Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Line Items]
Income tax expense	$ 408	$ 284	$ 1,060	$ 951
Tax effects of goodwill amortized for income tax purposes	$ 295	$ 228	$ 692	$ 636

The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.