Income Taxes - Earnings Before Income Taxes and Related Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Domestic	$ 53,963	$ 44,774	$ 37,955
Foreign	3,399	4,942	2,545
Earnings Before Income Taxes	57,362	49,716	40,500
Federal-
Current	18,311	15,077	13,336
Temporary differences
Fixed asset basis differences and depreciation	121	2	(155)
Intangible asset basis differences and amortization	(339)	(354)	(312)
Currently non-deductible expenses and reserves	(425)	(397)	(627)
Stock-based compensation	(282)	(599)	(706)
Tax credit carryforwards	(717)
Other, net	43	74	35
Subtotal	16,712	13,803	11,571
State and local	2,013	1,521	1,213
Foreign	605	1,021	885
Income Tax Provision	$ 19,330	$ 16,345	$ 13,669

The component of income tax expense for the period representing amounts paid or payable (or refundable) as determined by applying the provisions of enacted federal tax law to the domestic taxable Income or Loss from continuing operations.

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The change during the period in the entity's deferred tax assets and liabilities attributable to continuing operations as determined by applying enacted tax laws other than federal, domestic, foreign, state or local. Items affecting deferred income taxes and required to be disclosed, but not included elsewhere, would also be designated as "Other"; for example, adjustments of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity and adjustments to be beginning-of-year balance of a valuation allowance because of a change in circumstance that causes a change in judgment about the realizability of the related deferred tax asset in future periods.

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The tax effect as of the balance sheet date of the amount of future tax deductions arising from all unused tax credit carryforwards which have been reduced by a valuation allowance.

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The sum of domestic current and deferred income tax expense or benefit attributable to continuing operations.

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The sum of foreign current income tax expense or benefit and foreign deferred income tax expense or benefit pertaining to Income or Loss from continuing foreign operations.

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The sum of state and local current and deferred income tax expense or benefit attributable to continuing operations.

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