Revenue (Disaggregation of Revenue by Contract Type) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Total Timber Sales	$ 815,044	$ 818,521	$ 814,877
Operating Segments | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	169,178	143,704	150,434
Operating Segments | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	109,555	91,608	77,522
Operating Segments | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	249,014	223,299	176,041
Operating Segments | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	148,722	152,584	109,682
Stumpage Pay-as-Cut
Disaggregation of Revenue [Line Items]
Total Timber Sales	72,385	71,120	73,673
Stumpage Pay-as-Cut | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	72,385	71,120	73,673
Stumpage Pay-as-Cut | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Stumpage Pay-as-Cut | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Stumpage Pay-as-Cut | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Stumpage Lump Sum
Disaggregation of Revenue [Line Items]
Total Timber Sales	16,842	19,721	7,229
Stumpage Lump Sum | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	4,988	9,093	4,341
Stumpage Lump Sum | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	11,854	10,628	2,121
Stumpage Lump Sum | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	767
Stumpage Lump Sum | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Stumpage Agreed Volume
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	1,234	2,492
Stumpage Agreed Volume | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Stumpage Agreed Volume | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	1,234	2,492
Stumpage Agreed Volume | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Stumpage Agreed Volume | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Total Stumpage
Disaggregation of Revenue [Line Items]
Total Timber Sales	89,227	92,075	83,394
Total Stumpage | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	77,373	80,213	78,014
Total Stumpage | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	11,854	11,862	4,613
Total Stumpage | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	767
Total Stumpage | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Total Delivered
Disaggregation of Revenue [Line Items]
Total Timber Sales	551,120	492,944	403,700
Total Delivered | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	66,490	42,426	54,840
Total Delivered | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	94,617	76,857	70,574
Total Delivered | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	241,943	222,455	169,973
Total Delivered | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	148,070	151,206	108,313
Total Delivered | Domestic
Disaggregation of Revenue [Line Items]
Total Timber Sales	252,320	209,548	200,465
Total Delivered | Domestic | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	60,931	42,426	54,840
Total Delivered | Domestic | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	94,617	76,857	70,574
Total Delivered | Domestic | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	90,631	84,221	71,294
Total Delivered | Domestic | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	6,141	6,044	3,757
Total Delivered | Export
Disaggregation of Revenue [Line Items]
Total Timber Sales	298,800	283,396	203,235
Total Delivered | Export | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	5,559	0	0
Total Delivered | Export | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	0	0	0
Total Delivered | Export | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	151,312	138,234	98,679
Total Delivered | Export | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	141,929	145,162	104,556
Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	640,347	585,019	487,094
Timber | Operating Segments | Southern Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	143,863	122,639	132,854
Timber | Operating Segments | Pacific Northwest Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	106,471	88,719	75,187
Timber | Operating Segments | New Zealand Timber
Disaggregation of Revenue [Line Items]
Total Timber Sales	241,943	222,455	170,740
Timber | Operating Segments | Trading
Disaggregation of Revenue [Line Items]
Total Timber Sales	$ 148,070	$ 151,206	$ 108,313