Maximum excess availability level at which financial maintenance covenants would apply.

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Maximum excess availability level at which financial maintenance covenants would apply, as a percentage of aggregate commitments.

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Total other amounts reducing excess availability.

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Potential increase in the size of credit facility.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Amount of interest capitalized during the period.

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Date the credit facility terminates, in CCYY-MM-DD format.

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The effective interest rate at the end of the reporting period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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Borrowing Arrangements (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018	Jun. 12, 2018	Sep. 30, 2017
Agreement termination date				Jul. 13, 2021
Cash and cash equivalents	$ 140.7	$ 331.5		$ 140.7	$ 331.5	$ 347.1		$ 361.7
Future maturities of outstanding borrowings
Loss on early extinguishment of debt	0.0	6.2		0.0	6.2
Payments of Debt Issuance Costs				0.0	$ 6.6
Interest Costs Capitalized				1.2
Domestic Line of Credit [Member]
Revolving credit facility amount			$ (175.0)
Potential increase size of the credit facility by an additional amount			$ 150.0
Line of Credit Facility, Interest Rate at Period End			12500.00%
Aggregate commitments availability			$ 17.5
Aggregate commitments availability, percentage			10.00%
Outstanding letter of credit accrued fees and expenses	16.4			16.4
Excess availability reduced by outstanding borrowings, outstanding letters of credit and accrued fees and expenses	136.4			136.4
Unsecured Debt [Member]
Long-term Debt, Gross							$ 450.0
Future maturities of outstanding borrowings
Payments of Debt Issuance Costs		$ 6.6
Swing Line Loans [Member]
Revolving credit facility amount			$ (25.0)
Letters Of Credit Outstanding [Member]
Revolving credit facility amount			$ (60.0)
Bonds [Member]
Debt Instrument, Interest Rate, Effective Percentage			5.50%
Future maturities of outstanding borrowings
Financial Liabilities Fair Value Disclosure	$ 465.8			$ 465.8
Minimum [Member] \| Domestic Line of Credit [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage			2500.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member] \| Long-term Debt [Member]
Debt Instrument, Basis Spread on Variable Rate			2500.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member] \| Domestic Line of Credit [Member]
Debt Instrument, Basis Spread on Variable Rate			12500.00%
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member] \| Domestic Line of Credit [Member]
Debt Instrument, Basis Spread on Variable Rate			15000.00%
Base Rate [Member] \| Maximum [Member] \| Domestic Line of Credit [Member]
Debt Instrument, Basis Spread on Variable Rate			5000.00%