CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Apr. 01, 2012
Operating Activities:
Consolidated net income	$ 19,604	$ 18,608
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, depletion and amortization	11,599	13,026
Payments relating to restructuring activities	0	(620)
Other non-cash items	2,070	1,874
Net changes in operating assets and liabilities	(8,584)	(8,168)
Net cash provided by operating activities	24,689	24,720
Investing Activities:
Purchases of property, plant and equipment	(8,681)	(9,354)
Proceeds from sale of short-term investments	0	1,484
Purchases of short-term investments	(941)	(2,583)
Net cash used in investing activities	(9,622)	(10,453)
Financing Activities:
Net repayment of short-term debt	(81)	(593)
Purchase of common shares for treasury	(7,587)	0
Proceeds from issuance of stock under option plan	2,751	2,084
Cash dividends paid	(1,754)	(887)
Dividends paid to non-controlling interest	(486)	0
Excess tax benefits related to stock incentive programs	184	0
Net cash provided by (used in) financing activities	(6,973)	604
Effect of exchange rate changes on cash and cash equivalents	(7,855)	4,982
Net increase in cash and cash equivalents	239	19,853
Cash and cash equivalents at beginning of period	454,092	395,152
Cash and cash equivalents at end of period	454,331	415,005
Supplemental disclosure of cash flow information:
Interest paid	172	158
Income taxes paid	5,657	10,583
Non-cash financing activities:
Treasury stock purchases settled after period-end	$ 1,860	$ 0