Note 10 - Investments in Affiliates - Summarized Balance Sheet Information for Equity Method Investments (Details) - USD ($) $ in Thousands		Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Current assets		$ 1,347,296	$ 1,574,378	$ 1,586,850	$ 1,573,864	$ 1,827,399
Total assets		2,167,933	2,402,652	2,284,906	2,263,279	2,494,927
Current liabilities		797,594	$ 1,052,026	$ 1,000,084	$ 935,666	1,069,318
Granite’s share of net assets		80,725				23,368	[1]
Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]
Current assets		194,210				34,374	[1]
Noncurrent assets		172,560				78,829	[1]
Total assets		366,770				113,203	[1]
Current liabilities		106,780				23,685	[1]
Long-term liabilities	[2]	59,356				48,104	[1]
Total liabilities		166,136				71,789	[1]
Net assets		$ 200,634				$ 41,414	[1]

[1] These balances do not include amounts held for sale (see Note 2).

[2] This balance is primarily related to local bank debt for equipment purchases and debt associated with our real estate investments.