Goodwill and Intangible Assets - Summary of Acquisition-Related Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,471	$ 1,471
Accumulated Amortization	(574)	(402)
Total / Net Carrying Value	897	1,069
Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,275	1,275
Accumulated Amortization	(378)	(276)
Total / Net Carrying Value	897	999
Non-compete agreements [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	196	196
Accumulated Amortization	(196)	(126)
Total / Net Carrying Value	$ 0	$ 70