Income Taxes - Summary of Reconciliation Income Tax Provision from the Statutory Federal Income Tax Rate (Detail) (USD $)	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Tax Disclosure [Abstract]
Income taxes at federal statutory rate (35%)	$ 15,947,000	$ 20,633,000	$ 15,363,000
State income taxes, net of federal benefit	1,535,000	1,826,000	1,172,000
Uncertain tax positions	1,346,000	(245,000)	26,000
Adjustments to returns as filed	(1,978,000)	(293,000)	821,000
Other	124,000	194,000	(217,000)
Total	$ 16,974,000us-gaap_IncomeTaxExpenseBenefit	$ 22,115,000us-gaap_IncomeTaxExpenseBenefit	$ 17,165,000us-gaap_IncomeTaxExpenseBenefit

Income Tax Reconciliation Uncertain Tax Positions

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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