Condensed Consolidated Statement of Equity (Unaudited) - USD ($) $ in Millions		Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance at Dec. 31, 2016		$ 354.8	$ 50.0	$ 618.1	$ 576.0	$ (907.0)	$ 17.7
Beginning balance, Shares at Dec. 31, 2016			50,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		40.5			34.7		5.8
Other comprehensive income		34.3				33.2	1.1
Dividends to:
Brink’s common shareholders		(5.0)			(5.0)
Noncontrolling interests		(0.2)					(0.2)
Share-based compensation:
Compensation expense		4.5		4.5
Consideration from exercise of stock options		0.7	$ 0.0	0.7
Consideration from exercise of stock options, Shares			0
Other share-based benefit transactions		(8.4)	$ 0.4	(8.8)
Other share-based benefit transactions, shares			400,000
Ending balance at Mar. 31, 2017		421.2	$ 50.4	614.5	605.7	(873.8)	24.4
Ending balance, Shares at Mar. 31, 2017			50,400,000
Beginning balance at Dec. 31, 2016		354.8	$ 50.0	618.1	576.0	(907.0)	17.7
Beginning balance, Shares at Dec. 31, 2016			50,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		75.1
Other comprehensive income		68.2				66.8
Ending balance at Sep. 30, 2017		480.3	$ 50.5	623.5	624.6	(840.2)	21.9
Ending balance, Shares at Sep. 30, 2017			50,500,000
Beginning balance at Mar. 31, 2017		421.2	$ 50.4	614.5	605.7	(873.8)	24.4
Beginning balance, Shares at Mar. 31, 2017			50,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		13.5			14.2		(0.7)
Other comprehensive income		12.2				14.0	(1.8)
Dividends to:
Brink’s common shareholders		(7.6)			(7.6)
Noncontrolling interests		(2.4)					(2.4)
Share-based compensation:
Compensation expense		4.0		4.0
Consideration from exercise of stock options		1.9	$ 0.0	1.9
Consideration from exercise of stock options, Shares			0
Ending balance at Jun. 30, 2017		442.8	$ 50.4	620.4	612.3	(859.8)	19.5
Ending balance, Shares at Jun. 30, 2017			50,400,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		21.1			19.9		1.2
Other comprehensive income		21.7				19.6	2.1
Dividends to:
Brink’s common shareholders		(7.5)			(7.5)
Noncontrolling interests		(0.9)					(0.9)
Share-based compensation:
Compensation expense		4.0		4.0
Consideration from exercise of stock options		0.1	$ 0.1	0.0
Consideration from exercise of stock options, Shares			100,000
Other share-based benefit transactions		(1.0)	$ 0.0	(0.9)	(0.1)
Other share-based benefit transactions, shares			0
Ending balance at Sep. 30, 2017		480.3	$ 50.5	623.5	624.6	(840.2)	21.9
Ending balance, Shares at Sep. 30, 2017			50,500,000
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			50,500,000
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)
Share-based compensation:
Compensation expense		6.8		6.8
Other share-based benefit transactions		(10.1)	$ 0.4	(10.5)
Other share-based benefit transactions, shares			400,000
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			50,900,000
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			50,500,000
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			50,600,000
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			50,900,000
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)
Share-based compensation:
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
Other share-based benefit transactions		0.3	$ 0.1	0.2
Other share-based benefit transactions, shares			100,000
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			51,000,000
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		(336,829)	(400,000)
Dividends to:
Brink’s common shareholders		$ (7.7)			(7.7)
Noncontrolling interests		(1.9)					(1.9)
Share-based compensation:
Compensation expense		6.3		6.3
Other share-based benefit transactions		0.3	$ 0.0	0.3
Other share-based benefit transactions, shares			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			50,600,000

[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.