Note 16 - Contingencies - Legal Proceedings (Details Textual) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
Apr. 29, 2021	Mar. 31, 2021	Sep. 30, 2021
Loss Contingency Accrual, Ending Balance			$ 66
Gain (Loss) Related to Litigation Settlement, Total			(66)
Police Retirement System of St. Louis v. Granite Construction Incorporated, et al. [Member]
Litigation Settlement, Amount Awarded to Other Party	$ 129
Loss Contingency, Receivable, Ending Balance	$ 63		63
Gain (Loss) Related to Litigation Settlement, Total		$ (66)
Damages Related to Salesforce Tower Office Building in San Francisco [Member] \| Potential Legal Action Not Yet Taken Against the Company [Member]
Loss Contingency, Estimate of Possible Loss			$ 100

Amount of gain (loss) recognized in settlement of litigation and insurance claims. Excludes claims within an insurance entity's normal claims settlement process.

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Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

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Amount of loss contingency liability.

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Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

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Amount of receivable related to a loss contingency accrual. For example, an insurance recovery receivable.

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