Higher and Better Use Timberlands and Real Estate Development Investments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Real Estate, Land and Land Development Costs [Roll Forward]
Non-current portion, beginning balance	$ 70,374
Plus: Current portion, beginning balance	17,059
Total Balance, beginning	87,433
Non-cash cost of land and improved development	(6,719)
Timber depletion from harvesting activities and basis of timber sold in real estate sales	(2,768)
Capitalized real estate development investments	15,784
Capital expenditures (silviculture)	428
Intersegment transfers	4,989
Total Balance, ending	99,147
Less: Current portion, ending balance	(18,350)
Non-current portion, ending balance	80,797
Capitalized interest	400
Land and Timber
Real Estate, Land and Land Development Costs [Roll Forward]
Non-current portion, beginning balance	59,956
Plus: Current portion, beginning balance	5,096
Total Balance, beginning	65,052
Non-cash cost of land and improved development	(2,165)
Timber depletion from harvesting activities and basis of timber sold in real estate sales	(2,768)
Capitalized real estate development investments	0
Capital expenditures (silviculture)	428
Intersegment transfers	5,808
Total Balance, ending	66,355
Less: Current portion, ending balance	(6,702)
Non-current portion, ending balance	59,653
Development Investments
Real Estate, Land and Land Development Costs [Roll Forward]
Non-current portion, beginning balance	10,418
Plus: Current portion, beginning balance	11,963
Total Balance, beginning	22,381
Non-cash cost of land and improved development	(4,554)
Timber depletion from harvesting activities and basis of timber sold in real estate sales	0
Capitalized real estate development investments	15,784
Capital expenditures (silviculture)	0
Intersegment transfers	(819)
Total Balance, ending	32,792
Less: Current portion, ending balance	(11,648)
Non-current portion, ending balance	$ 21,144