Income Taxes (Additional Information) (Detail) (USD $)	3 Months Ended		9 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2013
Business Acquisition [Line Items]
Income taxes associated with uncertain tax position	$ 21,100,000		$ 21,100,000		$ 19,600,000
U.S. federal statutory income tax rate			35.00%	35.00%
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	1,000,000		(2,800,000)
Effective tax rate	(14.70%)	(338.10%)	(12.30%)	(29.90%)
Provision for income taxes	$ 6,959,000	$ 26,990,000	$ 16,331,000	$ 19,103,000