Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Earnings Including Noncontrolling Interest	$ 14.8	$ 5.4	$ 12.7	$ 3.3	$ 20.2	$ 16.1
Other Comprehensive (Loss) Income:
Foreign currency translation adjustments	1.3		(19.5)		(0.9)	(11.1)
Pension and retiree medical benefits	0.0		0.0		0.0	0.1
Cash flow hedge	1.3		1.4		2.7	(1.3)
Income Taxes:
Foreign currency translation adjustments	0.1		0.3		0.0	0.2
Pension and retiree medical benefits	0.0		0.0		0.0	(0.2)
Cash flow hedge	(0.3)		(0.3)		(0.7)	(0.8)
Total Other Comprehensive (Loss) Income, net of tax	2.4		(18.1)		1.1	(13.1)
Total Comprehensive Income Including Noncontrolling Interest	17.2		(5.4)		21.3	3.0
Comprehensive Income Attributable to Noncontrolling Interest	0.0		0.0		0.0	0.1
Comprehensive Income Attributable to Tennant Company	$ 17.2		$ (5.4)		$ 21.3	$ 2.9