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, 2017		$ 338.2	$ 50.5	$ 628.6	$ 564.9	$ (926.6)	$ 20.8
Beginning balance, Shares at Dec. 31, 2017			50.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		25.5			22.3		3.2
Other comprehensive income		12.2				11.1	1.1
Dividends to:
Brink’s common shareholders		(7.6)			(7.6)
Noncontrolling interests		(0.7)					(0.7)
Stock options and awards
Compensation expense		6.8		6.8
Other share-based benefit transactions		(10.1)	$ 0.4	(10.5)
Other share-based benefit transactions, shares			0.4
Ending balance at Mar. 31, 2018		366.5	$ 50.9	624.9	582.9	(916.6)	24.4
Ending balance, Shares at Mar. 31, 2018			50.9
Beginning balance at Dec. 31, 2017		338.2	$ 50.5	628.6	564.9	(926.6)	20.8
Beginning balance, Shares at Dec. 31, 2017			50.5
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		(63.3)
Other comprehensive income		9.8				9.7
Ending balance at Sep. 30, 2018		244.8	$ 50.6	633.9	456.7	(918.0)	21.6
Ending balance, Shares at Sep. 30, 2018			50.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principle	[1]	2.2			3.3	(1.1)
Beginning balance at Mar. 31, 2018		366.5	$ 50.9	624.9	582.9	(916.6)	24.4
Beginning balance, Shares at Mar. 31, 2018			50.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		(107.6)			(107.9)		0.3
Other comprehensive income		(11.4)				(10.4)	(1.0)
Dividends to:
Brink’s common shareholders		(7.6)			(7.6)
Noncontrolling interests		(1.2)					(1.2)
Stock options and awards
Compensation expense		5.7		5.7
Consideration from exercise of stock options		0.8	$ 0.0	0.8
Consideration from exercise of stock options, Shares			0.0
Other share-based benefit transactions		0.3	$ 0.1	0.2
Other share-based benefit transactions, shares			0.1
Dispositions of noncontrolling interests		(0.4)					(0.4)
Ending balance at Jun. 30, 2018		245.1	$ 51.0	631.6	467.4	(927.0)	22.1
Ending balance, Shares at Jun. 30, 2018			51.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		18.8			17.4		1.4
Other comprehensive income		9.0				9.0	0.0
Stock repurchased		(25.1)	$ (0.4)	(4.3)	(20.4)
Stock repurchased, Shares			(0.4)
Dividends to:
Brink’s common shareholders		(7.7)			(7.7)
Noncontrolling interests		(1.9)					(1.9)
Stock options and awards
Compensation expense		6.3		6.3
Other share-based benefit transactions		0.3	$ 0.0	0.3
Other share-based benefit transactions, shares			0.0
Ending balance at Sep. 30, 2018		244.8	$ 50.6	633.9	456.7	(918.0)	21.6
Ending balance, Shares at Sep. 30, 2018			50.6
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
Stock repurchased		0.0	$ 0.0	(0.5)	0.5
Stock repurchased, Shares			0.0
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
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		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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		6.7			5.4		1.3
Other comprehensive income		(31.4)				(31.7)	0.3
Dividends to:
Brink’s common shareholders		(7.5)			(7.5)
Noncontrolling interests		(1.2)					(1.2)
Stock options and awards
Compensation expense		9.8		9.8
Other share-based benefit transactions		(1.0)	$ 0.0	(0.9)	(0.1)
Other share-based benefit transactions, shares			0.0
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

[1] Effective January 1, 2018, we adopted the provisions of ASU 2014-09, Revenue From Contracts with Customers, ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory. We recognized a cumulative effect adjustment to January 1, 2018 retained earnings as a result of adopting each of these standards. See Note 1 for further details of the impact of each standard.