CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) - USD ($)	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, 2021			18,535,116
Beginning balance at Dec. 31, 2021	$ 435,100,000	$ 433,800,000	$ 7,000,000.0	$ 54,100,000	$ 410,600,000	$ (37,900,000)	$ 1,300,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	10,300,000	10,300,000			10,300,000
Other comprehensive income (loss)	(4,000,000.0)	(4,000,000.0)				(4,000,000.0)
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings and repurchases (in shares)			44,700
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings and repurchases	(1,300,000)	(1,300,000)	$ 0	(1,300,000)
Share-based compensation	1,800,000	1,800,000		1,800,000
Dividends paid per common share	(4,600,000)	(4,600,000)			(4,600,000)
Ending balance (in shares) at Mar. 31, 2022			18,579,816
Ending balance at Mar. 31, 2022	$ 437,300,000	436,000,000.0	$ 7,000,000.0	54,600,000	416,300,000	(41,900,000)	1,300,000
Beginning balance (in shares) at Dec. 31, 2022	18,521,485		18,521,485
Beginning balance at Dec. 31, 2022	$ 472,100,000	470,800,000	$ 7,000,000.0	56,000,000.0	458,000,000.0	(50,200,000)	1,300,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,300,000	24,300,000			24,300,000
Other comprehensive income (loss)	4,700,000	4,700,000				4,700,000
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings and repurchases (in shares)			93,073
Issue stock for directors, employee benefit and stock plans, net of related tax withholdings and repurchases	800,000	800,000		800,000
Share-based compensation	1,200,000	1,200,000		1,200,000
Repurchases of common stock	(5,000,000.0)	(5,000,000.0)	$ (73,525)	(5,000,000.0)
Dividends paid per common share	$ (4,900,000)	(4,900,000)			(4,900,000)
Ending balance (in shares) at Mar. 31, 2023	18,541,033		18,541,033
Ending balance at Mar. 31, 2023	$ 493,200,000	$ 491,900,000	$ 7,000,000.0	$ 53,000,000.0	$ 477,400,000	$ (45,500,000)	$ 1,300,000