Derivatives - Summary of Gains and Losses (Net of Reclassifications Into Income) (Details) - Interest Rate Swap - Designated as Hedging Instrument - Cash Flow Hedging - USD ($) $ in Millions	2 Months Ended	3 Months Ended	8 Months Ended	9 Months Ended
	Jun. 08, 2016	Jun. 30, 2017	Jun. 08, 2016	Jun. 30, 2017
Interest expense | Successor
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative instruments		$ (1.2)		$ (1.5)
Interest expense | Predecessor
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative instruments	$ (0.1)		$ (0.3)
Other comprehensive income(loss) | Successor
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative instruments		$ (0.7)		$ (0.4)
Other comprehensive income(loss) | Predecessor
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gain (loss) on derivative instruments	$ 0.1		$ 0.3