Accrued Expenses and Other Current Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012		Sep. 30, 2011
Schedule of Accrued Liabilities [Line Items]
Compensation	$ 101,214		$ 97,929
Professional fees	12,969		11,975
Income taxes payable	10,777		4,240
Acquisition-related costs and liabilities	10,270		8,414
Cost of revenue related liabilities	10,358		8,698
Sales and marketing incentives	10,155	[1]	16,253	[1]
Sales and other taxes payable	9,967		9,876
Accrued interest payable	5,915		977
Accrued business combination costs	1,766		8,275
Other	7,891		9,437
Total	$ 181,282		$ 176,074

[1] Included in accrued sales and marketing incentives as of September 30, 2011, is a €5.0 million fixed obligation assumed in connection with our acquisition of SpinVox in 2009. At September 30, 2011, we had €5.0 million ($6.8 million equivalent) of restricted cash that has been placed in an irrevocable standby letter of credit related to the liability. The restricted cash was released upon the settlement of the liability during the three months ended December 31, 2011.