Note 3 - Restatement and Recast - Schedule of Condensed Consolidated Financial Statements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Revenue
Total revenue	$ 560,068	$ 653,886
Cost of revenue
Total cost of revenue	527,709	593,794
Gross profit	32,359	60,092
Selling, general and administrative expenses	73,122	70,120
Other costs, net	4,523	6,279
Gain on sales of property and equipment, net	(2,037)	(598)
Operating loss	(43,249)	(15,709)
Other (income) expense
Interest income	(3,762)	(570)
Interest expense	2,891	3,585
Equity in income (loss) of affiliates	(5,187)	(1,289)
Other income, net	(1,950)	1,308
Total other expense, net	(8,008)	3,034
Loss from continuing operations before income taxes	(35,241)	(18,743)
Provision for (benefit from) income taxes on continuing operations	(9,469)	6,352
Net loss from continuing operations		(25,095)
Net Income (loss) from discontinued operations		0
Net loss	(25,772)	(25,095)
Amount attributable to non-controlling interests	2,749	(1,638)
Net loss attributable to Granite Construction Incorporated from continuing operations		(26,733)
Net income (loss) attributable to Granite Construction Incorporated from discontinued operations		0
Net loss attributable to Granite Construction Incorporated	$ (23,023)	$ (26,733)
Net income (loss) per share attributable to common shareholders
Basic continuing operations per share (in dollars per share)		$ (0.58)
Basic discontinued operations per share (in dollars per share)		0
Basic loss per share (in dollars per share)	$ (0.53)	(0.58)
Diluted continuing operations per share (in dollars per share)		(0.58)
Diluted discontinued operations per share (in dollars per share)		0
Diluted loss per share (in dollars per share)	$ (0.53)	$ (0.58)
Basic (in shares)	43,764	45,730
Diluted (in shares)	43,764	45,730
Operating activities
Net loss	$ (25,772)	$ (25,095)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion and amortization	19,733	16,737
Amortization related to long-term debt	472	652
Gain on sale of business	0	(3,278)
Gain on sales of property and equipment, net	(2,037)	(598)
Deferred income taxes	0	2,545
Stock-based compensation	4,828	2,614
Equity in net loss from unconsolidated joint ventures	(911)	3,627
Net income from affiliates		(1,289)
Other non-cash adjustments	(151)	(299)
Changes in assets and liabilities:
Receivables	66,800	85,957
Contract assets, net	(59,307)	(69,819)
Inventories	(11,083)	(13,805)
Contributions to unconsolidated construction joint ventures	(3,350)	(12,840)
Distributions from unconsolidated construction joint ventures and affiliates	2,478	250
Other assets, net	(5,724)	9,652
Accounts payable	(42,955)	(44,028)
Accrued expenses and other liabilities, net	(14,522)	(1,163)
Net cash used in operating activities	(76,688)	(50,180)
Previously Reported Before Reclassification [Member]
Revenue
Total revenue		547,586
Cost of revenue
Total cost of revenue		497,811
Gross profit		49,775
Selling, general and administrative expenses		58,501
Other costs, net		8,214
Gain on sales of property and equipment, net		(332)
Operating loss		(16,608)
Other (income) expense
Interest income		(623)
Interest expense		3,575
Equity in income (loss) of affiliates		306
Other income, net		1,382
Total other expense, net		4,640
Loss from continuing operations before income taxes		(21,248)
Provision for (benefit from) income taxes on continuing operations		(5,331)
Net loss from continuing operations		(15,917)
Net Income (loss) from discontinued operations		6,096
Net loss		(9,821)
Amount attributable to non-controlling interests		(3,118)
Net loss attributable to Granite Construction Incorporated from continuing operations		(19,035)
Net income (loss) attributable to Granite Construction Incorporated from discontinued operations		6,096
Net loss attributable to Granite Construction Incorporated		$ (12,939)
Net income (loss) per share attributable to common shareholders
Basic continuing operations per share (in dollars per share)		$ (0.42)
Basic discontinued operations per share (in dollars per share)		0.13
Basic loss per share (in dollars per share)		(0.29)
Diluted continuing operations per share (in dollars per share)		(0.42)
Diluted discontinued operations per share (in dollars per share)		0.13
Diluted loss per share (in dollars per share)		$ (0.29)
Basic (in shares)		45,730
Diluted (in shares)		45,730
Operating activities
Net loss		$ (9,821)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain on sales of property and equipment, net		(332)
Revision of Prior Period, Adjustment [Member]
Revenue
Total revenue		1,893
Cost of revenue
Total cost of revenue		6,019
Gross profit		(4,126)
Selling, general and administrative expenses		0
Other costs, net		0
Gain on sales of property and equipment, net		0
Operating loss		(4,126)
Other (income) expense
Interest income		0
Interest expense		0
Equity in income (loss) of affiliates		0
Other income, net		0
Total other expense, net		0
Loss from continuing operations before income taxes		(4,126)
Provision for (benefit from) income taxes on continuing operations		(958)
Net loss from continuing operations		(3,168)
Net Income (loss) from discontinued operations		(12,106)
Net loss		(15,274)
Amount attributable to non-controlling interests		1,480
Net loss attributable to Granite Construction Incorporated from continuing operations		(1,688)
Net income (loss) attributable to Granite Construction Incorporated from discontinued operations		(12,106)
Net loss attributable to Granite Construction Incorporated		$ (13,794)
Net income (loss) per share attributable to common shareholders
Basic continuing operations per share (in dollars per share)		$ (0.03)
Basic discontinued operations per share (in dollars per share)		(0.26)
Basic loss per share (in dollars per share)		(0.29)
Diluted continuing operations per share (in dollars per share)		(0.03)
Diluted discontinued operations per share (in dollars per share)		(0.26)
Diluted loss per share (in dollars per share)		$ (0.29)
Basic (in shares)		0
Diluted (in shares)		0
Operating activities
Net loss		$ (15,274)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion and amortization		0
Amortization related to long-term debt		0
Gain on sale of business		2,956
Gain on sales of property and equipment, net		0
Deferred income taxes		0
Stock-based compensation		0
Equity in net loss from unconsolidated joint ventures		0
Net income from affiliates		0
Other non-cash adjustments		0
Changes in assets and liabilities:
Receivables		0
Contract assets, net		2,813
Inventories		0
Contributions to unconsolidated construction joint ventures		0
Distributions from unconsolidated construction joint ventures and affiliates		0
Other assets, net		8,388
Accounts payable		0
Accrued expenses and other liabilities, net		1,117
Net cash used in operating activities		0
Revision of Prior Period, Adjustment [Member] | Discontinued Operations, Disposed of by Sale [Member]
Revenue
Total revenue		104,407
Cost of revenue
Total cost of revenue		89,964
Gross profit		14,443
Selling, general and administrative expenses		11,619
Other costs, net		(1,935)
Gain on sales of property and equipment, net		(266)
Operating loss		5,025
Other (income) expense
Interest income		53
Interest expense		10
Equity in income (loss) of affiliates		(1,595)
Other income, net		(74)
Total other expense, net		(1,606)
Loss from continuing operations before income taxes		6,631
Provision for (benefit from) income taxes on continuing operations		12,641
Net loss from continuing operations		(6,010)
Net Income (loss) from discontinued operations		6,010
Net loss		0
Amount attributable to non-controlling interests		0
Net loss attributable to Granite Construction Incorporated from continuing operations		(6,010)
Net income (loss) attributable to Granite Construction Incorporated from discontinued operations		6,010
Net loss attributable to Granite Construction Incorporated		$ 0
Net income (loss) per share attributable to common shareholders
Basic continuing operations per share (in dollars per share)		$ (0.13)
Basic discontinued operations per share (in dollars per share)		0.13
Basic loss per share (in dollars per share)		0
Diluted continuing operations per share (in dollars per share)		(0.13)
Diluted discontinued operations per share (in dollars per share)		0.13
Diluted loss per share (in dollars per share)		$ 0
Basic (in shares)		0
Diluted (in shares)		0
Operating activities
Net loss		$ 0
Adjustments to reconcile net loss to net cash used in operating activities:
Gain on sales of property and equipment, net		(266)
Restated Before Recasting [Member]
Revenue
Total revenue		549,479
Cost of revenue
Total cost of revenue		503,830
Gross profit		45,649
Selling, general and administrative expenses		58,501
Other costs, net		8,214
Gain on sales of property and equipment, net		(332)
Operating loss		(20,734)
Other (income) expense
Interest income		(623)
Interest expense		3,575
Equity in income (loss) of affiliates		306
Other income, net		1,382
Total other expense, net		4,640
Loss from continuing operations before income taxes		(25,374)
Provision for (benefit from) income taxes on continuing operations		(6,289)
Net loss from continuing operations		(19,085)
Net Income (loss) from discontinued operations		(6,010)
Net loss		(25,095)
Amount attributable to non-controlling interests		(1,638)
Net loss attributable to Granite Construction Incorporated from continuing operations		(20,723)
Net income (loss) attributable to Granite Construction Incorporated from discontinued operations		(6,010)
Net loss attributable to Granite Construction Incorporated		$ (26,733)
Net income (loss) per share attributable to common shareholders
Basic continuing operations per share (in dollars per share)		$ (0.45)
Basic discontinued operations per share (in dollars per share)		(0.13)
Basic loss per share (in dollars per share)		(0.58)
Diluted continuing operations per share (in dollars per share)		(0.45)
Diluted discontinued operations per share (in dollars per share)		(0.13)
Diluted loss per share (in dollars per share)		$ (0.58)
Basic (in shares)		45,730
Diluted (in shares)		45,730
Operating activities
Net loss		$ (25,095)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain on sales of property and equipment, net		(332)
Previously Reported [Member]
Cost of revenue
Gain on sales of property and equipment, net		(598)
Other (income) expense
Net loss		(9,821)
Operating activities
Net loss		(9,821)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion and amortization		16,737
Amortization related to long-term debt		652
Gain on sale of business		(6,234)
Gain on sales of property and equipment, net		(598)
Deferred income taxes		2,545
Stock-based compensation		2,614
Equity in net loss from unconsolidated joint ventures		3,627
Net income from affiliates		(1,289)
Other non-cash adjustments		(299)
Changes in assets and liabilities:
Receivables		85,957
Contract assets, net		(72,632)
Inventories		(13,805)
Contributions to unconsolidated construction joint ventures		(12,840)
Distributions from unconsolidated construction joint ventures and affiliates		250
Other assets, net		1,264
Accounts payable		(44,028)
Accrued expenses and other liabilities, net		(2,280)
Net cash used in operating activities		(50,180)
Construction [Member]
Revenue
Total revenue	503,416	578,266
Cost of revenue
Total cost of revenue	466,711	519,787
Construction [Member] | Previously Reported Before Reclassification [Member]
Revenue
Total revenue		474,935
Cost of revenue
Total cost of revenue		426,743
Construction [Member] | Revision of Prior Period, Adjustment [Member]
Revenue
Total revenue		1,893
Cost of revenue
Total cost of revenue		6,019
Construction [Member] | Revision of Prior Period, Adjustment [Member] | Discontinued Operations, Disposed of by Sale [Member]
Revenue
Total revenue		101,438
Cost of revenue
Total cost of revenue		87,025
Construction [Member] | Restated Before Recasting [Member]
Revenue
Total revenue		476,828
Cost of revenue
Total cost of revenue		432,762
Materials [Member]
Revenue
Total revenue	56,652	75,620
Cost of revenue
Total cost of revenue	$ 60,998	74,007
Materials [Member] | Previously Reported Before Reclassification [Member]
Revenue
Total revenue		72,651
Cost of revenue
Total cost of revenue		71,068
Materials [Member] | Revision of Prior Period, Adjustment [Member]
Revenue
Total revenue		0
Cost of revenue
Total cost of revenue		0
Materials [Member] | Revision of Prior Period, Adjustment [Member] | Discontinued Operations, Disposed of by Sale [Member]
Revenue
Total revenue		2,969
Cost of revenue
Total cost of revenue		2,939
Materials [Member] | Restated Before Recasting [Member]
Revenue
Total revenue		72,651
Cost of revenue
Total cost of revenue		$ 71,068