Goodwill and Intangible Assets - Summary of Intangible Assets of Company by Major Class (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	$ 104,744	$ 92,060
Intangible assets subject to amortization, Accumulated Amortization	(44,545)	(38,858)
Intangible assets subject to amortization, Net Carrying Amount	60,199	53,202
Intangible Assets, Gross Carrying Amount	117,044	104,360
Intangible Assets, Net Carrying Amount	72,499	65,502
Customer relationships and other intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	89,632	84,470
Intangible assets subject to amortization, Accumulated Amortization	(41,145)	(36,232)
Intangible assets subject to amortization, Net Carrying Amount	48,487	48,238
Intangible assets subject to amortization, Weighted Average Useful Life (years)	17 years	17 years
Non-compete agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	4,679	4,700
Intangible assets subject to amortization, Accumulated Amortization	(2,108)	(1,952)
Intangible assets subject to amortization, Net Carrying Amount	2,571	2,748
Intangible assets subject to amortization, Weighted Average Useful Life (years)	4 years	4 years
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization, Gross Carrying Amount	10,433	2,890
Intangible assets subject to amortization, Accumulated Amortization	(1,292)	(674)
Intangible assets subject to amortization, Net Carrying Amount	9,141	2,216
Intangible assets subject to amortization, Weighted Average Useful Life (years)	14 years	5 years
Trademarks not subject to amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets not subject to amortization, Gross Carrying Amount	$ 12,300	$ 12,300