Consolidated Statements of Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenues	$ 190,441	$ 174,027	$ 503,351	$ 443,418
Costs and expenses:
Cost of goods sold	124,971	122,132	349,310	345,324
Selling, general and administrative expenses	14,619	12,901	41,773	38,712
Environmental charges for Avery Landing	4,978		4,978	1,022
Loss (gain) on lumber price swap	2,080		(1,185)
Loss on sale of central Idaho timber and timberlands				48,522
Total costs and expenses	146,648	135,033	394,876	433,580
Operating income	43,793	38,994	108,475	9,838
Interest expense, net	(7,336)	(7,786)	(19,654)	(22,017)
Income (loss) before income taxes	36,457	31,208	88,821	(12,179)
Income tax (provision) benefit	(2,757)	(3,562)	(13,956)	8,744
Net income (loss)	$ 33,700	$ 27,646	$ 74,865	$ (3,435)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.83	$ 0.68	$ 1.83	$ (0.08)
Diluted (in dollars per share)	0.82	0.68	1.82	(0.08)
Dividends per share (in dollars per share)	$ 0.375	$ 0.375	$ 1.125	$ 1.125
Weighted-average shares outstanding (in thousands):
Basic (in shares)	40,829,399	40,739,730	40,814,135	40,807,028
Diluted (in shares)	41,250,457	40,933,351	41,182,795	40,807,028