Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Business Acquisition [Line Items]
Reduction in liability for contingent consideration		$ 400,000
NEP [Member]
Business Acquisition [Line Items]
Total consideration of other acquisitions		12,100,000
Contingent consideration maximum amount earned		3,180,000
Contingent consideration	2,500,000	2,500,000
Consideration paid as common stock		153,153
NEP [Member] | Current Liabilities [Member]
Business Acquisition [Line Items]
Contingent consideration net	$ 2,200,000	$ 1,800,000