Weighted Average Shares Outstanding (Details) - shares	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Weighted Average Shares Outstanding [Line Items]
Basic (in shares)	51,213,518	52,304,190	54,073,407
Dilutive effect of:
Diluted (in shares)	51,633,169	52,831,606	54,605,298
Stock options [Member]
Dilutive effect of:
Antidilutive shares excluded form computation of earnings per share (in shares)	280,254	127,562	46,450
Stock options [Member]
Dilutive effect of:
Shares attributable to share-based payment arrangements (in shares)	176,984	260,240	258,052
Performance share awards [Member]
Dilutive effect of:
Shares attributable to share-based payment arrangements (in shares)	242,667	267,176	273,839

Weighted Average Shares Outstanding [Line Items]

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- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

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- Definition

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 28A
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- References

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- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
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- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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