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v3.20.2

Borrowing Arrangements (Narrative) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2020 | Sep. 30, 2019
Debt Instrument [Line Items] |  |
Long-Term Debt, Maturity, Year One | $ 1.1 |
Long-Term Debt, Maturity, Year Two | 0.9 |
Long-Term Debt, Maturity, Year Three | 0.5 |
Long-Term Debt, Maturity, Year Four | 0.1 |
Long-Term Debt, Maturity, Year Five | $ 0.0 |
Line of Credit Facility, Expiration Date | Jul. 29, 2025 |
Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Line of Credit Facility, Maximum Borrowing Capacity |  | $ 175.0
Potential Increase In The Size Of Credit Facility | $ 150.0 |
Line of Credit Facility, Interest Rate at Period End | 200.00% |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | 37.50% |
Maximum excess availability level at which financial maintenance covenants would apply | $ 17.5 |
Maximum excess availability level at which financial maintenance covenants would apply, as a percentage of aggregate commitments | 10.00% |
Outstanding Letter Of Credit Accrued Fees And Expenses | $ 14.1 |
Line of Credit Facility, Remaining Borrowing Capacity | 133.9 |
Outstanding Letter Of Credit Accrued Fees And Expenses | 14.1 |
Line of Credit Facility, Remaining Borrowing Capacity | 133.9 |
Potential Increase In The Size Of Credit Facility | $ 150.0 |
Line of Credit Facility, Maximum Borrowing Capacity |  | $ 175.0
Line of Credit Facility, Interest Rate at Period End | 200.00% |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | 37.50% |
Maximum excess availability level at which financial maintenance covenants would apply | $ 17.5 |
Maximum excess availability level at which financial maintenance covenants would apply, as a percentage of aggregate commitments | 10.00% |
Bonds [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Interest Rate, Effective Percentage |  | 5.50%
Financial Liabilities Fair Value Disclosure | $ 465.8 |
Financial Liabilities Fair Value Disclosure | 465.8 |
Debt Instrument, Interest Rate, Effective Percentage |  | 5.50%
Unsecured Debt [Member] |  |
Debt Instrument [Line Items] |  |
Payments of Debt Issuance Costs |  | $ 6.6
Payments of Debt Issuance Costs |  | $ 6.6
Swing Line Loans [Member] |  |
Debt Instrument [Line Items] |  |
Line of Credit Facility, Maximum Borrowing Capacity | 25.0 |
Line of Credit Facility, Maximum Borrowing Capacity | 25.0 |
Letter Of Credit [Member] |  |
Debt Instrument [Line Items] |  |
Line of Credit Facility, Maximum Borrowing Capacity | 60.0 |
Line of Credit Facility, Maximum Borrowing Capacity | $ 60.0 |
Secured Debt [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate |  | 250.00%
Long-term Debt, Gross |  | $ 500.0
Long-term Debt, Gross |  | $ 500.0
Debt Instrument, Basis Spread on Variable Rate |  | 250.00%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 200.00% |
Debt Instrument, Basis Spread on Variable Rate | 200.00% |
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Secured Debt [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Interest Rate, Stated Percentage |  | 0.75%
Debt Instrument, Interest Rate, Stated Percentage |  | 0.75%
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member] | Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 225.00% |
Debt Instrument, Basis Spread on Variable Rate | 225.00% |
Base Rate [Member] | Minimum [Member] | Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 100.00% |
Debt Instrument, Basis Spread on Variable Rate | 100.00% |
Base Rate [Member] | Maximum [Member] | Revolving Credit Facility [Member] |  |
Debt Instrument [Line Items] |  |
Debt Instrument, Basis Spread on Variable Rate | 125.00% |
Debt Instrument, Basis Spread on Variable Rate | 125.00% |

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