| Standard label: | Health Care Trust Fund, Assets Limited as to Use, Noncurrent |
| Name: | us-gaap:HealthCareTrustFundAssetsLimitedAsToUseNoncurrent |
| Documentation: | Total trust fund assets, excluding those classified as current assets because they are expected to be liquidated to pay current liabilities as of the balance sheet date. |
| Object type: | cm:Concept |
| Data type: | Monetary (xbrli:monetaryItemType) |
| Period type: | As Of (instant) |
| Balance type: | Debit |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:HealthCareTrustFundAssetsLimitedAsToUseNoncurrent |
| Label | Role | Language |
| Health Care Trust Fund, Assets Limited as to Use, Noncurrent | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |
| FASB Accounting Standards Codification 954 810 45 4 | http://fasb.org/us-gaap/role/ref/legacyRef | 954 |
| Part Of Roll Up: |
| us-gaap:LongTermInvestments |