Summary of Net Sales, Operating Income (Loss), and Total Assets by Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total net sales	$ 199.8	$ 196.1
Total operating income	12.1	10.3
Interest expense	4.5	5.1
Debt settlement charges	8.7	1.6
Other income, net	(0.2)	(0.2)
Income (loss) before income taxes	(0.9)	3.8
Total identifiable assets	601.8		613.2
Environmental Solutions
Segment Reporting Information [Line Items]
Total net sales	111.7	108.0
Total operating income	12.7	12.0
Total identifiable assets	247.5		237.5
Safety And Security Systems
Segment Reporting Information [Line Items]
Total net sales	58.5	56.3
Total operating income	5.5	4.6
Total identifiable assets	204.1		209.5
Fire Rescue
Segment Reporting Information [Line Items]
Total net sales	29.6	31.8
Total operating income	0.7	0.8
Total identifiable assets	120.8		122.5
Corporate and Eliminations
Segment Reporting Information [Line Items]
Total operating income	(6.8)	(7.1)
Total identifiable assets	27.4		41.7
Segment, Continuing Operations
Segment Reporting Information [Line Items]
Total identifiable assets	599.8		611.2
Segment, Discontinued Operations
Segment Reporting Information [Line Items]
Total identifiable assets	$ 2.0		$ 2.0