CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 01, 2012	Apr. 03, 2011
Operating Activities:
Consolidated net income	$ 18,608	$ 16,690
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	13,026	14,688
Payments relating to restructuring activities	(620)	(833)
Other non-cash items	1,874	1,653
Net changes in operating assets and liabilities	(8,168)	(13,136)
Net cash provided by operating activities	24,720	19,062
Investing Activities:
Purchases of property, plant and equipment	(9,354)	(8,205)
Proceeds from sale of short-term investments	1,484	2,764
Purchases of short-term investments	(2,583)	(4,336)
Net cash used in investing activities	(10,453)	(9,777)
Financing Activities:
Proceeds from issuance of long-term debt	0	1,596
Net issuance (repayment) of short-term debt	(593)	80
Purchase of common shares for treasury	0	(9,793)
Proceeds from issuance of stock under option plan	2,084	3,902
Cash dividends paid	(887)	(914)
Net cash used in financing activities	604	(5,129)
Effect of exchange rate changes on cash and cash equivalents	4,982	8,821
Net increase in cash and cash equivalents	19,853	12,977
Cash and cash equivalents at beginning of period	395,152	367,827
Cash and cash equivalents at end of period	415,005	380,804
Supplemental disclosure of cash flow information:
Interest paid	158	51
Income taxes paid	$ 10,583	$ 8,752