Inventories (Schedule of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory Disclosure [Abstract]
Logs	$ 20,133	$ 23,342
Lumber, plywood and veneer	20,889	20,500
Materials and supplies	9,110	8,780
Total inventories	50,132	52,622
Last-in, first-out basis	25,127	29,769
Average cost basis	$ 25,005	$ 22,853