Shareholders' Equity (Narrative) (Details) $ in Millions	9 Months Ended
Sep. 30, 2019 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares repurchased \| shares	77,991
Stock repurchased value	$ 81.1
August 2019 share repurchase program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, authorized amount	$ 300.0
Number of common stock shares repurchased \| shares	4,620
Stock repurchased value	$ 5.4
May 2018 share repurchase program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock shares repurchased \| shares	73,371
Stock repurchased value	$ 75.8
Cumulative stock repurchased shares \| shares	93,036
Cumulative stock repurchased value	$ 97.2

The cumulative number of shares that have been repurchased and have not been retired and are not held in treasury.

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The cumulative equity impact of the value of stock that has been repurchased and has not been retired and is not held in treasury.

+ References

No definition available.

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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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Amount of stock repurchase plan authorized.

+ References

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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