Goodwill and Intangible Assets - Additional Information (Detail) (USD $)			3 Months Ended		9 Months Ended		0 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Customer Relationships	Sep. 30, 2013 Customer Relationships	Sep. 30, 2014 Customer Relationships	Sep. 30, 2013 Customer Relationships	Oct. 31, 2010 Non-compete Agreement	Sep. 30, 2013 Non-compete Agreement	Sep. 30, 2013 Non-compete Agreement
Goodwill And Intangible Assets Disclosure [Line Items]
Accumulated impairment losses	$ 0	$ 0
Amortization period (in years)					7 years				3 years
Amortization expense			$ 911,000	$ 911,000	$ 2,700,000	$ 2,700,000		$ 117,000	$ 350,000
Contract term							3 years