Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenues	$ 678,595	$ 599,099	$ 575,336
Costs and expenses:
Cost of goods sold	470,365	462,304	470,037
Selling, general and administrative expenses	55,408	51,697	46,392
Environmental charges for Avery Landing	4,978	1,022
Deltic merger-related costs	3,409
Gain on lumber price swap	(1,088)
Loss on sale of central Idaho timber and timberlands		48,522
Total costs and expenses	533,072	563,545	516,429
Operating income	145,523	35,554	58,907
Interest expense, net	(27,049)	(28,941)	(32,761)
Income before income taxes	118,474	6,613	26,146
Income tax (provision) benefit	(32,021)	4,325	5,568
Net income	$ 86,453	$ 10,938	$ 31,714
Net income per share:
Basic (in dollars per share)	$ 2.12	$ 0.27	$ 0.78
Diluted (in dollars per share)	2.10	0.27	0.77
Dividends per share (in dollars per share)	$ 1.525	$ 1.50	$ 1.50
Weighted-average shares outstanding (in thousands)
Basic (in shares)	40,824,420	40,797,806	40,842,126
Diluted (in shares)	41,227,388	41,033,440	40,987,819