Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended							1 Months Ended
	Dec. 31, 2012 Y	Dec. 31, 2012 Prime and Federal Fund Rate [Member]	Dec. 31, 2012 Prime and Federal Fund Rate [Member] Minimum [Member]	Dec. 31, 2012 Prime and Federal Fund Rate [Member] Maximum [Member]	Dec. 31, 2012 London Interbank Offered Rate (LIBOR) [Member]	Dec. 31, 2012 London Interbank Offered Rate (LIBOR) [Member] Minimum [Member]	Dec. 31, 2012 London Interbank Offered Rate (LIBOR) [Member] Maximum [Member]	Oct. 10, 2012 Revolving Credit Agreement [Member] Y	Aug. 14, 2008 Revolving Credit Agreement [Member] Y	Dec. 31, 2012 Letter Of Credit [Member]
Loss Contingencies [Line Items]
Operating lease term range, minimum years	1
Operating lease term range, maximum years	9
Contingent liability of Zebra										$ 482,000
Revolving credit agreement in years								5	5
Revolving credit agreement								250,000,000	100,000,000
Spread on federal funds effective rate		0.50%
Spread in effect at closing for LIBOR-based loans		0.00%			1.00%
Ratio to total debt to EBITDA		Ranges from 0.25% to 1.75%			Ranges from 1.00% to 1.75%
Percentage of total debt to EBITDA			0.25%	1.75%		1.00%	1.75%
Revolving credit agreement amount										$ 2,300,000