XML 43 R73.htm IDEA: XBRL DOCUMENT
v3.20.1

Post Retirement Benefits - Multiemployer Plans (Details) | 12 Months Ended
--- | ---
Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Aug. 06, 2017 $ / h
Multiemployer plans: |  |  |
Certified zone status, percent funded limit for red status | 65.00% |  |
Certified zone status, percent funded limit for yellow status | 80.00% |  |
Certified zone status, percent funded limit for green status | 80.00% |  |
Multi-employer plan contributions | $ | $ 971,000 | $ 760,000 |
Multiemployer plan, postretirement benefit |  |  |
Multiemployer plans: |  |  |
Maximum percentage of total contribution | 5.00% |  |
Multiemployer plans, collective-bargaining arrangement, maximum hours of work per week for employer contribution | 40 hours |  |
Multiemployer plans, collective-bargaining arrangement, rate of employer contribution | $ / h |  |  | 1.55

X
- Definition Multiemployer Plans, Certified Zone Status, Percent Funded Limit for Green Status + References No definition available. + Details
Name: | cmt_MultiemployerPlansCertifiedZoneStatusPercentFundedLimitForGreenStatus
Namespace Prefix: | cmt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Multiemployer Plans, Certified Zone Status, Percent Funded Limit for Red Status + References No definition available. + Details
Name: | cmt_MultiemployerPlansCertifiedZoneStatusPercentFundedLimitForRedStatus
Namespace Prefix: | cmt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Multiemployer Plans, Certified Zone Status, Percent Funded Limit for Yellow Status + References No definition available. + Details
Name: | cmt_MultiemployerPlansCertifiedZoneStatusPercentFundedLimitForYellowStatus
Namespace Prefix: | cmt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Multiemployer Plans, Collective-Bargaining Arrangement, Maximum Hours of Work Per Week for Employer Contribution + References No definition available. + Details
Name: | cmt_MultiemployerPlansCollectiveBargainingArrangementMaximumHoursOfWorkPerWeekForEmployerContribution
Namespace Prefix: | cmt_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Multiemployer Plans, Collective-Bargaining Arrangement, Rate of Employer Contribution + References No definition available. + Details
Name: | cmt_MultiemployerPlansCollectiveBargainingArrangementRateOfEmployerContribution
Namespace Prefix: | cmt_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | duration

X
- Definition Multiemployer Plans, Maximum Percentage of Total Contribution + References No definition available. + Details
Name: | cmt_MultiemployerPlansMaximumPercentageOfTotalContribution
Namespace Prefix: | cmt_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contributions made to multiemployer plan by employer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
Name: | us-gaap_MultiemployerPlanContributionsByEmployer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_MultiemployerPlansLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_MultiemployerPlanTypeAxis=us-gaap_MultiemployerPlansPostretirementBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |