Credit Agreement - Additional Information (Detail) - Credit Agreement [Member] - Unsecured Line of Credit Agreement [Member] - USD ($)		9 Months Ended
	Sep. 22, 2015	Sep. 30, 2015
Line Of Credit Facility [Line Items]
Line of credit, interest rate description		The Credit Agreement shall bear interest at either (1) a rate per annum equal to 1.5% below the bank’s applicable prime rate or (2) 1.5% above the Bank’s applicable LIBOR rate, in each case as defined in the Credit Agreement.
Line of credit, amount outstanding		$ 0
Prime Rate [Member] | Minimum [Member]
Line Of Credit Facility [Line Items]
Line of credit, interest rate, basis spread on variable rate		1.50%
LIBOR Rate [Member] | Maximum [Member]
Line Of Credit Facility [Line Items]
Line of credit, interest rate, basis spread on variable rate		1.50%
JPMorgan Chase Bank, N.A. [Member]
Line Of Credit Facility [Line Items]
Line of credit, term	2 years
Line of credit, maximum borrowing capacity	$ 12,000,000