Intangible and Other Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Intangible Assets Disclosure [Line Items]
Amortization expense for intangible assets	$ 1,131	$ 1,043	$ 560
Estimated amortization expense for intangible assets for year one	1,203
Estimated amortization expense for intangible assets for year two	1,136
Estimated amortization expense for intangible assets for year three	1,124
Estimated amortization expense for intangible assets for year four	1,019
Estimated amortization expense for intangible assets for year five	$ 820