Changes in Each Component of Accumulated Other Comprehensive Loss (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income, Pension Benefit Plan Costs	$ (1.9)	[1]
Amounts reclassified from accumulated other comprehensive income, Foreign Currency	(0.3)	[1]
Federal Signal Technologies
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from accumulated other comprehensive income, Pension Benefit Plan Costs	2.0
Amounts reclassified from accumulated other comprehensive income, Pension Benefit Plan Costs, tax benefit	0.1
Amounts reclassified from accumulated other comprehensive income, Foreign Currency	$ 0.3

[1] Represents $2.0 million of costs included in net postretirement pension expense, net of income tax benefit of $0.1 million, and $0.3 million of foreign currency effects related to the FSTech disposal included in gain from discontinued operations and disposal.