Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating activities
Net income	$ 7,914	$ 21,554	$ 64,575
Adjustments to reconcile to net cash provided by operations:
Depreciation, depletion and amortization	76,048	65,826	63,236
Amortization of debt issue costs and original issue discount	1,157	1,153	1,184
Pension expense, net of unfunded benefits paid	4,933	11,180	7,383
Charge for impairment of intangible asset			1,200
Deferred income tax provision (benefit)	19,026	(22,055)	(1,902)
(Gains) losses on dispositions of plant, equipment and timberlands, net	26	216	(21,113)
Share-based compensation	6,214	5,889	7,244
Change in operating assets and liabilities
Accounts receivable	(10,189)	8,372	(13,312)
Inventories	9,198	(10,778)	(8,054)
Prepaid and other current assets	(6,300)	(2,430)	5,506
Accounts payable	13,065	(8,174)	26,042
Accruals and other current liabilities	(17,615)	43,195	(2,186)
Other	785	2,162	3,940
Net cash provided by operating activities	104,262	116,110	133,743
Investing activities
Expenditures for purchases of plant, equipment and timberlands	(132,304)	(160,158)	(99,889)
Proceeds from disposals of plant, equipment and timberlands, net	228	70	24,459
Acquisition, net of cash acquired			(224)
Other investing	(243)	(800)	(1,600)
Net cash used by investing activities	(132,319)	(160,888)	(77,254)
Financing activities
Net borrowings (repayments) under revolving credit facility	109,436	2,891	(22,294)
Payments of borrowing costs		(136)	(1,329)
Proceeds from term loans		19,428	2,873
Repayment of term loans	(9,771)	(8,205)	(5,229)
Payments of dividends	(22,480)	(21,589)	(20,443)
Proceeds from government grants	4,875	5,582	421
Payments related to share-based compensation awards and other	(472)	(990)	(2,015)
Net cash provided (used) by financing activities	81,588	(3,019)	(48,016)
Effect of exchange rate changes on cash	7,244	(2,063)	(3,006)
Net increase (decrease) in cash and cash equivalents	60,775	(49,860)	5,467
Cash and cash equivalents at the beginning of period	55,444	105,304	99,837
Cash and cash equivalents at the end of period	116,219	55,444	105,304
Cash paid for:
Interest, net of amounts capitalized	16,476	14,569	16,256
Income taxes, net	$ 9,336	$ 14,020	$ 15,849