Amortization Expense of Other Intangible Assets (Detail) (Other Intangible Assets, USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 903	$ 1,113	$ 3,024	$ 3,854