Amortization Expense Associated with Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 1,900	$ 1,900	$ 1,800	$ 1,800	$ 1,700	$ 1,700	$ 1,700	$ 1,500	$ 11,917	[1]	$ 13,535	[1]	$ 6,944	[1]
Cost of revenues
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets									7,371		6,630		1,332
Selling, general and administrative expenses
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets									$ 4,546		$ 6,905		$ 5,612

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 7 to the consolidated financial statements.