Commitments and Contingencies Commitments and Contingencies Additional Information (Details)	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Firm price contracts, percentage of expected average monthly natural gas and electricity needs covered	43.00%

Percentage Of Expected Natural Gas Requirement Covered Under Contract For Next Fiscal Year

No definition available.

Name:	clw_PercentageOfExpectedNaturalGasRequirementCoveredUnderContractForNextFiscalYear
Namespace Prefix:	clw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant