Other Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016
Sale Leaseback Transaction [Line Items]
Workers’ compensation and other claims	$ 57.7		$ 56.5
Non-recourse financing liability(a)	0.0		12.6
Post-employment benefits	10.9		11.5
Asset retirement and remediation obligations	12.6		14.3
Acquisition-related obligations	17.8		0.0
Noncurrent tax liabilities	9.1		5.3
Other	42.1		35.9
Other liabilities	$ 150.2		$ 136.1
Brink's Mexico | Mexico City
Sale Leaseback Transaction [Line Items]
Lease term (in years)	2 years	2 years