Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Amortization Expense [Line Items]
Amortization expense for other intangible assets total	$ 12,991	$ 6,774	$ 4,737	$ 3,644	$ 2,861