Debt - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 22, 2012
Debt Disclosure [Line Items]
Maximum borrowing under PNC Facility		$ 27,000,000
Proceeds from borrowings under PNC facility	9,548,000
Fees and expenses relating to PNC facility	245,000
Borrowings outstanding under PNC facility	9,127,000
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 credit Facility expiration date	Jun. 22, 2015
Domestic Rate Loans
Debt Disclosure [Line Items]
PNC facility Spread Rate for calculation of Interest	0.50%
Domestic Rate Loans | Federal Funds Base Rate
Debt Disclosure [Line Items]
PNC facility Spread Rate for calculation of Interest	0.50%
Domestic Rate Loans | Libor Rate
Debt Disclosure [Line Items]
PNC facility Spread Rate for calculation of Interest	1.00%
Eurodollar Rates
Debt Disclosure [Line Items]
PNC facility Spread Rate for calculation of Interest	2.25%
Term Loan
Debt Disclosure [Line Items]
Maximum borrowing under PNC Facility		4,000,000
Revolving Credit Facility
Debt Disclosure [Line Items]
Maximum borrowing under PNC Facility		$ 23,000,000