Condensed Consolidating Financial Statements - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 117,277	$ 116,219	$ 57,227	$ 55,444
Other current assets	491,423	468,752
Plant, equipment and timberlands, net	870,734	865,743
Other assets	285,178	280,081
Total assets	1,764,612	1,730,795
Liabilities and Shareholders' Equity
Current liabilities	338,696	347,176
Long-term debt	494,131	470,098
Deferred income taxes	85,025	83,571
Other long-term liabilities	122,768	121,022
Total liabilities	1,040,620	1,021,867
Shareholders’ equity	723,992	708,928
Total liabilities and shareholders’ equity	1,764,612	1,730,795
Adjustments/ Eliminations [Member]
Assets
Other current assets	(293,035)	(277,989)
Investments in subsidiaries	(1,509,573)	(1,483,023)
Total assets	(1,802,608)	(1,761,012)
Liabilities and Shareholders' Equity
Current liabilities	(293,035)	(277,989)
Total liabilities	(293,035)	(277,989)
Shareholders’ equity	(1,509,573)	(1,483,023)
Total liabilities and shareholders’ equity	(1,802,608)	(1,761,012)
Parent Company [Member]
Assets
Cash and cash equivalents	1,022	1,292	5,220	5,082
Other current assets	250,524	249,293
Plant, equipment and timberlands, net	370,669	375,231
Investments in subsidiaries	842,154	829,895
Other assets	142,088	139,552
Total assets	1,606,457	1,595,263
Liabilities and Shareholders' Equity
Current liabilities	398,152	402,787
Long-term debt	371,036	368,496
Deferred income taxes	12,049	14,081
Other long-term liabilities	101,228	100,971
Total liabilities	882,465	886,335
Shareholders’ equity	723,992	708,928
Total liabilities and shareholders’ equity	1,606,457	1,595,263
Guarantors [Member]
Assets
Cash and cash equivalents	1,266	720	2,653	1,461
Other current assets	237,841	217,822
Plant, equipment and timberlands, net	87,000	80,992
Investments in subsidiaries	667,419	653,128
Total assets	993,526	952,662
Liabilities and Shareholders' Equity
Current liabilities	67,660	54,640
Long-term debt	65,000	51,000
Deferred income taxes	18,209	16,814
Other long-term liabilities	503	313
Total liabilities	151,372	122,767
Shareholders’ equity	842,154	829,895
Total liabilities and shareholders’ equity	993,526	952,662
Non Guarantors [Member]
Assets
Cash and cash equivalents	114,989	114,207	$ 49,354	$ 48,901
Other current assets	296,093	279,626
Plant, equipment and timberlands, net	413,065	409,520
Other assets	143,090	140,529
Total assets	967,237	943,882
Liabilities and Shareholders' Equity
Current liabilities	165,919	167,738
Long-term debt	58,095	50,602
Deferred income taxes	54,767	52,676
Other long-term liabilities	21,037	19,738
Total liabilities	299,818	290,754
Shareholders’ equity	667,419	653,128
Total liabilities and shareholders’ equity	$ 967,237	$ 943,882