Revenue Recognition (Summary of Revenues by Major Product) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation Of Revenue [Line Items]
Revenues		$ 217,250	$ 289,199	$ 268,233	$ 199,897	$ 175,244	$ 190,441	$ 163,229	$ 149,681	$ 974,579	$ 678,595	$ 599,099
Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues										1,090,447	750,011	656,193
Intersegment Eliminations [Member]
Disaggregation Of Revenue [Line Items]
Revenues	[1]									(115,868)	(71,416)	(57,094)
Resource [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues										354,950	278,199	256,163
Resource [Member] | Operating Segments [Member] | Northern Region [Member]
Disaggregation Of Revenue [Line Items]
Revenues										213,950	197,867	173,202
Resource [Member] | Operating Segments [Member] | Northern Region [Member] | Sawlogs [Member]
Disaggregation Of Revenue [Line Items]
Revenues										205,977	190,693	163,373
Resource [Member] | Operating Segments [Member] | Northern Region [Member] | Pulpwood [Member]
Disaggregation Of Revenue [Line Items]
Revenues										5,996	5,634	8,106
Resource [Member] | Operating Segments [Member] | Northern Region [Member] | Stumpage [Member]
Disaggregation Of Revenue [Line Items]
Revenues										176	153	236
Resource [Member] | Operating Segments [Member] | Northern Region [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues										1,801	1,387	1,487
Resource [Member] | Operating Segments [Member] | Southern Region [Member]
Disaggregation Of Revenue [Line Items]
Revenues										141,000	80,332	82,961
Resource [Member] | Operating Segments [Member] | Southern Region [Member] | Sawlogs [Member]
Disaggregation Of Revenue [Line Items]
Revenues										81,460	40,993	37,278
Resource [Member] | Operating Segments [Member] | Southern Region [Member] | Pulpwood [Member]
Disaggregation Of Revenue [Line Items]
Revenues										48,585	34,907	35,250
Resource [Member] | Operating Segments [Member] | Southern Region [Member] | Stumpage [Member]
Disaggregation Of Revenue [Line Items]
Revenues										2,434	557	6,245
Resource [Member] | Operating Segments [Member] | Southern Region [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues										8,521	3,875	4,188
Wood Products [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues										680,931	441,157	367,426
Wood Products [Member] | Operating Segments [Member] | Lumber [Member]
Disaggregation Of Revenue [Line Items]
Revenues										464,180	313,083	242,524
Wood Products [Member] | Operating Segments [Member] | Panels [Member]
Disaggregation Of Revenue [Line Items]
Revenues										139,754	73,265	68,440
Wood Products [Member] | Operating Segments [Member] | Residuals [Member]
Disaggregation Of Revenue [Line Items]
Revenues										76,997	54,809	56,462
Real Estate Segment [Member] | Operating Segments [Member]
Disaggregation Of Revenue [Line Items]
Revenues										54,566	30,655	32,604
Real Estate Segment [Member] | Operating Segments [Member] | Rural Real Estate [Member]
Disaggregation Of Revenue [Line Items]
Revenues										36,024	$ 30,655	32,491
Real Estate Segment [Member] | Operating Segments [Member] | Other [Member]
Disaggregation Of Revenue [Line Items]
Revenues										5,690		$ 113
Real Estate Segment [Member] | Operating Segments [Member] | Development Real Estate [Member]
Disaggregation Of Revenue [Line Items]
Revenues										$ 12,852

[1] Intersegment revenues represent logs sold by our Resource segment to the Wood Products segment.