Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Intangible Assets And Goodwill [Line Items]
Goodwill	$ 56,324,000	$ 44,668,000	$ 28,354,000
Other Intangible assets	50,892,000	33,050,000
Amortization of intangible expenses	2,787,000	1,018,000
Estimated amortization expense for 2013	4,222,000
Estimated amortization expense for 2014	4,222,000
Estimated amortization expense for 2015	4,222,000
Estimated amortization expense for 2016	4,198,000
Estimated amortization expense for 2017	3,901,000
Estimated amortization expense for intangible assets thereafter	$ 3,436,000