Energy Services Accounts Receivable Securitization Facility - Trade Receivables Transferred and Sold (Details) - ESFC - USD ($)	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Sep. 30, 2016
Accounts, Notes, Loans and Financing Receivable
Trade receivables transferred to ESFC during the period	$ 848,300,000	$ 615,300,000
ESFC trade receivables sold to the bank during the period	186,000,000	167,500,000
ESFC trade receivables - end of period	51,600,000	40,400,000	$ 35,700,000
Outstanding balance of trade receivables sold	$ 30,000,000	$ 0	$ 25,500,000