Condensed Consolidating Financial Statements - Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided (used) 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	(243)	(800)	(1,600)
Net cash used by investing activities	(132,319)	(160,888)	(77,254)
Financing activities
Net long-term borrowings	99,665	14,114	(24,650)
Payments of borrowing costs		(136)	(1,329)
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 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
Adjustments/ Eliminations [Member]
Investing activities
Repayments from intercompany loans	(12,000)	(15,601)	(57,855)
Advances of intercompany loans	14,400	18,330	49,230
Intercompany capital (contributed) returned	14,400	17,500	(9,800)
Net cash used by investing activities	16,800	20,229	(18,425)
Financing activities
Repayments of intercompany loans	12,000	15,601	57,855
Borrowings of intercompany loans	(14,400)	(18,330)	(49,230)
Intercompany capital (returned) received	(14,400)	(17,500)	9,800
Net cash provided (used) by financing activities	(16,800)	(20,229)	18,425
Parent Company [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided (used) by Operating activities	(4,259)	33,109	34,391
Investing activities
Expenditures for purchases of plant, equipment and timberlands	(65,822)	(104,595)	(65,265)
Proceeds from disposals of plant, equipment and timberlands, net	11	41	22,741
Intercompany capital (contributed) returned	(14,000)	(17,000)	10,100
Other	(243)	(800)	(1,600)
Net cash used by investing activities	(80,054)	(122,354)	(34,024)
Financing activities
Net long-term borrowings	84,200	36,000
Payments of borrowing costs		(136)	(1,329)
Payments of dividends	(22,480)	(21,589)	(20,443)
Repayments of intercompany loans			(9,158)
Borrowings of intercompany loans	14,400	18,330	49,230
Proceeds from government grants	4,875	3,582	421
Payments related to share-based compensation awards and other	(472)	(990)	(2,166)
Net cash provided (used) by financing activities	80,523	35,197	16,555
Net increase (decrease) in cash and cash equivalents	(3,790)	(54,048)	16,922
Cash and cash equivalents at the beginning of period	5,082	59,130	42,208
Cash and cash equivalents at the end of period	1,292	5,082	59,130
Guarantors [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided (used) by Operating activities	(3,506)	1,275	627
Investing activities
Expenditures for purchases of plant, equipment and timberlands	(45,644)	(30,682)	(109)
Proceeds from disposals of plant, equipment and timberlands, net	209		1,213
Repayments from intercompany loans	12,000	15,601	57,855
Advances of intercompany loans	(14,400)	(18,330)	(49,230)
Intercompany capital (contributed) returned	(400)	(500)	(300)
Net cash used by investing activities	(48,235)	(33,911)	9,429
Financing activities
Net long-term borrowings	37,000	14,000
Intercompany capital (returned) received	14,000	17,000	(10,100)
Payment of intercompany dividend		632
Proceeds from government grants		2,000
Net cash provided (used) by financing activities	51,000	33,632	(10,100)
Net increase (decrease) in cash and cash equivalents	(741)	996	(44)
Cash and cash equivalents at the beginning of period	1,461	465	509
Cash and cash equivalents at the end of period	720	1,461	465
Non Guarantors [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided (used) by Operating activities	112,027	81,726	98,725
Investing activities
Expenditures for purchases of plant, equipment and timberlands	(20,838)	(24,881)	(34,515)
Proceeds from disposals of plant, equipment and timberlands, net	8	29	505
Acquisition, net of cash acquired			(224)
Net cash used by investing activities	(20,830)	(24,852)	(34,234)
Financing activities
Net long-term borrowings	(21,535)	(35,886)	(24,650)
Repayments of intercompany loans	(12,000)	(15,601)	(48,697)
Intercompany capital (returned) received	400	500	300
Payment of intercompany dividend		(632)
Payments related to share-based compensation awards and other			151
Net cash provided (used) by financing activities	(33,135)	(51,619)	(72,896)
Effect of exchange rate on cash	7,244	(2,063)	(3,006)
Net increase (decrease) in cash and cash equivalents	65,306	3,192	(11,411)
Cash and cash equivalents at the beginning of period	48,901	45,709	57,120
Cash and cash equivalents at the end of period	$ 114,207	$ 48,901	$ 45,709