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

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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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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Weighted average interest rate of debt outstanding.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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The carrying amount of the asset transferred to a third party to serve as a deposit, which typically serves as security against failure by the transferor to perform under terms of an agreement.

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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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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Fair value portion of contractual arrangement with a lender under which borrowings can be made up to a specific amount at any point in time.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying amount of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists, and for which a claim has been made or is probable of being asserted, typically arising from workmen's compensation-type of incidents and personal injury to nonemployees from accidents on the entity's property that are expected to be paid within one year (or the normal operating cycle, if longer).

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Financing Arrangements (Details) $ in Thousands, £ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2019 GBP (£)	Feb. 02, 2016 USD ($)	Jul. 17, 2015 USD ($)	Mar. 31, 2013 USD ($)
Financial arrangement
Long-term debt, gross		$ 200,000	$ 200,000
Less unamortized debt issuance costs		(175)	(207)
Less current portion		(10,714)
Long-term debt		189,111	199,793
Maturities of long-term debt
2020		10,700
2021		35,700
2022		35,700
2023		35,700
2024		35,700
Amount of interest paid		16,800	10,000	$ 14,800
Short term borrowings
Borrowings outstanding		39,900
Letters of Credit and bank guarantees outstanding		39,900
Self-insurance liabilities		7,400	$ 8,600
Letters of credit primarily for self-insured liabilities
Short term borrowings
Letters of Credit and bank guarantees outstanding		5,500
Fair value of instruments		0
United Kingdom
Short term borrowings
Maximum borrowing capacity under credit agreement		24,600			£ 20.0
Borrowings outstanding		0
Cash on deposit as collateral		$ 19,500
Senior unsecured notes
Financial arrangement
Interest rate (as a percent)								3.35%
Principal amount of debt instrument								$ 100,000
Short term borrowings
Variable interest rate (as a percent)		0.50%
Series A senior unsecured notes
Financial arrangement
Interest rate (as a percent)		3.35%	3.35%		3.35%
Long-term debt, gross		$ 50,000	$ 50,000
Series B senior unsecured notes
Financial arrangement
Interest rate (as a percent)		3.35%	3.35%		3.35%
Long-term debt, gross		$ 50,000	$ 50,000
Series C senior unsecured notes
Financial arrangement
Interest rate (as a percent)		3.70%	3.70%		3.70%		3.70%
Long-term debt, gross		$ 25,000	$ 25,000
Principal amount of debt instrument							$ 25,000
Series D senior unsecured notes
Financial arrangement
Interest rate (as a percent)		3.93%	3.93%		3.93%	3.93%
Long-term debt, gross		$ 75,000	$ 75,000
Principal amount of debt instrument						$ 75,000
Revolving credit agreement
Short term borrowings
Maximum borrowing capacity under credit agreement	$ 400,000	800,000
Borrowings outstanding		195,500
Letters of credit outstanding		31,500
Available amount under line of credit		$ 573,000
Weighted average interest rate on outstanding borrowings		3.90%			3.90%
Debt issuance costs incurred	$ 1,900
Unamortized debt issuance costs		$ 1,200
Revolving credit agreement \| Letters of credit and bank guarantees
Short term borrowings
Letters of credit outstanding		$ 31,500
Revolving credit agreement \| LIBOR \| Minimum
Short term borrowings
Variable interest rate (as a percent)		1.00%
Revolving credit agreement \| LIBOR \| Maximum
Short term borrowings
Variable interest rate (as a percent)		2.00%
Revolving credit agreement \| Alternate Base Rate
Short term borrowings
Variable interest rate (as a percent)		0.50%
Revolving credit agreement \| Adjusted LIBOR Rate
Short term borrowings
Variable interest rate (as a percent)		1.00%
Revolving credit agreement \| Adjusted LIBOR Rate \| Minimum
Short term borrowings
Margin interset rate (as a percent)		0.00%
Revolving credit agreement \| Adjusted LIBOR Rate \| Maximum
Short term borrowings
Margin interset rate (as a percent)		1.00%
Other credit facility
Short term borrowings
Letters of credit outstanding		$ 8,400
Letter of credit agreement \| Performance guarantee
Short term borrowings
Letters of credit outstanding		$ 34,400