Restructuring and Other Charges, net (Accrual Activity Relating to Restructuring and Other Charges) (Detail) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Restructuring [Roll Forward]
Balance at September 30, 2018	$ 16,935
Restructuring charges	10,389	$ 5,316
Restructuring Reserve, Accrual Adjustment	(23)
Cash payments	(12,261)
Balance at December 31, 2018	15,040
Personnel
Restructuring [Roll Forward]
Balance at September 30, 2018	9,320
Restructuring charges	8,483	3,660
Restructuring Reserve, Accrual Adjustment	0
Cash payments	(9,489)
Balance at December 31, 2018	8,314
Facilities
Restructuring [Roll Forward]
Balance at September 30, 2018	7,615
Restructuring charges	1,906	$ 1,656
Restructuring Reserve, Accrual Adjustment	(23)
Cash payments	(2,772)
Balance at December 31, 2018	$ 6,726

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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