Condensed Consolidating Financial Statements - Condensed Consolidating Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Assets
Cash and cash equivalents	$ 50,752	$ 105,304	$ 73,665	$ 99,837
Other current assets	478,816	447,063
Plant, equipment and timberlands, net	771,453	698,864
Other assets	253,218	249,185
Total assets	1,554,239	1,500,416
Liabilities and Shareholders' Equity
Current liabilities	316,118	304,320
Long-term debt	367,549	353,296
Deferred income taxes	73,075	76,458
Other long-term liabilities	105,808	103,095
Total liabilities	862,550	837,169
Shareholders' equity	691,689	663,247
Total liabilities and shareholders’ equity	1,554,239	1,500,416
Adjustments/ Eliminations [Member]
Assets
Other current assets	(280,576)	(230,509)
Investments in subsidiaries	(1,347,241)	(1,244,566)
Total assets	(1,627,817)	(1,475,075)
Liabilities and Shareholders' Equity
Current liabilities	(280,576)	(230,523)
Total liabilities	(280,576)	(230,523)
Shareholders' equity	(1,347,241)	(1,244,552)
Total liabilities and shareholders’ equity	(1,627,817)	(1,475,075)
Parent Company [Member]
Assets
Cash and cash equivalents	3,658	59,130	28,626	42,208
Other current assets	222,853	199,690
Plant, equipment and timberlands, net	351,301	286,334
Investments in subsidiaries	798,376	737,450
Other assets	115,900	106,586
Total assets	1,492,088	1,389,190
Liabilities and Shareholders' Equity
Current liabilities	415,957	363,037
Long-term debt	269,535	247,075
Deferred income taxes	26,048	28,561
Other long-term liabilities	88,859	87,270
Total liabilities	800,399	725,943
Shareholders' equity	691,689	663,247
Total liabilities and shareholders’ equity	1,492,088	1,389,190
Guarantors [Member]
Assets
Cash and cash equivalents	418	465	297	509
Other current assets	265,889	238,515
Plant, equipment and timberlands, net	20,918	1,114
Investments in subsidiaries	548,865	507,116
Total assets	836,090	747,210
Liabilities and Shareholders' Equity
Current liabilities	36,689	9,725
Long-term debt	1,000
Deferred income taxes	(288)	(79)
Other long-term liabilities	313
Total liabilities	37,714	9,646
Shareholders' equity	798,376	737,564
Total liabilities and shareholders’ equity	836,090	747,210
Non Guarantors [Member]
Assets
Cash and cash equivalents	46,676	45,709	$ 44,742	$ 57,120
Other current assets	270,650	239,367
Plant, equipment and timberlands, net	399,234	411,416
Other assets	137,318	142,599
Total assets	853,878	839,091
Liabilities and Shareholders' Equity
Current liabilities	144,048	162,081
Long-term debt	97,014	106,221
Deferred income taxes	47,315	47,976
Other long-term liabilities	16,636	15,825
Total liabilities	305,013	332,103
Shareholders' equity	548,865	506,988
Total liabilities and shareholders’ equity	$ 853,878	$ 839,091