CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue
Total revenue	$ 619,801	$ 563,379
Cost of revenue
Total cost of revenue	579,323	507,096
Gross profit	40,478	56,283
Selling, general and administrative expenses	81,155	61,252
Acquisition and integration expenses	3,323	8,409
Gain on sales of property and equipment	(1,900)	(543)
Operating loss	(42,100)	(12,835)
Other (income) expense
Interest income	(2,816)	(1,521)
Interest expense	4,014	2,435
Equity in income of affiliates	(1,290)	(224)
Other (income) expense, net	(1,762)	268
Total other (income) expense	(1,854)	958
Loss before benefit from income taxes	(40,246)	(13,793)
Benefit from income taxes	(9,165)	(4,131)
Net loss	(31,081)	(9,662)
Amount attributable to non-controlling interests	(3,493)	(1,761)
Net loss attributable to Granite Construction Incorporated	$ (34,574)	$ (11,423)
Net loss per share attributable to common shareholders (See Note 16)
Basic	$ (0.74)	$ (0.29)
Diluted	$ (0.74)	$ (0.29)
Weighted average shares of common stock
Basic	46,699	39,908
Diluted	46,699	39,908
Transportation [Member]
Revenue
Total revenue	$ 338,210	$ 359,145
Cost of revenue
Total cost of revenue	316,960	327,683
Water [Member]
Revenue
Total revenue	99,255	40,041
Cost of revenue
Total cost of revenue	91,136	28,477
Specialty [Member]
Revenue
Total revenue	140,693	118,471
Cost of revenue
Total cost of revenue	125,826	102,735
Materials [Member]
Revenue
Total revenue	41,643	45,722
Cost of revenue
Total cost of revenue	$ 45,401	$ 48,201