v3.20.1

ARO ASSET/LIABILITY (Details) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 28, 2020 | Dec. 28, 2019
Asset Retirement Obligations, Noncurrent [Abstract] |  |
Percent impairment of ARO asset | 100.00% |
Assets held-for-sale | $ 380,000 | $ 896,000

X
- Definition Represents the percentage of impairment of an ARO asset. + References No definition available. + Details
Name: | cuo_PercentageOfImpairmentOfAssetRetirementObligationAsset
Namespace Prefix: | cuo_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AssetRetirementObligationsNoncurrentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of assets held-for-sale that are not part of a disposal group. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 15 -Paragraph 4 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=77912953&loc=d3e400-110220 + Details
Name: | us-gaap_AssetsHeldForSaleNotPartOfDisposalGroup
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant