Note 9 - Receivables, Net (Details Textual) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Working Capital (Deficit)	$ 24.9	$ 20.4
Percentage of Net Receivables, Individually, Maximum	10.00%
Police Retirement System of St. Louis v. Granite Construction Incorporated, et al. [Member]
Insurance Settlements Receivable	$ 63.0
Loan to Partner in Joint Ventures [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate	3.00%