Commitments and Contingencies - Additional Information (Detail) (USD $)			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 2013 marketing commitments	Mar. 31, 2013 2012 marketing commitments	Mar. 31, 2013 Maximum	Mar. 31, 2013 Minimum
Commitment And Contingencies [Line Items]
Insurance reserves	$ 6,400,000	$ 6,600,000
Insurance reserves classified as current accrued liabilities and other	843,000	871,000
Estimate of the amount of probable loss					4,800,000	12,500,000
Marketing commitments to be spent			$ 1,200,000	$ 821,000
Marketing commitments spending period			2 years	2 years 6 months