CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Activities
Consolidated net income (loss)	$ 70,254	$ 69,886	$ (20,904)
Income (loss) from discontinued operations, net of tax	0	0	(3,151)
Income (loss) from continuing operations	70,254	69,886	(17,753)
Adjustments to reconcile income (loss) from continuing operations to net cash provided by operating activities:
Depreciation, depletion and amortization	58,223	63,981	72,401
Impairment of assets	0	0	39,831
Pension settlement loss and amortization	0	0	18,833
Loss on disposal of property, plant and equipment	288	941	793
Deferred income taxes	1,250	1,772	(23,989)
Provision for bad debts	878	49	1,271
Stock-based compensation	7,237	5,860	5,780
Other non-cash items	41	189	0
Changes in operating assets and liabilities
Accounts receivable	(14,186)	(7,577)	(7,680)
Inventories	(7,340)	(3,713)	58,835
Prepaid expenses and other current assets	(5,787)	3,164	8,558
Pension plan funding	(6,650)	(8,466)	(8,642)
Accounts payable	24,824	6,351	5,455
Restructuring liabilities	(2,550)	(4,741)	1,442
Income taxes payable	(712)	6,829	2,090
Tax benefits related to stock incentive programs	166	136	42
Other	7,723	7,758	(778)
Net cash provided by continuing operations	133,659	142,419	156,489
Net cash provided by discontinued operations	0	0	4,340
Net cash provided by operations	133,659	142,419	160,829
Investing Activities
Purchases of property, plant and equipment	(52,060)	(34,518)	(26,591)
Purchases of short-term investments	(12,423)	(10,738)	(7,144)
Proceeds from sales of short-term investments	9,380	4,125	10,052
Proceeds from disposal of property, plant and equipment	78	39	838
Net cash used in investing activities - continuing operations	(55,025)	(41,092)	(22,845)
Net cash provided by investing activities - discontinued operations	0	0	4,428
Net cash used in investing activities	(55,025)	(41,092)	(18,417)
Financing Activities
Repayment of long-term debt	(275)	(4,600)	(4,000)
Proceeds from issuance of long term debt	1,596	0	0
Net issuance (repayment) of short-term debt	2,030	(1,331)	(8,249)
Purchase of common shares for treasury	(48,004)	(27,922)	0
Cash dividends paid	(3,601)	(3,720)	(3,743)
Proceeds from issuance of stock under option plan	5,912	1,086	172
Excess tax benefits related to stock incentive programs	6	53	12
Net cash used in financing activities	(42,336)	(36,434)	(15,808)
Effect of exchange rate changes on cash and cash equivalents	(8,973)	(8,012)	2,466
Net increase in cash and cash equivalents	27,325	56,881	129,070
Cash and cash equivalents at beginning of period	367,827	310,946	181,876
Cash and cash equivalents at end of period	395,152	367,827	310,946
Non-cash Investing and Financing Activities:
Treasury stock purchases settled after year-end	$ 0	$ 2,069	$ 0