Goodwill and Intangible Assets - Amortization Expense Associated with Intangible Assets (Detail) - USD ($) $ in Thousands		3 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	[1]	$ 3,320	$ 3,580
Cost of revenues
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets		1,686	1,907
Selling, general and administrative expenses
Finite-Lived Intangible Assets [Line Items]
Amortization expense of intangible assets		$ 1,634	$ 1,673

[1] Cost of revenues and selling, general and administrative expenses exclude the amortization of intangible assets. See Note 4.