Acquisitions - Narrative (Details) - USD ($)			1 Months Ended					3 Months Ended			6 Months Ended	9 Months Ended		12 Months Ended
	Jan. 01, 2019	Apr. 03, 2017	Apr. 30, 2018	Feb. 28, 2018	Jan. 31, 2018	Apr. 30, 2017	Dec. 31, 2016	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2017	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Cash paid for business acquisition												$ 11,000,000	$ 63,500,000
Transaction related costs								$ 0		$ 200,000		$ 100,000	1,300,000
Non-compete agreements | Minimum
Business Acquisition [Line Items]
Weighted average useful life												3 years
Non-compete agreements | Maximum
Business Acquisition [Line Items]
Weighted average useful life												10 years
Ultra Chem
Business Acquisition [Line Items]
Cash paid for business acquisition		$ 56,700,000
Cash acquired from acquisition		500,000
Purchase price held in escrow								9,300,000				$ 9,300,000
Maximum holding period in escrow												5 years
Contingent consideration		$ 0
Transaction related costs								$ 0		$ 300,000		$ 100,000	$ 1,200,000
Reduction in gross receivables acquired												$ 1,500,000
Increase (decrease) in inventory														$ 1,000,000
Sales and operating revenue from acquiree									$ 19,800,000		$ 40,400,000
Net income from acquiree									$ 100,000		300,000
Ultra Chem | Customer-related intangible
Business Acquisition [Line Items]
Intangible asset, amortization period		10 years
Definite-lived intangible assets		$ 24,000,000
Ultra Chem | Trade names
Business Acquisition [Line Items]
Intangible asset, amortization period		2 years
Definite-lived intangible assets		$ 300,000
Ultra Chem | Non-compete agreements
Business Acquisition [Line Items]
Intangible asset, amortization period		3 years
Definite-lived intangible assets		$ 3,900,000
Ultra Chem | ABL Facility
Business Acquisition [Line Items]
Borrowings used for acquisition		$ 58,000,000
Other Intangible Assets
Business Acquisition [Line Items]
Payment for intangible assets			$ 3,000,000		$ 1,700,000		$ 5,100,000				$ 6,000,000
Finite-lived Intangible Assets Acquired						$ 1,100,000
Recognized intangible assets							8,500,000
Weighted average useful life						5 years
Total consideration				$ 9,000,000		$ 1,900,000	$ 8,500,000
Payments made at closing						$ 1,600,000
Other Intangible Assets | Minimum
Business Acquisition [Line Items]
Weighted average useful life				5 years			10 years
Other Intangible Assets | Maximum
Business Acquisition [Line Items]
Weighted average useful life				13 years			13 years
Forecast | Other Intangible Assets
Business Acquisition [Line Items]
Payment for intangible assets	$ 1,700,000