Intangible Assets by Major Class (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Goodwill And Intangible Assets [Line Items]
Intangible assets, Gross Carrying Amount	$ 155,431	$ 214,166
Finite lived intangible assets, Gross Carrying Amount	149,831	208,566
Intangible assets, Accumulated Amortization	78,397	117,018
Customer Relationships
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Gross Carrying Amount	136,692	157,064
Intangible assets, Accumulated Amortization	69,472	73,977
Non-Competition Agreements
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Gross Carrying Amount	9,167	10,922
Intangible assets, Accumulated Amortization	8,275	9,051
Software
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Gross Carrying Amount	3,594	40,095
Intangible assets, Accumulated Amortization	613	33,625
Tradenames
Goodwill And Intangible Assets [Line Items]
Indefinite-lived intangible assets, Useful Life	Indefinite
Indefinite-lived intangible assets, Gross Carrying Amount	5,600	5,600
Finite lived intangible assets, Gross Carrying Amount	378	485
Intangible assets, Accumulated Amortization	$ 37	$ 365
Minimum
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	1 year
Minimum | Customer Relationships
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	1 year
Minimum | Non-Competition Agreements
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	1 year
Minimum | Software
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	3 years
Minimum | Tradenames
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	1 year
Maximum
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	15 years
Maximum | Customer Relationships
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	15 years
Maximum | Non-Competition Agreements
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	10 years
Maximum | Software
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	10 years
Maximum | Tradenames
Goodwill And Intangible Assets [Line Items]
Finite lived intangible assets, Useful Life in Years	2 years