Selected Quarterly Financial Data (unaudited) (Details) - USD ($)	3 Months Ended								9 Months Ended	12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Quarterly Financial Data [Abstract]
Revenues	$ 903,200,000	$ 849,500,000	$ 805,900,000	$ 788,400,000	$ 803,500,000	$ 755,800,000	$ 739,500,000	$ 721,800,000		$ 3,347,000,000		$ 3,020,600,000		$ 3,061,400,000
Operating Profit	88,300,000	66,400,000	48,300,000	70,900,000	69,100,000	59,700,000	32,200,000	23,500,000		273,900,000		184,500,000		96,400,000
Amounts attributable to Brink’s:
Continuing operations	(52,000,000)	19,900,000	14,300,000	34,700,000	14,500,000	24,500,000	300,000	(3,100,000)		16,900,000		36,200,000		(9,100,000)
Discontinued operations	(100,000)	0	(100,000)	0	(1,700,000)	0	0	0		(200,000)		(1,700,000)		(2,800,000)
Net income (loss) attributable to Brink’s	(52,100,000)	19,900,000	14,200,000	34,700,000	12,800,000	24,500,000	300,000	(3,100,000)		16,700,000		34,500,000		(11,900,000)
Depreciation and amortization	40,200,000	37,900,000	34,600,000	33,900,000	34,100,000	32,400,000	32,900,000	32,200,000		146,600,000		131,600,000		139,900,000
Capital expenditures	$ 57,100,000	$ 46,300,000	$ 43,300,000	$ 27,800,000	$ 39,800,000	$ 27,400,000	$ 24,200,000	$ 20,800,000		$ 174,500,000		$ 112,200,000		$ 101,100,000
Basic
Continuing operations (in dollars per share)	$ (1.02)	$ 0.39	$ 0.28	$ 0.69	$ 0.29	$ 0.49	$ 0.01	$ (0.06)		$ 0.33	[1]	$ 0.72	[1]	$ (0.19)	[1]
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00	(0.03)	0.00	0.00	0.00		(0.01)	[1]	(0.03)	[1]	(0.06)	[1]
Net income (loss) (in dollars per share)	(1.03)	0.39	0.28	0.69	0.25	0.49	0.01	(0.06)		0.33	[1]	0.69	[1]	(0.24)	[1]
Diluted
Continuing operations (in dollars per share)	(1.02)	0.38	0.28	0.67	0.28	0.48	0.01	(0.06)		0.33	[1]	0.72	[1]	(0.19)	[1]
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.00	(0.03)	0.00	0.00	0.00		(0.01)	[1]	(0.03)	[1]	(0.06)	[1]
Net income (loss) (in dollars per share)	$ (1.03)	$ 0.38	$ 0.28	$ 0.67	$ 0.25	$ 0.48	$ 0.01	$ (0.06)		$ 0.32	[1]	$ 0.68	[1]	$ (0.24)	[1]
Effect of Fourth Quarter Events [Line Items]
Prepayment penalties										$ 8,300,000		$ 0		$ 0
Loss Due to Gold Theft	$ 11,100,000
Gain on sale of property										9,200,000		(1,300,000)		900,000
Severance costs					$ 7,200,000
Tax Reform Act Tax Expense Charge	92,000,000
Valuation allowances										1,800,000		(2,600,000)		(1,500,000)
Reorganization and Restructuring 2016
Effect of Fourth Quarter Events [Line Items]
Restructuring charge										(17,300,000)		(18,100,000)
Venezuela
Quarterly Financial Data [Abstract]
Revenues										154,100,000		109,400,000		84,500,000
Mexico
Quarterly Financial Data [Abstract]
Revenues										327,200,000		296,300,000		333,700,000
Effect of Fourth Quarter Events [Line Items]
Gain on sale of property	$ 7,800,000									8,400,000
Ireland
Quarterly Financial Data [Abstract]
Revenues														20,000,000
Effect of Fourth Quarter Events [Line Items]
Severance costs								$ 4,200,000
Exit costs							$ 4,500,000	1,700,000
U.S.
Quarterly Financial Data [Abstract]
Revenues										775,800,000		763,800,000		$ 736,500,000
Effect of Fourth Quarter Events [Line Items]
Valuation allowances					14,700,000
Venezuelan bolívar fuerte | Venezuela
Effect of Fourth Quarter Events [Line Items]
Currency remeasurement				$ 8,100,000				2,800,000
Executive Leadership and Board of Directors Restructuring | Ireland
Effect of Fourth Quarter Events [Line Items]
Restructuring charge								$ (3,200,000)
Asset related adjustments
Effect of Fourth Quarter Events [Line Items]
Restructuring charge					(16,300,000)
Asset related adjustments | Ireland
Effect of Fourth Quarter Events [Line Items]
Restructuring charge							$ (2,000,000)
Lease Terminations
Effect of Fourth Quarter Events [Line Items]
Restructuring charge					(700,000)
Lease Terminations | Reorganization and Restructuring 2016
Effect of Fourth Quarter Events [Line Items]
Restructuring charge										(600,000)		(700,000)
Benefit Program Termination | Reorganization and Restructuring 2016
Effect of Fourth Quarter Events [Line Items]
Restructuring charge					$ 6,100,000					$ (2,200,000)		$ 6,100,000
Private Placement Notes
Effect of Fourth Quarter Events [Line Items]
Prepayment penalties		$ 6,500,000							$ 7,000,000

[1] Amounts may not add due to rounding.