Segment and Geographical Information - Schedule of Depreciation and Amortization and Capital Expenditures (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Capital expenditures	$ 105,370	$ 129,033	$ 71,483
Depreciation and amortization	153,275	145,957	96,646
Operating Segments | High Purity Cellulose
Segment Reporting Information [Line Items]
Capital expenditures	79,293	92,980	65,691
Depreciation and amortization	123,279	119,231	93,177
Operating Segments | Forest Products
Segment Reporting Information [Line Items]
Capital expenditures	13,667	26,691	4,409
Depreciation and amortization	9,288	6,683	728
Operating Segments | Paperboard
Segment Reporting Information [Line Items]
Capital expenditures	1,446	1,598	17
Depreciation and amortization	15,587	15,674	1,922
Operating Segments | Pulp & Newsprint
Segment Reporting Information [Line Items]
Capital expenditures	4,664	4,938	1,347
Depreciation and amortization	4,323	3,711	505
Operating Segments | Corporate
Segment Reporting Information [Line Items]
Capital expenditures	6,300	2,826	19
Depreciation and amortization	$ 798	$ 658	$ 314