Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2015
Operating Loss Carryforwards [Line Items]
Effective income tax rate reconciliation, percent		38.30%	0.00%
Income tax expense (benefit)	$ 3.5	$ 4.6
Deferred tax assets not to be utilized in future period	$ 7.2	$ 7.2
Prior to September 30, 2015 [Member]
Operating Loss Carryforwards [Line Items]
Income tax expense (benefit)				$ 0.0
Percentage of valuation allowance, deferred tax assets				100.00%