Segment Information - Percentage of Total Sales by Product Group (Details) - Sales	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Breathing Apparatus
Revenue from External Customer [Line Items]
Concentration risk percentage	24.00%	27.00%	25.00%	28.00%
Fixed Gas & Flame Detection
Revenue from External Customer [Line Items]
Concentration risk percentage	21.00%	18.00%	20.00%	19.00%
Portable Gas Detection
Revenue from External Customer [Line Items]
Concentration risk percentage	13.00%	14.00%	13.00%	13.00%
Industrial Head Protection
Revenue from External Customer [Line Items]
Concentration risk percentage	12.00%	11.00%	12.00%	10.00%
Fall Protection
Revenue from External Customer [Line Items]
Concentration risk percentage	9.00%	8.00%	9.00%	8.00%
Fire & Rescue Helmets
Revenue from External Customer [Line Items]
Concentration risk percentage	5.00%	5.00%	5.00%	5.00%
Other
Revenue from External Customer [Line Items]
Concentration risk percentage	16.00%	17.00%	16.00%	17.00%