Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Jun. 30, 2017	Apr. 03, 2017	Sep. 30, 2016	Jun. 09, 2016
Business Acquisition [Line Items]
Goodwill	$ 694.2		$ 665.7
Ultra Chem
Business Acquisition [Line Items]
Accounts receivable		$ 14.4
Inventory		10.5
Other current assets		2.0
Property, plant and equipment		0.4
Other non-current assets		0.4
Goodwill		22.5
Total assets acquired		76.2
Short-term borrowings		0.9
Accounts payable		13.0
Other current liabilities		4.1
Other non-current liabilities		1.4
Total liabilities assumed		19.4
Net assets acquired		56.8
Ultra Chem | Customer-related intangible
Business Acquisition [Line Items]
Finite-lived intangible assets		22.0
Ultra Chem | Trade name
Business Acquisition [Line Items]
Finite-lived intangible assets		0.3
Ultra Chem | Non-compete agreements
Business Acquisition [Line Items]
Finite-lived intangible assets		$ 3.7
Nexeo Solutions Inc.
Business Acquisition [Line Items]
Accounts receivable				$ 470.0
Inventory				327.9
Other current assets				26.0
Property, plant and equipment				328.2
Other non-current assets				3.2
Deferred tax assets				1.2
Goodwill				673.4
Total assets acquired				2,052.6
Short-term borrowings and current portion of capital leases				40.6
Accounts payable				335.9
Other current liabilities				52.8
Long-term portion of capital leases				23.0
Long-term debt				767.3
Deferred tax liability				24.8
Other non-current liabilities				5.5
Total liabilities assumed				1,249.9
Net assets acquired				802.7
Nexeo Solutions Inc. | Customer-related intangible
Business Acquisition [Line Items]
Finite-lived intangible assets				201.0
Nexeo Solutions Inc. | Trade name
Business Acquisition [Line Items]
Finite-lived intangible assets				21.0
Nexeo Solutions Inc. | Below-market leases
Business Acquisition [Line Items]
Finite-lived intangible assets				$ 0.7