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Share-based compensation - 2011 Director Plan (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Share-based compensation |  |  |  |
Income tax benefit | $ 0.2 | $ 0.3 | $ 0.9 | $ 1.2
Common stock |  |  |  |
Share-based compensation |  |  |  |
Shares granted (in shares) | 0 | 0 | 36,100 | 35,580
Fair value | $ 0.0 | $ 0.0 | $ 1.3 | $ 1.5
Income tax benefit | $ 0.0 | $ 0.0 | $ 0.3 | $ 0.4

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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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