Stock-based Compensation Plans and Awards - Stock Options Activity (Details) shares in Thousands	9 Months Ended
Sep. 30, 2018 shares
Stock option activity
Outstanding beginning balance (in shares)	2,140
Options granted (in shares)	47
Options exercised (in shares)	(237)
Options forfeited or cancelled (in shares)	(30)
Outstanding ending balance (in shares)	1,920

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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- Definition

Gross number of share options (or share units) granted during the period.

+ References

No definition available.

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- Definition

Number of options outstanding, including both vested and non-vested options.

+ References

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-Publisher FASB
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Number of share options (or share units) exercised during the current period.

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