Other Assets - Asset Balances (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Long-term and prepaid and secondary roads	$ 7,072	$ 6,363
Deferred financing costs related to revolving debt	213	341
Pacific Northwest
Finite-Lived Intangible Assets [Line Items]
Long-term and prepaid and secondary roads	4,000	3,696
New Zealand
Finite-Lived Intangible Assets [Line Items]
Long-term and prepaid and secondary roads	3,072	2,667
Software Costs
Finite-Lived Intangible Assets [Line Items]
Capitalized software costs	$ 3,776	$ 4,092