Segment and Geographical Information - Narrative (Details) - customer	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting [Abstract]
Number of significant customers	0	3	3

Number of single external customers that amount to 10 percent or more of entity revenues, including the disclosure of that fact, the total amount of revenues from each such customer, and the identity of the reportable segment or segments reporting the revenues.

No definition available.

Name:	ryam_NumberofSignificantCustomers
Namespace Prefix:	ryam_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration