Estimated Amortization of Identified Intangible Assets for Next Five Years (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012
Expected Amortization Expense [Line Items]
Finite-Lived Intangible Assets, Amortization Expense, Year One	$ 349
Estimated amortization of identified intangible assets, year ending December 31, 2013	349
Estimated amortization of identified intangible assets, year ending December 31, 2014	349
Estimated amortization of identified intangible assets, year ending December 31, 2015	251
Estimated amortization of identified intangible assets, year ending December 31, 2016	$ 87