Acquisitions of Businesses and Other Intangibles - Additional Information (Detail) $ in Thousands	3 Months Ended		5 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	May 09, 2016 Location
Business Acquisition [Line Items]
Amortization of intangible assets	$ 1,000	$ 1,100		$ 3,800	$ 3,000
Net income	$ 1,629	$ (285)		(2,114)	$ (3,819)	$ (2,382)
TNT
Business Acquisition [Line Items]
Number of municipalities covered \| Location							120
Revenue			$ 12,800
Net income			$ 2,000
Backlog
Business Acquisition [Line Items]
Amortization of intangible assets				$ 3,300		$ 2,600