Consolidated Statements of Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenues	$ 163,229	$ 141,495	$ 312,910	$ 269,391
Costs and expenses:
Cost of goods sold	111,556	113,377	224,339	223,192
Selling, general and administrative expenses	14,165	13,824	27,154	26,833
Gain on lumber price swap	(3,265)		(3,265)
Loss on sale of central Idaho timber and timberlands		48,522		48,522
Total costs and expenses	122,456	175,723	248,228	298,547
Operating income (loss)	40,773	(34,228)	64,682	(29,156)
Interest expense, net	(7,348)	(8,206)	(12,318)	(14,231)
Income (loss) before income taxes	33,425	(42,434)	52,364	(43,387)
Income tax (provision) benefit	(9,181)	11,196	(11,199)	12,306
Net income (loss)	$ 24,244	$ (31,238)	$ 41,165	$ (31,081)
Net income (loss) per share:
Basic (in dollars per share)	$ 0.59	$ (0.77)	$ 1.01	$ (0.76)
Diluted (in dollars per share)	0.59	(0.77)	1.00	(0.76)
Distributions per share (in dollars per share)	$ 0.375	$ 0.375	$ 0.75	$ 0.75
Weighted-average shares outstanding (in thousands):
Basic (in shares)	40,822,726	40,784,129	40,802,057	40,836,503
Diluted (in shares)	41,218,969	40,784,129	41,143,695	40,836,503