Debt - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended
	Jun. 22, 2012	Mar. 31, 2013	Mar. 31, 2013 Domestic Rate Loans	Mar. 31, 2013 Domestic Rate Loans Federal Funds Base Rate	Mar. 31, 2013 Domestic Rate Loans Libor Rate	Mar. 31, 2013 Eurodollar Rates	Feb. 15, 2013 Term Loan	Jun. 22, 2012 Term Loan	Feb. 15, 2013 Revolving Credit Facility	Jun. 22, 2012 Revolving Credit Facility
Debt Disclosure [Line Items]
Maximum borrowing under PNC Facility	$ 27,000,000						$ 40,000,000	$ 4,000,000	$ 36,000,000	$ 23,000,000
Proceeds from borrowings under PNC facility	9,548,000
Fees and expenses relating to PNC facility	245,000
Borrowings outstanding under PNC facility		20,953,000					4,000,000
Available borrowing under PNC Facility		$ 16,313,000
PNC Facility effective Rate of interest		2.50%
Interest rate Description under PNC Facility		Interest charges with respect to loans are computed on the actual principal amount of loans outstanding during the month at a rate per annum equal to (A) with respect to domestic rate loans, the sum of (i) a rate per annum equal to the higher of (1) the base commercial lending rate of PNC, (2) the federal funds open rate plus .5% and (3) the daily LIBOR plus 1%, plus (ii) .5% and (B) with respect to Eurodollar rate loans, the sum of the Eurodollar rate plus 2.25%.
PNC facility Spread Rate for calculation of Interest			0.50%	0.50%	1.00%	2.25%