Restatement - Schedule of Condensed Consolidated Financial Statements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue
Total revenue	$ 1,116,820	$ 1,008,910	$ 2,575,440	$ 2,512,043
Cost of revenue
Total cost of revenue	950,177		2,273,352
Gross profit	166,643	115,055	302,088	272,713
Selling, general and administrative expenses	74,794	61,795	212,479	192,036
Other costs, net	19,843	(490)	37,973	22,401
Gain on sales of property and equipment, net	(1,812)	(949)	(7,793)	(10,462)
Operating income	73,818		59,429
Other (income) expense
Interest income	(4,293)		(11,287)
Interest expense	4,877		11,899
Net income from affiliates	(7,147)		(19,378)	(9,656)
Other expense, net	462		(2,713)
Total other (income) expense, net	(6,101)	(2,789)	29,573	1,747
Income before income taxes	79,919	57,488	29,856	66,991
Benefit from income taxes	22,423	$ (7,710)	21,978	$ 7,310
Amount attributable to non-controlling interests	128		9,723
Net income attributable to Granite Construction Incorporated	$ 57,624		$ 17,601
Net income per share attributable to common shareholders
Basic earnings per share (USD per share)	$ 1.31	$ 1.58	$ 0.40	$ 1.37
Diluted earnings per share (USD per share)	$ 1.13	$ 1.36	$ 0.40	$ 1.25
Weighted average shares outstanding:
Basic (shares)	43,924,000	43,973,000	43,861,000	44,739,000
Diluted (shares)	53,612,000	51,863,000	44,447,000	52,613,000
Operating activities
Net income	$ 57,496	$ 65,198	$ 7,878	$ 59,681
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion and amortization			65,298	61,714
Amortization related to long-term debt			1,689	1,901
Gain on sale of business			0	(3,278)
Deferred income taxes			1,542	(17,819)
Stock-based compensation			8,630	6,151
Granite’s interest in net income (loss)			(4,535)	25,066
Other non-cash adjustments			5,659	38
Changes in assets and liabilities:
Receivables			(286,262)	(94,233)
Contract assets, net			8,315	(91,102)
Inventories			(3,421)	(8,795)
Contributions to unconsolidated construction joint ventures			(18,310)	(44,667)
Distributions from unconsolidated construction joint ventures and affiliates			8,903	7,960
Other assets, net			(6,705)	27,633
Accounts payable			144,721	60,973
Accrued expenses and other liabilities, net			76,915	14,264
Net cash provided by (used in) operating activities			34,198	(14,631)
As Previously Reported
Revenue
Total revenue		1,009,806		2,514,194
Cost of revenue
Total cost of revenue		889,439		2,236,169
Gross profit		120,367		278,025
Selling, general and administrative expenses		61,795		192,036
Other costs, net		(490)		19,445
Gain on sales of property and equipment, net		(949)		(10,462)
Operating income		60,011		77,006
Other (income) expense
Interest income		(1,894)		(3,246)
Interest expense		2,519		10,003
Net income from affiliates		(3,491)		(9,656)
Other expense, net		77		4,646
Total other (income) expense, net		(2,789)		1,747
Income before income taxes		62,800		75,259
Benefit from income taxes		(6,489)		(777)
Net income		69,289
Amount attributable to non-controlling interests		4,104		1,569
Net income attributable to Granite Construction Incorporated		$ 73,393		$ 77,605
Net income per share attributable to common shareholders
Basic earnings per share (USD per share)		$ 1.67		$ 1.73
Diluted earnings per share (USD per share)		$ 1.44		$ 1.56
Weighted average shares outstanding:
Basic (shares)		43,973,000		44,739,000
Diluted (shares)		51,863,000		52,613,000
Operating activities
Net income				$ 76,036
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion and amortization				61,714
Amortization related to long-term debt				1,901
Gain on sale of business				(6,234)
Gain on sales of property and equipment, net				(10,462)
Deferred income taxes				(17,819)
Stock-based compensation				6,151
Granite’s interest in net income (loss)				23,585
Net income from affiliates				(9,656)
Other non-cash adjustments				38
Changes in assets and liabilities:
Receivables				(94,233)
Contract assets, net				(94,933)
Inventories				(8,795)
Contributions to unconsolidated construction joint ventures				(44,667)
Distributions from unconsolidated construction joint ventures and affiliates				7,960
Other assets, net				30,589
Accounts payable				60,973
Accrued expenses and other liabilities, net				3,221
Net cash provided by (used in) operating activities				(14,631)
Restatement Impacts
Revenue
Total revenue		$ (896)		(2,151)
Cost of revenue
Total cost of revenue		4,416		3,161
Gross profit		(5,312)		(5,312)
Selling, general and administrative expenses		0		0
Other costs, net		0		2,956
Gain on sales of property and equipment, net		0		0
Operating income		(5,312)		(8,268)
Other (income) expense
Interest income		0		0
Interest expense		0		0
Net income from affiliates		0		0
Other expense, net		0		0
Total other (income) expense, net		0		0
Income before income taxes		(5,312)		(8,268)
Benefit from income taxes		(1,221)		8,087
Net income		(4,091)
Amount attributable to non-controlling interests		0		0
Net income attributable to Granite Construction Incorporated		$ (4,091)		$ (16,355)
Net income per share attributable to common shareholders
Basic earnings per share (USD per share)		$ (0.09)		$ (0.36)
Diluted earnings per share (USD per share)		$ (0.08)		$ (0.31)
Weighted average shares outstanding:
Basic (shares)		0		0
Diluted (shares)		0		0
Operating activities
Net income				$ (16,355)
Adjustments to reconcile net income 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
Granite’s interest in net income (loss)				1,481
Net income from affiliates				0
Other non-cash adjustments				0
Changes in assets and liabilities:
Receivables				0
Contract assets, net				3,831
Inventories				0
Contributions to unconsolidated construction joint ventures				0
Distributions from unconsolidated construction joint ventures and affiliates				0
Other assets, net				(2,956)
Accounts payable				0
Accrued expenses and other liabilities, net				11,043
Net cash provided by (used in) operating activities				0
As Restated
Revenue
Total revenue		$ 1,008,910		2,512,043
Cost of revenue
Total cost of revenue		893,855		2,239,330
Gross profit		115,055		272,713
Selling, general and administrative expenses		61,795		192,036
Other costs, net		(490)		22,401
Gain on sales of property and equipment, net		(949)		(10,462)
Operating income		54,699		68,738
Other (income) expense
Interest income		(1,894)		(3,246)
Interest expense		2,519		10,003
Net income from affiliates		(3,491)		(9,656)
Other expense, net		77		4,646
Total other (income) expense, net		(2,789)		1,747
Amount attributable to non-controlling interests		4,104		1,569
Net income attributable to Granite Construction Incorporated		$ 69,302		$ 61,250
Net income per share attributable to common shareholders
Basic earnings per share (USD per share)		$ 1.58		$ 1.37
Diluted earnings per share (USD per share)		$ 1.36		$ 1.25
Weighted average shares outstanding:
Basic (shares)		43,973,000		44,739,000
Diluted (shares)		51,863,000		52,613,000
Operating activities
Net income				$ 59,681
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation, depletion and amortization				61,714
Amortization related to long-term debt				1,901
Gain on sale of business				(3,278)
Gain on sales of property and equipment, net				(10,462)
Deferred income taxes				(17,819)
Stock-based compensation				6,151
Granite’s interest in net income (loss)				25,066
Net income from affiliates				(9,656)
Other non-cash adjustments				38
Changes in assets and liabilities:
Receivables				(94,233)
Contract assets, net				(91,102)
Inventories				(8,795)
Contributions to unconsolidated construction joint ventures				(44,667)
Distributions from unconsolidated construction joint ventures and affiliates				7,960
Other assets, net				27,633
Accounts payable				60,973
Accrued expenses and other liabilities, net				14,264
Net cash provided by (used in) operating activities				(14,631)
Construction
Revenue
Total revenue	945,698		2,198,527
Cost of revenue
Total cost of revenue	808,536		1,945,506
Construction | As Previously Reported
Revenue
Total revenue		$ 848,267		2,141,009
Cost of revenue
Total cost of revenue		749,938		1,903,949
Construction | Restatement Impacts
Revenue
Total revenue		(896)		(2,151)
Cost of revenue
Total cost of revenue		4,416		3,161
Construction | As Restated
Revenue
Total revenue		847,371		2,138,858
Cost of revenue
Total cost of revenue		754,354		1,907,110
Materials
Revenue
Total revenue	171,122		376,913
Cost of revenue
Total cost of revenue	$ 141,641		$ 327,846
Materials | As Previously Reported
Revenue
Total revenue		161,539		373,185
Cost of revenue
Total cost of revenue		139,501		332,220
Materials | Restatement Impacts
Revenue
Total revenue		0		0
Cost of revenue
Total cost of revenue		0		0
Materials | As Restated
Revenue
Total revenue		161,539		373,185
Cost of revenue
Total cost of revenue		$ 139,501		$ 332,220