Debt (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term debt, gross	$ 198.0	$ 197.0
Less: unamortized debt issuance costs	0.7	0.7
Debt, current	0.0	0.0
Long-term debt, excluding current portion	198.0	197.0
Revolving credit facility, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	30.6	29.6
Line of credit facility, current borrowing capacity	300.0
Line of credit facility outstanding borrowings, Yen	4.7
Line of credit facility outstanding borrowings, Euro	25.9
Letters of credit outstanding	2.8
Line of credit facility, remaining borrowing capacity	266.6
Notes payable, Due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	0.1	0.1
Series A Notes, Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	42.0	42.0
Series B Notes, Due 2024 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	53.0	53.0
Series C Notes, Due 2027 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 73.0	$ 73.0

Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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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.

+ 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.

+ Details

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- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

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

+ References

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- Definition

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.

+ References

+ Details

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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

+ Details

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- Definition

Line of credit facility outstanding borrowings, Euro

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- Definition

Line of credit facility outstanding borrowings, Yen

+ References

No definition available.

+ Details

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