and losses are due to changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan.

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Amount related to the pretax cost of benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation, which has not yet been recognized as components of net periodic benefit cost.

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The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

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-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

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Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan.

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-Glossary Gain or Loss

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1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date.

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The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.

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The increase in the fair value of plan assets from contributions made by the employer.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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The funded status is measured as the difference between the fair value of plan assets and the benefit obligation. Will normally be the same as the net Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total.

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The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time.

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The amount of increase or decrease due to a change in the terms of an existing plan or the initiation of a new plan. A plan amendment may increase or decrease benefits, including those attributed to years of service already rendered.

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The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan.

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