Condensed Consolidated Statement of Equity (Unaudited) - USD ($) shares in Millions, $ in Millions		Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance at Dec. 31, 2018		$ 166.6	$ 49.7	$ 628.2	$ 429.1	$ (953.3)	$ 12.9
Beginning balance, Shares at Dec. 31, 2018			49.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		14.5			13.7		0.8
Other comprehensive income		2.2				1.9	0.3
Shares repurchased		0.0		(0.5)	0.5
Dividends to:
Brink’s common shareholders		(7.4)			(7.4)
Stock options and awards
Compensation expense		9.4		9.4
Other share-based benefit transactions		(6.0)	$ 0.2	(6.2)
Other share-based benefit transactions, shares			0.2
Ending balance at Mar. 31, 2019		$ 179.3	$ 49.9	630.9	464.7	(980.2)	14.0
Ending balance, Shares at Mar. 31, 2019			49.9
Stock options and awards
Dividends (dollars per share)		$ 0.15
Beginning balance at Dec. 31, 2018		$ 166.6	$ 49.7	628.2	429.1	(953.3)	12.9
Beginning balance, Shares at Dec. 31, 2018			49.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		35.2
Other comprehensive income		(22.1)				(22.8)
Ending balance at Sep. 30, 2019		185.2	$ 50.0	656.6	467.5	(1,004.9)	16.0
Ending balance, Shares at Sep. 30, 2019			50.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle	[1]	0.0			28.8	(28.8)
Beginning balance at Mar. 31, 2019		179.3	$ 49.9	630.9	464.7	(980.2)	14.0
Beginning balance, Shares at Mar. 31, 2019			49.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		14.0			12.5		1.5
Other comprehensive income		7.1				7.0	0.1
Dividends to:
Brink’s common shareholders		(7.5)			(7.5)
Noncontrolling interests		(0.2)					(0.2)
Stock options and awards
Compensation expense		16.7		16.7
Other share-based benefit transactions		0.2	$ 0.1	0.1
Other share-based benefit transactions, shares			0.1
Capital contributions from noncontrolling interest		0.1					0.1
Ending balance at Jun. 30, 2019		$ 209.7	$ 50.0	647.7	469.7	(973.2)	15.5
Ending balance, Shares at Jun. 30, 2019			50.0
Stock options and awards
Dividends (dollars per share)		$ 0.15
Net income		$ 6.7			5.4		1.3
Other comprehensive income		(31.4)				(31.7)	0.3
Brink’s common shareholders		(7.5)			(7.5)
Noncontrolling interests		(1.2)					(1.2)
Compensation expense		9.8		9.8
Other share-based benefit transactions		(1.0)		(0.9)	(0.1)
Capital contributions from noncontrolling interest		0.1					0.1
Ending balance at Sep. 30, 2019		$ 185.2	$ 50.0	656.6	467.5	(1,004.9)	16.0
Ending balance, Shares at Sep. 30, 2019			50.0
Stock options and awards
Dividends (dollars per share)		$ 0.15
Beginning balance at Dec. 31, 2019		$ 207.6	$ 50.1	663.3	457.4	(979.0)	15.8
Beginning balance, Shares at Dec. 31, 2019			50.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		2.8			1.8		1.0
Other comprehensive income		(117.4)				(117.0)	(0.4)
Dividends to:
Brink’s common shareholders		(7.5)			(7.5)
Noncontrolling interests		(0.7)					(0.7)
Stock options and awards
Compensation expense		7.2		7.2
Other share-based benefit transactions		(8.3)	$ 0.4	(8.6)	(0.1)
Other share-based benefit transactions, shares			0.4
Ending balance at Mar. 31, 2020		$ 82.0	$ 50.5	661.9	449.9	(1,096.0)	15.7
Ending balance, Shares at Mar. 31, 2020			50.5
Stock options and awards
Dividends (dollars per share)		$ 0.15
Beginning balance at Dec. 31, 2019		$ 207.6	$ 50.1	663.3	457.4	(979.0)	15.8
Beginning balance, Shares at Dec. 31, 2019			50.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		(4.5)
Other comprehensive income		(27.5)				(30.1)
Ending balance at Sep. 30, 2020		171.9	$ 49.4	660.0	389.7	(1,009.1)	81.9
Ending balance, Shares at Sep. 30, 2020			49.4
Beginning balance at Mar. 31, 2020		82.0	$ 50.5	661.9	449.9	(1,096.0)	15.7
Beginning balance, Shares at Mar. 31, 2020			50.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		15.2			12.9		2.3
Other comprehensive income		35.2				34.2	1.0
Dividends to:
Brink’s common shareholders		(7.6)			(7.6)
Noncontrolling interests		(7.2)					(7.2)
Stock options and awards
Compensation expense		5.4		5.4
Other share-based benefit transactions		0.1	$ 0.0	0.1
Other share-based benefit transactions, shares			0.0
Acquisitions with noncontrolling interests		(67.8)					(67.8)
Ending balance at Jun. 30, 2020		$ 190.9	$ 50.5	667.4	455.2	(1,061.8)	79.6
Ending balance, Shares at Jun. 30, 2020			50.5
Stock options and awards
Dividends (dollars per share)		$ 0.15
Net income		$ (22.5)			(23.9)		1.4
Other comprehensive income		54.7				52.7	2.0
Shares repurchased		(50.0)	$ (1.1)	(14.9)	(34.0)
Shares repurchased, shares			(1.1)
Brink’s common shareholders		(7.6)			(7.6)
Noncontrolling interests		(1.0)					(1.0)
Compensation expense		8.3		8.3
Other share-based benefit transactions		(0.8)		(0.8)
Acquisitions with noncontrolling interests		(0.1)					(0.1)
Ending balance at Sep. 30, 2020		$ 171.9	$ 49.4	$ 660.0	$ 389.7	$ (1,009.1)	$ 81.9
Ending balance, Shares at Sep. 30, 2020			49.4
Stock options and awards
Dividends (dollars per share)		$ 0.15

[1] Effective January 1, 2019, we adopted the provisions of ASU 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. We recognized a cumulative effect adjustment to January 1, 2019 retained earnings as a result of adopting this standard. See Note 1 for further details.