Accumulated other comprehensive income (loss) - Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Pretax, benefit plan adjustments, amounts arising during the current period	$ (1.1)	$ (2.6)	$ (5.7)	$ (4.3)
Income tax, benefit plan adjustments, amounts arising the current period	0.3	0.5	1.5	0.8
Pretax, benefit plan adjustments, amounts reclassified to net income (loss)	14.2	11.2	30.0	23.0
Income tax, benefit plan adjustments, amounts reclassified to net income (loss)	(4.8)	(3.9)	(10.0)	(7.9)
Total benefit plan adjustments, net of tax	8.6	5.2	15.8	11.6
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Pretax, foreign currency translation adjustments, amounts arising during the current period	6.9	8.5	(43.5)	4.3
Income tax, foreign currency translation adjustments, amounts arising during the current period	0.0	0.0	0.0	0.0
Pretax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	(0.2)	0.0	(0.2)
Income tax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	0.0	0.0	0.0
Total foreign currency translation adjustments, net of tax	6.9	8.3	(43.5)	4.1
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Unrealized net gains (losses) on available-for-sale securities	0.0	(0.1)	0.0	(0.2)
Pretax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	0.1	0.0	0.1
Pretax, unrealized gains (losses) on available-for-sale securities, amounts reclassified to net income (loss)	(0.1)	0.0	(0.1)	0.1
Income tax, unrealized gains (losses) on available-for-sale securities, amounts arising during the current period	0.0	0.0	0.0	0.0
Total unrealized gains (losses) on available-for-sale securities, net of tax	(0.1)	0.0	(0.1)	0.0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Pretax, gains (losses) on cash flow hedges, amounts arising during the current period	(0.2)	(1.4)	1.9	(1.7)
Income tax, gains (losses) on cash flow hedges, amounts arising during the current period	0.0	0.0	0.0	0.0
Pretax, gains (losses) on cash flow hedges, amounts reclassified to net income (loss)	0.6	0.8	(1.5)	1.7
Income tax, gains (losses) on cash flow hedges amounts reclassified to net income (loss)	0.0	0.0	0.0	0.0
Total gains (losses) on cash flow hedges, net of tax	0.4	(0.6)	0.4	0.0
Pretax, Other Comprehensive Income (Loss)	5.6	4.4	(47.3)	(1.9)
Income Tax, Other Comprehensive Income (Loss)	0.3	0.6	1.5	0.9
Pretax, Amounts Reclassified to Net Income (Loss), Other Comprehensive Income (Loss)	14.7	11.8	28.4	24.6
Income Tax, Amounts Reclassified to Net Income (Loss), Other Comprehensive Income (Loss)	(4.8)	(3.9)	(10.0)	(7.9)
Other comprehensive income (loss)	15.8	12.9	(27.4)	15.7
Amounts attributable to Brink's
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Pretax, benefit plan adjustments, amounts arising during the current period	(1.1)	(2.6)	(5.7)	(4.3)
Income tax, benefit plan adjustments, amounts arising the current period	0.3	0.5	1.5	0.8
Pretax, benefit plan adjustments, amounts reclassified to net income (loss)	14.1	11.1	29.8	22.8
Income tax, benefit plan adjustments, amounts reclassified to net income (loss)	(4.8)	(3.8)	(10.0)	(7.8)
Total benefit plan adjustments, net of tax	8.5	5.2	15.6	11.5
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Pretax, foreign currency translation adjustments, amounts arising during the current period	6.5	7.4	(42.4)	4.0
Income tax, foreign currency translation adjustments, amounts arising during the current period	0.0	0.0	0.0	0.0
Pretax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	(0.2)	0.0	(0.2)
Income tax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	0.0	0.0	0.0
Total foreign currency translation adjustments, net of tax	6.5	7.2	(42.4)	3.8
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax [Abstract]
Unrealized net gains (losses) on available-for-sale securities		(0.1)	0.0	(0.2)
Pretax, foreign currency translation adjustments, amounts reclassified to net income (loss)		0.1	0.0	0.1
Pretax, unrealized gains (losses) on available-for-sale securities, amounts reclassified to net income (loss)	(0.1)	0.0	(0.1)	0.1
Income tax, unrealized gains (losses) on available-for-sale securities, amounts arising during the current period	0.0	0.0	0.0	0.0
Total unrealized gains (losses) on available-for-sale securities, net of tax	(0.1)	0.0	(0.1)	0.0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Pretax, gains (losses) on cash flow hedges, amounts arising during the current period	(0.2)	(1.4)	1.9	(1.7)
Income tax, gains (losses) on cash flow hedges, amounts arising during the current period	0.0	0.0	0.0	0.0
Pretax, gains (losses) on cash flow hedges, amounts reclassified to net income (loss)	0.6	0.8	(1.5)	1.7
Income tax, gains (losses) on cash flow hedges amounts reclassified to net income (loss)	0.0	0.0	0.0	0.0
Total gains (losses) on cash flow hedges, net of tax	0.4	(0.6)	0.4	0.0
Pretax, Other Comprehensive Income (Loss)	5.2	3.3	(46.2)	(2.2)
Income Tax, Other Comprehensive Income (Loss)	0.3	0.6	1.5	0.9
Pretax, Amounts Reclassified to Net Income (Loss), Other Comprehensive Income (Loss)	14.6	11.7	28.2	24.4
Income Tax, Amounts Reclassified to Net Income (Loss), Other Comprehensive Income (Loss)	(4.8)	(3.8)	(10.0)	(7.8)
Other comprehensive income (loss)	15.3	11.8	(26.5)	15.3
Attributable to Noncontrolling Interests
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax [Abstract]
Pretax, benefit plan adjustments, amounts arising during the current period	0.0	0.0	0.0	0.0
Income tax, benefit plan adjustments, amounts arising the current period	0.0	0.0	0.0	0.0
Pretax, benefit plan adjustments, amounts reclassified to net income (loss)	0.1	0.1	0.2	0.2
Income tax, benefit plan adjustments, amounts reclassified to net income (loss)	0.0	(0.1)	0.0	(0.1)
Total benefit plan adjustments, net of tax	0.1	0.0	0.2	0.1
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Pretax, foreign currency translation adjustments, amounts arising during the current period	0.4	1.1	(1.1)	0.3
Income tax, foreign currency translation adjustments, amounts arising during the current period	0.0	0.0	0.0	0.0
Pretax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	0.0	0.0	0.0
Income tax, foreign currency translation adjustments, amounts reclassified to net income (loss)	0.0	0.0	0.0	0.0
Total foreign currency translation adjustments, net of tax	0.4	1.1	(1.1)	0.3
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax [Abstract]
Pretax, Other Comprehensive Income (Loss)	0.4	1.1	(1.1)	0.3
Income Tax, Other Comprehensive Income (Loss)	0.0	0.0	0.0	0.0
Pretax, Amounts Reclassified to Net Income (Loss), Other Comprehensive Income (Loss)	0.1	0.1	0.2	0.2
Income Tax, Amounts Reclassified to Net Income (Loss), Other Comprehensive Income (Loss)	0.0	(0.1)	0.0	(0.1)
Other comprehensive income (loss)	$ 0.5	$ 1.1	$ (0.9)	$ 0.4