Segment Information (Income by Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net sales	$ 239,798	$ 214,611
Operating income	32,800	31,044
Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	80,470	73,455
Operating income	13,064	7,903
Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	92,762	78,083
Operating income	13,431	14,159
Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	59,814	57,714
Operating income	4,267	7,021
Other
Segment Reporting Information [Line Items]
Net sales	6,752	5,359
Operating income	2,038	1,961
Recognized over time
Segment Reporting Information [Line Items]
Net sales	67,212	63,087
Recognized over time | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	0	0
Recognized over time | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	3,006	1,039
Recognized over time | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	59,602	57,400
Recognized over time | Other
Segment Reporting Information [Line Items]
Net sales	4,604	4,648
Recognized at a point in time
Segment Reporting Information [Line Items]
Net sales	172,586	151,524
Recognized at a point in time | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	80,470	73,455
Recognized at a point in time | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	89,756	77,044
Recognized at a point in time | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	212	314
Recognized at a point in time | Other
Segment Reporting Information [Line Items]
Net sales	2,148	711
United States
Segment Reporting Information [Line Items]
Net sales	65,303	59,805
United States | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	13,071	12,278
United States | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	43,465	37,692
United States | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	7,477	8,578
United States | Other
Segment Reporting Information [Line Items]
Net sales	1,290	1,257
Other Americas
Segment Reporting Information [Line Items]
Net sales	3,046	2,815
Other Americas | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	752	826
Other Americas | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	2,083	1,801
Other Americas | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	20	358
Other Americas | Other
Segment Reporting Information [Line Items]
Net sales	191	(170)
Total Americas
Segment Reporting Information [Line Items]
Net sales	68,349	62,620
Total Americas | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	13,823	13,104
Total Americas | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	45,548	39,493
Total Americas | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	7,497	8,936
Total Americas | Other
Segment Reporting Information [Line Items]
Net sales	1,481	1,087
China
Segment Reporting Information [Line Items]
Net sales	78,485	65,040
China | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	42,489	33,507
China | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	22,419	20,794
China | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	11,064	9,422
China | Other
Segment Reporting Information [Line Items]
Net sales	2,513	1,317
Other APAC
Segment Reporting Information [Line Items]
Net sales	34,776	31,742
Other APAC | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	14,141	15,338
Other APAC | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	14,488	9,160
Other APAC | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	5,338	6,451
Other APAC | Other
Segment Reporting Information [Line Items]
Net sales	809	793
Total APAC
Segment Reporting Information [Line Items]
Net sales	113,261	96,782
Total APAC | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	56,630	48,845
Total APAC | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	36,907	29,954
Total APAC | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	16,402	15,873
Total APAC | Other
Segment Reporting Information [Line Items]
Net sales	3,322	2,110
Germany
Segment Reporting Information [Line Items]
Net sales	30,001	23,871
Germany | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	4,472	6,250
Germany | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	3,436	2,742
Germany | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	21,947	14,710
Germany | Other
Segment Reporting Information [Line Items]
Net sales	146	169
Other EMEA
Segment Reporting Information [Line Items]
Net sales	28,187	31,338
Other EMEA | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	5,545	5,256
Other EMEA | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	6,871	5,894
Other EMEA | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	13,968	18,195
Other EMEA | Other
Segment Reporting Information [Line Items]
Net sales	1,803	1,993
Total EMEA
Segment Reporting Information [Line Items]
Net sales	58,188	55,209
Total EMEA | Advanced Connectivity Solutions
Segment Reporting Information [Line Items]
Net sales	10,017	11,506
Total EMEA | Elastomeric Material Solutions
Segment Reporting Information [Line Items]
Net sales	10,307	8,636
Total EMEA | Power Electronics Solutions
Segment Reporting Information [Line Items]
Net sales	35,915	32,905
Total EMEA | Other
Segment Reporting Information [Line Items]
Net sales	$ 1,949	$ 2,162