v3.26.3
Construction Joint Ventures - Schedule of Unconsolidated Construction Joint Ventures Revenue and Costs (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Guarantor Obligations [Line Items]        
Cost of revenue $ 1,430,571 $ 1,172,950 $ 3,450,232 $ 2,715,513
Changes to net income (loss) 10,391 109,397 (297,582) 161,415
Granite’s interest in net income (loss)     (13,098) (5,401)
Collaborative Arrangement        
Guarantor Obligations [Line Items]        
Revenue 2,789 6,288 20,719 17,169
Cost of revenue 3,042 5,091 8,733 12,776
Granite’s interest in gross profit (loss) (253) 1,197 11,986 4,393
Granite’s interest in net income (loss) 2 1,587 13,098 5,401
Collaborative Arrangement | Corporate Joint Venture        
Guarantor Obligations [Line Items]        
Revenue 4,707 17,893 19,988 21,554
Cost of revenue 12,063 7,754 22,604 40,574
Changes to net income (loss) (6,455) 11,390 307 (15,583)
Collaborative Arrangement | Co-venturer | Other Partners Interest in Partnerships        
Guarantor Obligations [Line Items]        
Revenue 1,918 11,605 (731) 4,385
Cost of revenue 9,021 2,663 13,871 27,798
Changes to net income (loss) $ (6,457) $ 9,803 $ (12,791) $ (20,984)