Goodwill and Other Intangible Assets - Narrative (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Goodwill and Other Intangible Assets [Line Items]
Goodwill impairment	$ 646,000	$ 81,877,000	$ 646,000	$ 81,877,000
Bargain purchase gain on acquisition	662,000	0	662,000	0
Additions to goodwill			0
Amortization expense of intangible assets	$ 2,000,000	$ 2,200,000	$ 6,500,000	$ 6,700,000
Customer relationships
Goodwill and Other Intangible Assets [Line Items]
Amortization period of intangible assets			15 years
Non-compete agreements
Goodwill and Other Intangible Assets [Line Items]
Amortization period of intangible assets			5 years
Other intangible assets
Goodwill and Other Intangible Assets [Line Items]
Amortization period of intangible assets			15 years