Segment and Geographical Information - Narrative (Details)	12 Months Ended
Dec. 31, 2020
One Customer \| Sales \| Customer Concentration Risk \| High Purity Cellulose
Product Information [Line Items]
Concentration risk percentage	10.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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