Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 23.6	$ 44.8	$ (28.2)
Benefit plan adjustments:
Benefit plan actuarial gains (losses)	(43.6)	12.6	4.4
Benefit plan prior service costs	(0.9)	(1.6)	(3.6)
Deferred profit sharing	0.0	(0.3)	0.0
Total benefit plan adjustments	(44.5)	10.7	0.8
Foreign currency translation adjustments	23.6	(26.3)	(104.1)
Unrealized net gains (losses) on available-for-sale securities	0.2	(0.1)	(0.5)
Gains (loss) on cash flow hedges	0.1	0.8	(0.3)
Other comprehensive loss before tax	(20.6)	(14.9)	(104.1)
Provision (benefit) for income taxes	(1.8)	0.9	(0.7)
Other comprehensive loss	(18.8)	(15.8)	(103.4)
Comprehensive income (loss)	4.8	29.0	(131.6)
Less comprehensive income (loss) attributable to noncontrolling interests	7.7	9.6	(20.1)
Comprehensive income (loss) attributable to Brink’s	$ (2.9)	$ 19.4	$ (111.5)