Commitments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) lease	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Commitments
2019	$ 4,184
2020	229
2021	25
2022	0
2023	0
Thereafter	0
Total	4,438
Commitments:
2019	14,193
2020	9,684
2021	9,288
2022	8,838
2023	8,267
Thereafter	137,626
Total	187,896
Pension contribution requirements in next fiscal year	$ 1,400
Matariki Crown Forest Licenses
Commitments:
Future minimum payments included, years	20 years
Termination notice	35 years
Renewal term	1 year
Number of leases under termination notice | lease	2
Number of fixed term forest leases expiring | lease	2
Operating Leases
Operating Leased Assets [Line Items]
Lease expenses	$ 1,320	$ 1,992	$ 2,049
Leases:
2019	1,234
2020	1,071
2021	898
2022	710
2023	649
Thereafter	40
Total	4,602
Timberland Leases
Operating Leased Assets [Line Items]
Lease expenses	9,521	$ 10,731	$ 10,710
Leases:
2019	8,775
2020	8,384
2021	8,365
2022	8,128
2023	7,618
Thereafter	137,586
Total	$ 178,856
Timberland Leases | United States | Minimum
Operating Leased Assets [Line Items]
Lessee leasing arrangements, operating leases, term of contract (in years)	30 years
Timberland Leases | United States | Maximum
Operating Leased Assets [Line Items]
Lessee leasing arrangements, operating leases, term of contract (in years)	65 years
Timberland Leases | New Zealand | Minimum
Operating Leased Assets [Line Items]
Lessee leasing arrangements, operating leases, term of contract (in years)	30 years
Timberland Leases | New Zealand | Maximum
Operating Leased Assets [Line Items]
Lessee leasing arrangements, operating leases, term of contract (in years)	99 years