Segment Reporting (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 27, 2020	Mar. 29, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 277,946	$ 301,441
Semiconductor
Disaggregation of Revenue [Line Items]
Net sales	121,736	107,167
Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales	18,354	17,246
Industrial Components
Disaggregation of Revenue [Line Items]
Net sales	34,799	38,508
Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales	20,741	33,438
Energy
Disaggregation of Revenue [Line Items]
Net sales	28,897	33,291
Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales	10,860	17,794
Automotive
Disaggregation of Revenue [Line Items]
Net sales	20,260	22,287
Other End Market
Disaggregation of Revenue [Line Items]
Net sales	22,299	31,710
Performance Alloys and Composites
Disaggregation of Revenue [Line Items]
Net sales	99,067	127,113
Performance Alloys and Composites | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales	906	1,965
Performance Alloys and Composites | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales	14,695	13,555
Performance Alloys and Composites | Industrial Components
Disaggregation of Revenue [Line Items]
Net sales	23,340	26,430
Performance Alloys and Composites | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales	14,206	27,074
Performance Alloys and Composites | Energy
Disaggregation of Revenue [Line Items]
Net sales	5,429	11,094
Performance Alloys and Composites | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales	9,989	17,592
Performance Alloys and Composites | Automotive
Disaggregation of Revenue [Line Items]
Net sales	18,163	20,713
Performance Alloys and Composites | Other End Market
Disaggregation of Revenue [Line Items]
Net sales	12,339	8,690
Advanced Materials
Disaggregation of Revenue [Line Items]
Net sales	160,165	144,025
Advanced Materials | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales	120,819	105,090
Advanced Materials | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales	118	205
Advanced Materials | Industrial Components
Disaggregation of Revenue [Line Items]
Net sales	8,362	7,928
Advanced Materials | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales	1,426	1,493
Advanced Materials | Energy
Disaggregation of Revenue [Line Items]
Net sales	23,468	22,197
Advanced Materials | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales	871	202
Advanced Materials | Automotive
Disaggregation of Revenue [Line Items]
Net sales	2,080	1,353
Advanced Materials | Other End Market
Disaggregation of Revenue [Line Items]
Net sales	3,021	5,557
Precision Coatings
Disaggregation of Revenue [Line Items]
Net sales	18,714	30,303
Precision Coatings | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales	11	112
Precision Coatings | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales	3,541	3,486
Precision Coatings | Industrial Components
Disaggregation of Revenue [Line Items]
Net sales	3,097	4,150
Precision Coatings | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales	5,109	4,871
Precision Coatings | Energy
Disaggregation of Revenue [Line Items]
Net sales	0	0
Precision Coatings | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales	0	0
Precision Coatings | Automotive
Disaggregation of Revenue [Line Items]
Net sales	17	221
Precision Coatings | Other End Market
Disaggregation of Revenue [Line Items]
Net sales	6,939	17,463
Other
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Semiconductor
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Consumer Electronics
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Industrial Components
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Aerospace and Defense
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Energy
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Telecomm and Data Center
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Automotive
Disaggregation of Revenue [Line Items]
Net sales	0	0
Other | Other End Market
Disaggregation of Revenue [Line Items]
Net sales	$ 0	$ 0