Merger with Deltic - Summary of Estimated Fair Value of Identifiable Assets Acquired and Liabilities Assumed (Details) $ in Thousands	Feb. 20, 2018 USD ($)
ASSETS
Cash and cash equivalents	$ 3,419
Customer receivables, net	12,709
Inventories	17,316
Other current assets	8,276
Real estate held for development and sale	79,000
Property, plant and equipment	265,901
Timber and timberlands	1,060,000
Trade name and customer relationships intangibles	19,000
Other long-term assets	2,010
Total assets acquired	1,467,631
LIABILITIES
Accounts payable and accrued liabilities	12,604
Current portion of pension and other postretirement employee benefits	754
Long-term debt	229,968
Pension and other postretirement employee benefits	36,155
Deferred tax liabilities, net	44,439
Other long-term liabilities	936
Total liabilities assumed	324,856
Net assets acquired	$ 1,142,775