Note 23 - Condensed Consolidated Financial Statements (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended									6 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021		Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Sep. 30, 2022	Dec. 31, 2022	Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Revenue
Total revenue	$ 789,213	$ 1,008,910	$ 849,247	$ 653,886	$ 805,651		$ 1,062,129	$ 964,172	$ 669,913	$ 1,503,133	$ 2,512,043	$ 3,301,256	$ 3,501,865		$ 3,562,459
Cost of revenue
Total cost of revenue		893,855	751,681	593,794						1,345,475	2,239,330	2,931,762	3,139,220		3,217,671
Total gross profit from reportable segments	96,781	115,055	97,566	60,092	62,446		119,935	116,946	63,318	157,658	272,713	369,494	362,645		344,788
Selling, general and administrative expenses		61,795	60,121	70,120						130,241	192,036	272,610	303,015		316,284
Other costs, net (See Note 1)		(490)	16,612	6,279						22,891	22,401	24,120	101,351		37,089
Gain on sales of property and equipment, net (see Note 11)		(949)	(8,915)	(598)						(9,513)	(10,462)	(12,617)	(66,439)		(6,930)
Operating income (loss)		54,699	29,748	(15,709)						14,039	68,738	85,381	24,718		(158,345)
Other (income) expense
Interest income		(1,894)	(782)	(570)						(1,352)	(3,246)	(6,528)	(1,176)		(3,096)
Interest expense		2,519	3,899	3,585						7,484	10,003	12,624	20,739		24,200
Equity in income of affiliates, net		(3,491)	(4,876)	(1,289)						(6,165)	(9,656)	(13,571)	(12,586)		(8,783)
Other income, net		77	3,261	1,308						4,569	4,646	(1,039)	4,386		4,203
Total other (income) expense, net		(2,789)	1,502	3,034						4,536	1,747	(6,436)	2,591		8,118
Income (loss) before income taxes		57,488	28,246	(18,743)						9,503	66,991	91,817	22,127		(166,463)
Provision for (benefit from) income taxes		(7,710)	8,668	6,352						15,020	7,310	12,960	19,713		(282)
Net income	19,176	65,198	19,578	(25,095)	(20,433)		32,423	55,747	(65,323)	(5,517)	59,681	78,857	2,414		(166,181)
Amount attributable to non-controlling interests		4,104	(897)	(1,638)						(2,535)	1,569	4,445	7,682		21,064
Net income (loss) attributable to Granite Construction Incorporated	$ 22,052	$ 69,302	18,681	(26,733)	$ (13,213)		$ 35,043	$ 54,461	$ (66,195)	(8,052)	$ 61,250	$ 83,302	$ 10,096		$ (145,117)
Net income (loss) from continuing operations			19,578	(25,095)						(5,517)
Net Income (loss) from discontinued operations				0						0
Net income (loss) attributable to Granite Construction Incorporated from continuing operations			18,681	(26,733)						(8,052)
Net income attributable to Granite Construction Incorporated from discontinued operations			$ 0	$ 0						$ 0
Net income per share attributable to common shareholders (see Note 18):
Basic earnings (loss) per share (in dollars per share)	$ 0.50	$ 1.58	$ 0.42	$ (0.58)	$ (0.29)		$ 0.76	$ 1.19	$ (1.45)	$ (0.18)	$ 1.37	$ 1.87	$ 0.22		$ (3.18)
Diluted earnings (loss) per share (in dollars per share)	$ 0.46	$ 1.36	$ 0.39	$ (0.58)	$ (0.29)		$ 0.73	$ 1.14	$ (1.45)	$ (0.18)	$ 1.25	$ 1.70	$ 0.21		$ (3.18)
Basic (in shares)		43,973	44,534	45,730						45,128	44,739	44,485	45,788		45,614
Diluted (in shares)		51,863	52,295	45,730						45,128	52,613	52,326	47,599		45,614
Basic continuing operations per share (in dollars per share)			$ 0.42	$ (0.58)						$ (0.18)
Basic discontinued operations per share (in dollars per share)			0							0
Diluted continuing operations per share (in dollars per share)			0.39	(0.58)						(0.18)
Diluted discontinued operations per share (in dollars per share)			$ 0	$ 0						$ 0
Current assets
Cash and cash equivalents	$ 293,991	$ 255,084	$ 175,022	$ 360,911	$ 395,647					$ 175,022	$ 255,084	$ 293,991	$ 395,647
Short-term marketable securities	39,374	39,873	45,000	14,953	0					45,000	39,873	39,374	0
Receivables, net	463,987	618,144	527,277	380,502	464,588	[1]				527,277	618,144	463,987	464,588	[1]
Contract assets	241,916	237,407	190,187	172,641	145,437					190,187	237,407	241,916	145,437
Inventories	86,809	81,296	78,634	74,356	61,965					78,634	81,296	86,809	61,965
Equity in construction joint ventures	183,808	185,343	187,028	191,183	189,911					187,028	185,343	183,808	189,911
Other current assets	37,411	157,231	160,923	167,679	177,210					160,923	157,231	37,411	177,210
Current assets held for sale	0	0	222,779	211,639	392,641					222,779	0	0	392,641
Total current assets	1,347,296	1,574,378	1,586,850	1,573,864	1,827,399					1,586,850	1,574,378	1,347,296	1,827,399
Property and equipment, net	509,210	500,827	464,593	450,250	433,504	[1]				464,593	500,827	509,210	433,504	[1]
Long-term marketable securities	26,569	21,575	21,675	21,775	15,600					21,675	21,575	26,569	15,600
Investments in affiliates	80,725	78,663	23,203	22,987	23,368					23,203	78,663	80,725	23,368
Goodwill	73,703	73,704	53,715	53,715	53,715					53,715	73,704	73,703	53,715
Right of use assets	49,079	49,590	45,404	48,920	49,312					45,404	49,590	49,079	49,312
Deferred income taxes, net	22,208	45,650	25,458	25,880	24,141					25,458	45,650	22,208	24,141
Other noncurrent assets	59,143	58,265	64,008	65,888	67,888					64,008	58,265	59,143	67,888
Segment assets as of period end (1)	2,167,933	2,402,652	2,284,906	2,263,279	2,494,927					2,284,906	2,402,652	2,167,933	2,494,927
Current liabilities
Current maturities of long-term debt	1,447	1,438	1,429	8,735	8,727					1,429	1,438	1,447	8,727
Accounts payable	334,392	398,285	331,728	285,390	324,313					331,728	398,285	334,392	324,313
Contract liabilities	173,286	191,037	179,322	160,994	200,041					179,322	191,037	173,286	200,041
Accrued expenses and other current liabilities	288,469	461,266	440,899	438,441	452,829					440,899	461,266	288,469	452,829
Current liabilities held for sale	0	0	46,706	42,106	83,408					46,706	0	0	83,408
Total current liabilities	797,594	1,052,026	1,000,084	935,666	1,069,318					1,000,084	1,052,026	797,594	1,069,318
Long-term debt	286,934	286,872	286,801	290,549	331,191					286,801	286,872	286,934	331,191
Lease liabilities	32,170	32,701	31,182	32,682	32,928					31,182	32,701	32,170	32,928
Other long-term liabilities	64,199	60,664	61,868	62,493	64,071					61,868	60,664	64,199	64,071
Commitments and contingencies (see Note 20)
Equity
Preferred stock	0	0	0	0	0					0	0	0	0
Common stock	437	437	441	454	458					441	437	437	458
Additional paid-in capital	470,407	468,662	467,159	515,262	559,752					467,159	468,662	470,407	559,752
Accumulated other comprehensive income (loss)	788	535	2,388	1,573	(3,359)					2,388	535	788	(3,359)
Retained earnings	481,384	465,134	401,667	388,756	410,831					401,667	465,134	481,384	410,831
Total Granite Construction Incorporated shareholders’ equity	953,016	934,768	871,655	906,045	967,682					871,655	934,768	953,016	967,682
Non-controlling interests	32,129	35,621	33,316	35,844	27,881					33,316	35,621	32,129	27,881
Total equity	985,145	970,389	904,971	941,889	995,563					904,971	970,389	985,145	995,563		$ 991,610	$ 1,178,416
Total liabilities and equity	$ 2,167,933	2,402,652	2,284,906	2,263,279	$ 2,494,927					2,284,906	2,402,652	2,167,933	2,494,927
Previously Reported [Member]
Revenue
Total revenue		1,009,806	768,286	547,586						1,315,872	2,514,194
Cost of revenue
Total cost of revenue		889,439	689,806	497,811						1,187,617	2,236,169
Total gross profit from reportable segments		120,367	78,480	49,775						128,255	278,025
Selling, general and administrative expenses		61,795	53,162	58,501						111,663	192,036
Other costs, net (See Note 1)		(490)	20,177	8,214						28,391	19,445
Gain on sales of property and equipment, net (see Note 11)		(949)	(385)	(332)						(717)	(10,462)
Operating income (loss)		60,011	5,526	(16,608)						(11,082)	77,006
Other (income) expense
Interest income		(1,894)	(782)	(623)						(1,405)	(3,246)
Interest expense		2,519	3,896	3,575						7,471	10,003
Equity in income of affiliates, net		(3,491)	(541)	306						(235)	(9,656)
Other income, net		77	3,357	1,382						4,739	4,646
Total other (income) expense, net		(2,789)	5,930	4,640						10,570	1,747
Income (loss) before income taxes		62,800	(404)	(21,248)						(21,652)	75,259
Provision for (benefit from) income taxes		(6,489)	2,549	(5,331)						(2,782)	(777)
Net income		69,289	16,568	(9,821)						6,747	76,036
Amount attributable to non-controlling interests		4,104	583	(3,118)						(2,535)	1,569
Net income (loss) attributable to Granite Construction Incorporated		$ 73,393	17,151	(12,939)						4,212	$ 77,605
Net income (loss) from continuing operations			(2,953)	(15,917)						(18,870)
Net Income (loss) from discontinued operations			19,521	6,096						25,617
Net income (loss) attributable to Granite Construction Incorporated from continuing operations			(2,370)	(19,035)						(21,405)
Net income attributable to Granite Construction Incorporated from discontinued operations			$ 19,521	$ 6,096						$ 25,617
Net income per share attributable to common shareholders (see Note 18):
Basic earnings (loss) per share (in dollars per share)		$ 1.67	$ 0.39	$ (0.29)						$ 0.10	$ 1.73
Diluted earnings (loss) per share (in dollars per share)		$ 1.44	$ 0.39	$ (0.29)						$ 0.10	$ 1.56
Basic (in shares)		43,973	44,534	45,730						45,128	44,739
Diluted (in shares)		51,863	44,534	45,730						45,128	52,613
Basic continuing operations per share (in dollars per share)			$ (0.05)	$ (0.42)						$ (0.47)
Basic discontinued operations per share (in dollars per share)			0.44	0.13						0.57
Diluted continuing operations per share (in dollars per share)			(0.05)	(0.42)						(0.47)
Diluted discontinued operations per share (in dollars per share)			$ 0.44	$ 0.13						$ 0.57
Current assets
Cash and cash equivalents		$ 255,084	$ 175,022	$ 360,911						$ 175,022	$ 255,084
Short-term marketable securities		39,873	45,000	14,953						45,000	39,873
Receivables, net		618,144	527,277	380,502						527,277	618,144
Contract assets		241,238	190,187	180,023						190,187	241,238
Inventories		81,296	78,634	74,356						78,634	81,296
Equity in construction joint ventures		186,824	187,028	191,183						187,028	186,824
Other current assets		157,231	167,349	179,024						167,349	157,231
Current assets held for sale			222,779	211,774						222,779
Total current assets		1,579,690	1,593,276	1,592,726						1,593,276	1,579,690
Property and equipment, net		500,827	464,593	450,250						464,593	500,827
Long-term marketable securities		21,575	21,675	21,775						21,675	21,575
Investments in affiliates		78,663	23,203	22,987						23,203	78,663
Goodwill		73,704	53,715	53,715						53,715	73,704
Right of use assets		49,590	45,404	48,920						45,404	49,590
Deferred income taxes, net		45,650	25,458	25,880						25,458	45,650
Other noncurrent assets		58,265	64,008	65,888						64,008	58,265
Segment assets as of period end (1)		2,407,964	2,291,332	2,282,141						2,291,332	2,407,964
Current liabilities
Current maturities of long-term debt		1,438	1,429	8,735						1,429	1,438
Accounts payable		398,285	331,728	285,390						331,728	398,285
Contract liabilities		191,037	179,322	165,358						179,322	191,037
Accrued expenses and other current liabilities		450,223	435,061	439,525						435,061	450,223
Current liabilities held for sale			46,706	40,246						46,706
Total current liabilities		1,040,983	994,246	939,254						994,246	1,040,983
Long-term debt		286,872	286,801	290,549						286,801	286,872
Lease liabilities		32,701	31,182	32,682						31,182	32,701
Other long-term liabilities		60,664	61,868	62,493						61,868	60,664
Equity
Preferred stock		0	0	0						0	0
Common stock		437	441	454						441	437
Additional paid-in capital		468,662	467,159	515,262						467,159	468,662
Accumulated other comprehensive income (loss)		535	2,388	1,573						2,388	535
Retained earnings		481,489	413,931	402,550						413,931	481,489
Total Granite Construction Incorporated shareholders’ equity		951,123	883,919	919,839						883,919	951,123
Non-controlling interests		35,621	33,316	37,324						33,316	35,621
Total equity		986,744	917,235	957,163						917,235	986,744
Total liabilities and equity		2,407,964	2,291,332	2,282,141						2,291,332	2,407,964
Revision of Prior Period, Adjustment [Member]
Revenue
Total revenue		(896)	(1,893)	1,893							(2,151)
Cost of revenue
Total cost of revenue		4,416	(6,018)	6,019							3,161
Total gross profit from reportable segments		(5,312)	4,125	(4,126)							(5,312)
Other costs, net (See Note 1)											2,956
Operating income (loss)		(5,312)	4,125	(4,126)							(8,268)
Other (income) expense
Income (loss) before income taxes		(5,312)	4,125	(4,126)							(8,268)
Provision for (benefit from) income taxes		(1,221)	911	(958)						(48)	8,087
Net income		(4,091)	3,010	(15,274)						(12,264)	(16,355)
Amount attributable to non-controlling interests			(1,480)	1,480
Net income (loss) attributable to Granite Construction Incorporated		$ (4,091)	1,530	(13,794)						(12,264)	$ (16,355)
Net income (loss) from continuing operations			3,214	(3,168)						48
Net Income (loss) from discontinued operations			(204)	(12,106)						(12,312)
Net income (loss) attributable to Granite Construction Incorporated from continuing operations			1,734	(1,688)						48
Net income attributable to Granite Construction Incorporated from discontinued operations			$ (204)	$ (12,106)						$ (12,312)
Net income per share attributable to common shareholders (see Note 18):
Basic earnings (loss) per share (in dollars per share)		$ (0.09)	$ 0.03	$ (0.29)						$ (0.28)	$ (0.36)
Diluted earnings (loss) per share (in dollars per share)		$ (0.08)	0.03	(0.29)						(0.28)	$ (0.31)
Basic continuing operations per share (in dollars per share)			0.04	(0.03)
Basic discontinued operations per share (in dollars per share)			(0.01)	(0.26)						(0.28)
Diluted continuing operations per share (in dollars per share)			0.04	(0.03)
Diluted discontinued operations per share (in dollars per share)			$ (0.01)	$ (0.26)						$ (0.28)
Current assets
Contract assets		$ (3,831)		$ (7,382)							$ (3,831)
Equity in construction joint ventures		(1,481)									(1,481)
Other current assets			$ (6,426)	(11,345)						$ (6,426)
Total current assets		(5,312)	(6,426)	(18,862)						(6,426)	(5,312)
Segment assets as of period end (1)		(5,312)	(6,426)	(18,862)						(6,426)	(5,312)
Current liabilities
Contract liabilities				(4,364)
Accrued expenses and other current liabilities		11,043	5,838	(1,084)						5,838	11,043
Current liabilities held for sale				1,860
Total current liabilities		11,043	5,838	(3,588)						5,838	11,043
Equity
Retained earnings		(16,355)	(12,264)	(13,794)						(12,264)	(16,355)
Total Granite Construction Incorporated shareholders’ equity		(16,355)	(12,264)	(13,794)						(12,264)	(16,355)
Non-controlling interests			0	(1,480)						0
Total equity		(16,355)	(12,264)	(15,274)						(12,264)	(16,355)
Total liabilities and equity		(5,312)	(6,426)	(18,862)						(6,426)	(5,312)
Restated Before Recasting [Member]
Revenue
Total revenue			766,393	549,479						1,315,872
Cost of revenue
Total cost of revenue			683,788	503,830						1,187,617
Total gross profit from reportable segments			82,605	45,649						128,255
Selling, general and administrative expenses			53,162	58,501						111,663
Other costs, net (See Note 1)			20,177	8,214						28,391
Gain on sales of property and equipment, net (see Note 11)			(385)	(332)						(717)
Operating income (loss)			9,651	(20,734)						(11,082)
Other (income) expense
Interest income			(782)	(623)						(1,405)
Interest expense			3,896	3,575						7,471
Equity in income of affiliates, net			(541)	306						(235)
Other income, net			3,357	1,382						4,739
Total other (income) expense, net			5,930	4,640						10,570
Income (loss) before income taxes			3,721	(25,374)						(21,652)
Provision for (benefit from) income taxes			3,460	(6,289)						(2,830)
Net income			19,578	(25,095)						(5,517)
Amount attributable to non-controlling interests			(897)	(1,638)						(2,535)
Net income (loss) attributable to Granite Construction Incorporated			18,681	(26,733)						(8,052)
Net income (loss) from continuing operations			261	(19,085)						(18,822)
Net Income (loss) from discontinued operations			19,317	(6,010)						13,305
Net income (loss) attributable to Granite Construction Incorporated from continuing operations			(636)	(20,723)						(21,357)
Net income attributable to Granite Construction Incorporated from discontinued operations			$ 19,317	$ (6,010)						$ 13,305
Net income per share attributable to common shareholders (see Note 18):
Basic earnings (loss) per share (in dollars per share)			$ 0.42	$ (0.58)						$ (0.18)
Diluted earnings (loss) per share (in dollars per share)			$ 0.42	$ (0.58)						$ (0.18)
Basic (in shares)			44,534	45,730						45,128
Diluted (in shares)			44,534	45,730						45,128
Basic continuing operations per share (in dollars per share)			$ (0.01)	$ (0.45)						$ (0.47)
Basic discontinued operations per share (in dollars per share)			0.43	(0.13)						0.29
Diluted continuing operations per share (in dollars per share)			(0.01)	(0.45)						(0.47)
Diluted discontinued operations per share (in dollars per share)			$ 0.43	$ (0.13)						$ 0.29
Revision of Prior Period, Reclassification, Adjustment [Member]
Revenue
Total revenue			$ 82,854	$ 104,407						$ 187,261
Cost of revenue
Total cost of revenue			67,893	89,964						157,858
Total gross profit from reportable segments			14,961	14,443						29,403
Selling, general and administrative expenses			6,959	11,619						18,578
Other costs, net (See Note 1)			(3,565)	(1,935)						(5,500)
Gain on sales of property and equipment, net (see Note 11)			(8,530)	(266)						(8,796)
Operating income (loss)			20,097	5,025						25,121
Other (income) expense
Interest income				53						53
Interest expense			3	10						13
Equity in income of affiliates, net			(4,335)	(1,595)						(5,930)
Other income, net			(96)	(74)						(170)
Total other (income) expense, net			(4,428)	(1,606)						(6,034)
Income (loss) before income taxes			24,525	6,631						31,155
Provision for (benefit from) income taxes			5,208	12,641						17,850
Net income			0
Net income (loss) from continuing operations			19,317	(6,010)						13,305
Net Income (loss) from discontinued operations			(19,317)	6,010						(13,305)
Net income (loss) attributable to Granite Construction Incorporated from continuing operations			19,317	(6,010)						13,305
Net income attributable to Granite Construction Incorporated from discontinued operations			$ (19,317)	$ 6,010						$ (13,305)
Net income per share attributable to common shareholders (see Note 18):
Diluted earnings (loss) per share (in dollars per share)			$ (0.03)
Basic continuing operations per share (in dollars per share)			0.43	$ (0.13)						$ 0.29
Basic discontinued operations per share (in dollars per share)			(0.43)	0.13						(0.29)
Diluted continuing operations per share (in dollars per share)			0.40	(0.13)						0.29
Diluted discontinued operations per share (in dollars per share)			$ (0.43)	$ 0.13						$ (0.29)
Construction [Member]
Revenue
Total revenue		847,371	$ 713,221	$ 578,266						$ 1,291,487	2,138,858	2,803,935	3,076,190		3,181,697
Cost of revenue
Total cost of revenue		754,354	632,969	519,787						1,152,756	1,907,110	2,500,054	2,772,962		2,901,528
Construction [Member] | Previously Reported [Member]
Revenue
Total revenue		848,267	632,260	474,935						1,107,195	2,141,009
Cost of revenue
Total cost of revenue		749,938	571,094	426,743						997,837	1,903,949
Construction [Member] | Revision of Prior Period, Adjustment [Member]
Revenue
Total revenue		(896)	(1,893)	1,893							(2,151)
Cost of revenue
Total cost of revenue		4,416	(6,018)	6,019							3,161
Construction [Member] | Restated Before Recasting [Member]
Revenue
Total revenue			630,367	476,828						1,107,195
Cost of revenue
Total cost of revenue			565,076	432,762						997,837
Construction [Member] | Revision of Prior Period, Reclassification, Adjustment [Member]
Revenue
Total revenue			82,854	101,438						184,292
Cost of revenue
Total cost of revenue			67,893	87,025						154,919
Materials [Member]
Revenue
Total revenue		161,539	136,026	75,620						211,646	373,185	497,321	425,675		380,762
Cost of revenue
Total cost of revenue		139,501	118,712	74,007						192,719	332,220	$ 431,708	$ 366,258		$ 316,143
Materials [Member] | Previously Reported [Member]
Revenue
Total revenue		161,539	136,026	72,651						208,677	373,185
Cost of revenue
Total cost of revenue		$ 139,501	118,712	71,068						189,780	$ 332,220
Materials [Member] | Restated Before Recasting [Member]
Revenue
Total revenue			136,026	72,651						208,677
Cost of revenue
Total cost of revenue			$ 118,712	71,068						189,780
Materials [Member] | Revision of Prior Period, Reclassification, Adjustment [Member]
Revenue
Total revenue				2,969						2,969
Cost of revenue
Total cost of revenue				$ 2,939						$ 2,939

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