CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Tennant Company Shareholders' Equity	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2024			18,849,456
Beginning balance at Dec. 31, 2024	$ 622.1	$ 620.8	$ 7.1	$ 76.7	$ 609.7	$ (72.7)	$ 1.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13.1	13.1			13.1
Other comprehensive loss	15.3	15.3				15.3
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings (in shares)			89,695
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings	(2.2)	(2.2)	$ (0.1)	(2.1)
Share-based compensation	3.2	3.2		3.2
Repurchases of common stock (in shares)			(235,866)
Repurchases of common stock, including excise tax	(20.2)	(20.2)		(20.2)
Dividends paid per common share	(5.6)	(5.6)			(5.6)
Other	0.4						0.4
Ending balance (in shares) at Mar. 31, 2025			18,703,285
Ending balance at Mar. 31, 2025	$ 626.1	624.4	$ 7.0	57.6	617.2	(57.4)	1.7
Beginning balance (in shares) at Dec. 31, 2025	17,846,681		17,846,681
Beginning balance at Dec. 31, 2025	$ 603.4	601.6	$ 6.7	0.0	628.1	(33.2)	1.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0.2	0.2			0.2
Other comprehensive loss	(4.1)	(4.1)				(4.1)
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings (in shares)			140,877
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings	(2.3)	(2.3)		(2.3)
Share-based compensation	1.5	1.5		1.5
Repurchases of common stock (in shares)			(949,770)
Repurchases of common stock, including excise tax	(60.0)	(60.0)	$ (0.3)	0.8	(60.5)
Dividends paid per common share	(5.5)	(5.5)			(5.5)
Other	$ (0.2)	(0.2)			(0.2)
Ending balance (in shares) at Mar. 31, 2026	17,037,788		17,037,788
Ending balance at Mar. 31, 2026	$ 533.0	$ 531.2	$ 6.4	$ 0.0	$ 562.1	$ (37.3)	$ 1.8