Equity - Schedule of Stockholders Equity (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018		Mar. 31, 2017
Stockholders Equity Rollforward [Line Items]
Stockholders' equity, beginning balance		$ 992,805		$ 922,591
Net (loss) income		(9,662)		(23,851)
Purchase of common stock		(6,119)	[1]	(6,448)	[2]
Dividends on common stock		(5,206)		(5,176)
Effect of adopting Topic 606		(15,201)
Other transactions with shareholders and employees	[3]	8,277		8,943
Stockholders' equity, ending balance		964,894		896,059
Granite Construction [Member]
Stockholders Equity Rollforward [Line Items]
Stockholders' equity, beginning balance		945,108		885,988
Net (loss) income		(11,423)		(23,790)
Purchase of common stock		(6,119)	[1]	(6,448)	[2]
Dividends on common stock		(5,206)		(5,176)
Effect of adopting Topic 606		(15,201)
Other transactions with shareholders and employees	[3]	8,277		8,943
Stockholders' equity, ending balance		915,436		859,517
Noncontrolling Interest [Member]
Stockholders Equity Rollforward [Line Items]
Stockholders' equity, beginning balance		47,697		36,603
Net (loss) income		1,761		(61)
Purchase of common stock		0	[1]	0	[2]
Dividends on common stock		0		0
Effect of adopting Topic 606		0
Other transactions with shareholders and employees	[3]	0		0
Stockholders' equity, ending balance		$ 49,458		$ 36,542

[1] Represents 104,000 shares purchased in connection with employee tax withholding for restricted stock units vested under our 2012 Equity Incentive Plan.

[2] Represents 131,000 shares purchased in connection with employee tax withholding for restricted stock units vested under our 2012 Equity Incentive Plan.

[3] Amounts are comprised primarily of amortized restricted stock units.