Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	$ 55,012	$ 54,451
Accumulated amortization	(14,493)	(12,138)
Net intangible assets	40,519	42,313
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	51,174	51,603
Accumulated amortization	(13,576)	(11,717)
Net intangible assets	37,598	39,886
Other Intangibles
Finite-Lived Intangible Assets [Line Items]
Gross intangible assets	3,838	2,848
Accumulated amortization	(917)	(421)
Net intangible assets	$ 2,921	$ 2,427