Debt (Details) - USD ($) $ in Millions		Jun. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Total long-term debt, including current maturities		$ 1,281.4	$ 1,525.4
Current maturities of long-term debt		184.9	0.0
Long-term debt		1,096.5	1,525.4
Notes payable		20.9	19.4
Senior notes | Senior notes due 2021
Debt Instrument [Line Items]
Total long-term debt, including current maturities	[1]	598.6	598.3
Unamortized debt issuance costs		1.4	1.7
Senior notes | Senior notes due 2022
Debt Instrument [Line Items]
Total long-term debt, including current maturities	[1],[2]	497.9	497.4
Unamortized debt issuance costs		1.6	1.9
Unamortized discount		0.5	0.7
Domestic line of credit
Debt Instrument [Line Items]
Total long-term debt, including current maturities		0.0	245.0
Loans payable
Debt Instrument [Line Items]
Total long-term debt, including current maturities	[1]	184.9	184.7
Unamortized debt issuance costs		$ 0.1	$ 0.3

[1] At June 30, 2018, the balance for the senior notes due 2021, the senior notes due 2022 and the term loan are reflected net of debt issuance costs of $1.4, $1.6 and $0.1, respectively. At September 30, 2017, the balance for the senior notes due 2021, the senior notes due 2022 and the term loan are reflected net of debt issuance costs of $1.7, $1.9 and $0.3, respectively.

[2] At June 30, 2018 and September 30, 2017, the balance for the senior notes due 2022 is reflected net of discounts of $0.5 and $0.7, respectively.