Acquisitions and Divestitures (Details 3) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Sales
Pro forma		$ 261,921		$ 777,832
As reported	$ 273,255	261,921	$ 838,299	723,771
Net Earnings (Loss) Attributable to Tennant Company
Pro forma		5,800		14,875
As reported	$ 9,676	$ 3,559	$ 25,694	$ (2,989)
Net Earnings (Loss) Attributable to Tennant Company per Share
Pro forma		$ 0.32		$ 0.84
As reported	$ 0.52	$ 0.20	$ 1.40	$ (0.17)

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

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Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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