| Standard label: | Investments in Debt and Equity Instruments, Cash and Cash Equivalents, Unrealized and Realized Gains (Losses) [Text Block] |
| Name: | us-gaap:InvestmentsInDebtAndEquityInstrumentsCashAndCashEquivalentsUnrealizedAndRealizedGainsLossesTextBlock |
| Documentation: | The entire disclosure for cash, cash equivalents, investments in debt and equity instruments (including cost and equity investees and related income statement amounts), equity and cost method investments, investments in joint ventures and any other investment. |
| Object type: | cm:Level1TextBlock |
| Data type: | Text Block (HTML) (nonnum:textBlockItemType) |
| Period type: | For Period (duration) |
| Balance type: | (no balance type) |
| Abstract: | false |
| Workiva Wdesk Taxonomy Analyzer: | us-gaap:InvestmentsInDebtAndEquityInstrumentsCashAndCashEquivalentsUnrealizedAndRealizedGainsLossesTextBlock |
| Examples of this text block disclosure: | InvestmentsInDebtAndEquityInstrumentsCashAndCashEquivalentsUnrealizedAndRealizedGainsLosses |
| Label | Role | Language |
| Investments in Debt and Equity Instruments, Cash and Cash Equivalents, Unrealized and Realized Gains (Losses) [Text Block] | http://www.xbrl.org/2003/role/label | en-US |
| Reference | Role | Topic |