Segment Information - Sales to External Customers and Gross Profit (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jul. 03, 2011	Jul. 01, 2012	Jul. 03, 2011
Segment Reporting Information [Line Items]
Sales to external customers	$ 221,452	$ 211,141	$ 439,007	$ 408,101
Gross profit	104,429	95,695	202,540	181,599
Electronics [Member]
Segment Reporting Information [Line Items]
Sales to external customers	81,504	86,990	159,394	148,338
Gross profit	44,490	45,121	86,219	76,883
Materials Science [Member]
Segment Reporting Information [Line Items]
Sales to external customers	68,476	55,136	141,696	125,795
Gross profit	31,811	24,753	65,139	55,526
Life Sciences [Member]
Segment Reporting Information [Line Items]
Sales to external customers	22,664	26,770	40,898	50,795
Gross profit	10,351	12,766	17,300	22,668
Service and Components [Member]
Segment Reporting Information [Line Items]
Sales to external customers	48,808	42,245	97,019	83,173
Gross profit	$ 17,777	$ 13,055	$ 33,882	$ 26,522