REVENUE (Disaggregation of Revenue by Contract Type) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total Timber Sales	$ 200,616	$ 184,171	$ 649,173	$ 579,087
Stumpage Pay-as-Cut
Disaggregation of Revenue [Line Items]
Total Timber Sales	16,984	18,607	59,348	56,956
Stumpage Lump Sum
Disaggregation of Revenue [Line Items]
Total Timber Sales	2,427	5,941	14,212	13,571
Stumpage Agreed Volume
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	1,234
Total Stumpage
Disaggregation of Revenue [Line Items]
Total Timber Sales	19,411	24,548	73,560	71,761
Total Delivered
Disaggregation of Revenue [Line Items]
Total Timber Sales	137,196	136,161	424,886	365,957
Total Delivered | Domestic
Disaggregation of Revenue [Line Items]
Total Timber Sales	67,352	52,243	196,203	154,530
Total Delivered | Export
Disaggregation of Revenue [Line Items]
Total Timber Sales	69,844	83,918	228,683	211,427
Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	156,607	160,709	498,446	437,718
Southern Timber | Stumpage Pay-as-Cut
Disaggregation of Revenue [Line Items]
Total Timber Sales	16,984	18,607	59,348	56,956
Southern Timber | Stumpage Lump Sum
Disaggregation of Revenue [Line Items]
Total Timber Sales	284	1,954	2,358	6,997
Southern Timber | Stumpage Agreed Volume
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
Southern Timber | Total Stumpage
Disaggregation of Revenue [Line Items]
Total Timber Sales	17,268	20,561	61,706	63,953
Southern Timber | Total Delivered
Disaggregation of Revenue [Line Items]
Total Timber Sales	17,535	11,336	48,526	31,437
Southern Timber | Total Delivered | Domestic
Disaggregation of Revenue [Line Items]
Total Timber Sales	15,856	11,336	44,399	31,437
Southern Timber | Total Delivered | Export
Disaggregation of Revenue [Line Items]
Total Timber Sales	1,679	0	4,127	0
Pacific Northwest Timber | Stumpage Pay-as-Cut
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
Pacific Northwest Timber | Stumpage Lump Sum
Disaggregation of Revenue [Line Items]
Total Timber Sales	2,143	3,987	11,854	6,574
Pacific Northwest Timber | Stumpage Agreed Volume
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	1,234
Pacific Northwest Timber | Total Stumpage
Disaggregation of Revenue [Line Items]
Total Timber Sales	2,143	3,987	11,854	7,808
Pacific Northwest Timber | Total Delivered
Disaggregation of Revenue [Line Items]
Total Timber Sales	24,912	14,659	76,966	55,078
Pacific Northwest Timber | Total Delivered | Domestic
Disaggregation of Revenue [Line Items]
Total Timber Sales	24,912	14,659	76,966	55,078
Pacific Northwest Timber | Total Delivered | Export
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
New Zealand Timber | Stumpage Pay-as-Cut
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
New Zealand Timber | Stumpage Lump Sum
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
New Zealand Timber | Stumpage Agreed Volume
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
New Zealand Timber | Total Stumpage
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
New Zealand Timber | Total Delivered
Disaggregation of Revenue [Line Items]
Total Timber Sales	63,941	69,913	183,537	163,506
New Zealand Timber | Total Delivered | Domestic
Disaggregation of Revenue [Line Items]
Total Timber Sales	24,771	24,440	70,521	63,883
New Zealand Timber | Total Delivered | Export
Disaggregation of Revenue [Line Items]
Total Timber Sales	39,170	45,473	113,016	99,623
Trading | Stumpage Pay-as-Cut
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
Trading | Stumpage Lump Sum
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
Trading | Stumpage Agreed Volume
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
Trading | Total Stumpage
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0	0
Trading | Total Delivered
Disaggregation of Revenue [Line Items]
Total Timber Sales	30,808	40,253	115,857	115,936
Trading | Total Delivered | Domestic
Disaggregation of Revenue [Line Items]
Total Timber Sales	1,813	1,808	4,317	4,132
Trading | Total Delivered | Export
Disaggregation of Revenue [Line Items]
Total Timber Sales	$ 28,995	$ 38,445	$ 111,540	$ 111,804