Amortization Expense Associated with Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Mar. 31, 2012		Mar. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 1,490	[1]	$ 1,933	[1]	$ 3,420	[1]	$ 3,862	[1]
Cost of revenues
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	128		568		697		1,137
Selling, general and administrative expenses
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 1,362		$ 1,365		$ 2,723		$ 2,725

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 4 to the accompanying condensed consolidated financial statements.