Fair Value Measurements - Narrative (Details) $ in Millions	1 Months Ended	9 Months Ended
	Mar. 31, 2017 USD ($) interest_rate_swap	Jun. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Measurement period adjustment		$ 5.6
Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Early termination payment	$ 0.3
Cash Flow Hedging | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Number of new swaps entered into to manage interest rate exposure | interest_rate_swap	4
Level 2 | Cash Flow Hedging | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Number of new swaps entered into to manage interest rate exposure | interest_rate_swap	4
Level 2 | Cash Flow Hedging | Interest Rate Swap | Other non-current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative asset		0.1	$ 0.0
Level 2 | Cash Flow Hedging | Interest Rate Swap | Accrued expenses and other liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative liability		1.5	0.0
Level 2 | Cash Flow Hedging | Interest Rate Swap | Other non-current liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative liability		0.4	0.0
TRA Liability
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Measurement period adjustment		5.6
Nexeo Solutions Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration - Fair value of Deferred Cash Consideration		40.4	35.0
Contingent consideration - Fair value of TRA		$ 103.4	$ 83.4