Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 30, 2012	Apr. 01, 2011
Segment Reporting and Geographic Information
Sales to external customers	$ 353,630	$ 374,805
Intersegment sales	1,826	2,099
Operating profit (loss)	9,884	18,077
Assets	796,310	759,843
Advanced Material Technologies [Member]
Segment Reporting and Geographic Information
Sales to external customers	241,806	256,626
Intersegment sales	665	681
Operating profit (loss)	5,285	10,709
Assets	358,933	336,190
Performance Alloys [Member]
Segment Reporting and Geographic Information
Sales to external customers	75,228	84,449
Intersegment sales	697	910
Operating profit (loss)	6,260	8,765
Assets	238,471	245,569
Beryllium and Composites [Member]
Segment Reporting and Geographic Information
Sales to external customers	16,117	13,958
Intersegment sales	200	190
Operating profit (loss)	(1,291)	86
Assets	129,033	122,154
Technical Materials [Member]
Segment Reporting and Geographic Information
Sales to external customers	20,400	19,661
Intersegment sales	264	318
Operating profit (loss)	1,893	2,157
Assets	24,560	25,651
Subtotal [Member]
Segment Reporting and Geographic Information
Sales to external customers	353,551	374,694
Intersegment sales	1,826	2,099
Operating profit (loss)	12,147	21,717
Assets	750,997	729,564
All Other [Member]
Segment Reporting and Geographic Information
Sales to external customers	79	111
Operating profit (loss)	(2,263)	(3,640)
Assets	$ 45,313	$ 30,279