Business Segments, Geographical and Customer Information (Other Information by Segment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and amortization	$ 22,235	$ 21,137	$ 21,586
Capital expenditures	9,588	8,395	9,047
Assets	387,101	503,597
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and amortization	21,615	20,684	21,229
Assets	317,923	485,771
Operating Segments | Industrial
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and amortization	12,952	12,196	12,198
Capital expenditures	6,650	4,365	5,247
Assets	235,726	230,185
Operating Segments | Engineered Components Segment
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and amortization	8,663	8,488	8,435
Capital expenditures	2,448	3,207	2,709
Assets	82,197	90,175
Operating Segments | Fiber Solutions
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and amortization	0	0	596
Capital expenditures	0	0	534
Operating Segments | Acoustics
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	0	165,411
Corporate
Segment Reporting, Asset Reconciling Item [Line Items]
Depreciation and amortization	620	453	357
Capital expenditures	490	823	$ 557
Corporate and eliminations
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 69,178	$ 17,826