Debt - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013
Debt Instrument [Line Items]
New credit agreement entering date	Jul. 13, 2011
Secured revolving credit facility term, years	5 years
Secured revolving credit facility current borrowing capacity	$ 120,000,000
Interest rate on outstanding borrowings	Borrowings under the Credit Facility bear interest at a variable rate based upon, at the Company’s option, either LIBOR or the base rate (which is the highest of (i) the prime rate, (ii) 0.5% plus the overnight federal funds rate, and (iii) 1.0% in excess of the three-month LIBOR rate), plus in each case, an applicable margin. The applicable margin for LIBOR loans, based on the applicable leverage ratio, is either 2.25% or 2.50% per annum, and the applicable margin for base rate loans, based on the applicable leverage ratio, is either 1.25% or 1.50% per annum. At June 30, 2013 our rates, inclusive of applicable margins, was 4.5 for prime. respectively.
Credit facility basis spread on variable rate LIBOR	1.00%
Credit facility reference rate LIBOR	Three-month LIBOR
Percentage of fee payment on unused line of credit facility	0.375%
Outstanding debt	0
Credit facility financial covenants terms	(i) a maximum ratio of consolidated total debt to consolidated adjusted EBITDA of 3.001.00, and (ii) a minimum consolidated fixed charge coverage ratio of 1.251.00
Maximum acquisition expense	2,000,000
Maximum cash non-operating expense	250,000
Maximum amount of various fees, cost and expenses to be taken in adjusted EBITDA	$ 1,500,000
Period of calculating EBITDA (in month)	12 months
Minimum [Member]
Debt Instrument [Line Items]
Applicable margin leverage ratio for LIBOR loans	2.25%
Applicable margin leverage ratio for base rate loan for LIBOR loans	1.25%
Maximum [Member]
Debt Instrument [Line Items]
Applicable margin leverage ratio for LIBOR loans	2.50%
Applicable margin leverage ratio for base rate loan for LIBOR loans	1.50%
Federal Funds Rate [Member]
Debt Instrument [Line Items]
Interest rate on outstanding borrowings	0.5% plus the overnight federal funds rate
Libor Rate [Member]
Debt Instrument [Line Items]
Interest rate on outstanding borrowings	1.0% in excess of the three-month LIBOR rate
Credit facility basis spread on variable rate LIBOR	0.50%
Prime Rate [Member]
Debt Instrument [Line Items]
Variable interest rate	4.50%