Goodwill and Other Intangible Assets - Schedule of Carrying Value and Accumulated Amortization of Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, intangible assets	$ 4,066	$ 4,066
Accumulated Amortization, intangible assets	1,268	939
Customer list [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, intangible assets	3,500	3,500
Accumulated Amortization, intangible assets	922	631
Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount, intangible assets	566	566
Accumulated Amortization, intangible assets	$ 346	$ 308