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

No definition available.

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- Definition

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

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- Definition

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

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

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

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

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- Definition

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

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- Definition

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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No definition available.

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- Definition

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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- Definition

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

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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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- Definition

The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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- Definition

Represents the minimum base rate to be used as the reference rate.

+ References

No definition available.

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The extension period for the term of the credit facility.

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No definition available.

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- Definition

Represents the maximum amount of the guarantees available through letters of credit.

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No definition available.

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Financing Arrangements - Credit Agreement (Details) - USD ($)				1 Months Ended	12 Months Ended
	Jun. 18, 2020	Apr. 24, 2020	Feb. 12, 2016	Feb. 29, 2016	Dec. 31, 2020	Apr. 23, 2020	Dec. 31, 2019	Apr. 24, 2016	Apr. 23, 2016
Credit Agreement
Borrowings outstanding					$ 200,000,000.0		$ 310,000,000.0
Term Loan due February 2021
Credit Agreement
Borrowings outstanding							225,000,000.0
Letters of credit
Credit Agreement
Term of debt					1 year
Stand-by letters of credit outstanding					$ 16,200,000		25,800,000
5.05% Senior notes due 2020
Credit Agreement
Borrowings outstanding							$ 75,000,000.0
Interest rate (as a percent)							5.05%
Credit Agreement
Credit Agreement
Borrowing capacity		$ 100,000,000
Term of debt			5 years
Sublimit on letters of credit			$ 100,000,000
Eurocurrency rate loans \| LIBOR
Credit Agreement
Minimum base rate (as a percent)		$ 1.00
Eurocurrency rate loans \| LIBOR \| Minimum
Credit Agreement
Interest rate added to base rate (as a percent)		1.50%
Eurocurrency rate loans \| LIBOR \| Maximum
Credit Agreement
Interest rate added to base rate (as a percent)		2.10%
Base rate loans and swing line loans
Credit Agreement
Minimum base rate (as a percent)		$ 2.00
Base rate loans and swing line loans \| LIBOR
Credit Agreement
Interest rate (as a percent)		1.00%
Base rate loans and swing line loans \| Prime Rate
Credit Agreement
Interest rate (as a percent)		0.50%
Revolving credit facility
Credit Agreement
Borrowing capacity		$ 800,000,000	$ 500,000,000			$ 500,000,000		$ 800,000,000	$ 500,000,000
Extension period		1 year
Interest rate on revolving credit facility (as a percent)					2.50%
Amount drawn					$ 200,000,000.0
Unused and available credit under the credit agreement					583,800,000
Stand-by letters of credit outstanding					$ 16,200,000
Term loan facility \| Term Loan due February 2021
Credit Agreement
Term of debt			5 years
Face amount			$ 300,000,000
Amount drawn				$ 300,000,000
Notes Purchase Agreement 2010 \| Revolving credit facility
Credit Agreement
Repayment of debt	$ 35,000,000.0
Notes Purchase Agreement 2010 \| Senior notes
Credit Agreement
Face amount	75,000,000.0
Amount drawn	$ 40,000,000.0
Swing Line Loans
Credit Agreement
Borrowing capacity		$ 15,000,000