Intangible and Other Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Intangible Assets Disclosure [Line Items]
Amortization expense for intangible assets	$ 1,224	$ 1,131	$ 1,043
Estimated amortization expense for intangible assets for year one	1,117
Estimated amortization expense for intangible assets for year two	1,105
Estimated amortization expense for intangible assets for year three	1,030
Estimated amortization expense for intangible assets for year four	784
Estimated amortization expense for intangible assets for year five	$ 638