Income Taxes Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Contingency [Line Items]
Income tax provision	$ 220	$ 3,340	$ 75,070	$ 1,790
Reductions in unrecognized tax benefits from expiration	300			900
Establishment of a valuation allowance	79,300
Income tax benefit resulted from reinstatement of tax credit				$ 900
Minimum
Income Tax Contingency [Line Items]
Anticipated unrecognized tax benefit reduction during next twelve months	$ 1,200		$ 1,200