Business Realignment and Restructuring (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 2,400	$ 603	$ 3,539
Additional restructuring costs	200
Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	2,978	12,530
Particulate Matter Product Line Strategic Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	3,428
Particulate Matter Product Line Strategic Exit [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	3,428
Particulate Matter Product Line Strategic Exit [Member] \| Control Devices [Member] \| Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Estimated total cost	2,800
Particulate Matter Product Line Strategic Exit [Member] \| Control Devices [Member] \| Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Estimated total cost	6,330
Canton Facility Restructuring Plan [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	2,978	12,530
Employee Termination [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,034	(18)	1,939
Employee Termination [Member] \| Canton Facility Restructuring Plan [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,119	8,088
Excess and Obsolete Inventory [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			823
Intangible Impairment [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			200
Fixed Asset Impairment [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			157
Other Restructuring [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	914	323	264
Other Restructuring [Member] \| Particulate Matter Product Line Strategic Exit [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	102
Other Restructuring [Member] \| Canton Facility Restructuring Plan [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,859	4,442
Contract Termination [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	452	9	156
Selling, General and Administrative Expenses [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,774
Selling, General and Administrative Expenses [Member] \| Particulate Matter Product Line Strategic Exit [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	2,611
Selling, General and Administrative Expenses [Member] \| Canton Facility Restructuring Plan [Member] \| Canton Facility [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		1,526
Selling, General and Administrative Expenses [Member] \| Canton Facility Restructuring Plan [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	551
Cost of Goods Sold [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	147
Cost of Goods Sold [Member] \| Particulate Matter Product Line Strategic Exit [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	817
Cost of Goods Sold [Member] \| Canton Facility Restructuring Plan [Member] \| Canton Facility [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		7,625
Cost of Goods Sold [Member] \| Canton Facility Restructuring Plan [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	1,659
Cost of Goods Sold [Member] \| Excess and Obsolete Inventory [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense			$ 823
Design and Development Expense [Member] \| Electronics [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	479
Design and Development Expense [Member] \| Canton Facility Restructuring Plan [Member] \| Canton Facility [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense		$ 3,379
Design and Development Expense [Member] \| Canton Facility Restructuring Plan [Member] \| Control Devices [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 768