Acquisitions and Dispositions - Pro Forma (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Acquisition [Line Items]
Actual revenue results included in consolidation	$ 46.7	$ 6.4	$ 100.8	$ 7.0
Actual net income results included in consolidation	0.9	0.5	4.8	0.6
Revenues	849.7	805.9	1,728.8	1,594.3
Reported net income (loss) attributable to Brink's	(107.9)	14.2	(85.6)	48.9
Pro forma revenue results	849.7	851.9	1,728.8	1,693.2
Pro forma net income results	(107.9)	18.8	(85.6)	56.6
Transaction costs	2.1	0.7	2.1	0.7
Maco
Business Acquisition [Line Items]
Actual revenue results included in consolidation	20.3	0.0	44.6	0.0
Actual net income results included in consolidation	0.7	0.0	4.1	0.0
Pro forma revenue results	0.0	26.9	0.0	51.8
Pro forma net income results	0.0	2.9	0.0	5.5
Other Acquisitions
Business Acquisition [Line Items]
Actual revenue results included in consolidation	26.4	6.4	56.2	7.0
Actual net income results included in consolidation	0.2	0.5	0.7	0.6
Pro forma revenue results	0.0	19.1	0.0	47.1
Pro forma net income results	$ 0.0	$ 1.7	$ 0.0	$ 2.2