Equity (Details) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance				$ 817,106		$ 786,344
Purchase of common stock				(3,366)	[1]	(4,751)	[2]
Other transactions with shareholders	[3]			6,816		10,505
Transactions with noncontrolling interests, net				(1,808)		15,174
Net Loss Attributable to Parent		$ 30,759	$ 15,282	31,812		8,370
Comprehensive income (loss):
Net income		32,180	14,105	33,109		15,051
Dividends on common stock				(15,352)		(15,260)
Stockholders' equity, ending balance		836,505	807,063	$ 836,505		$ 807,063
Shares Purchased for Tax Withholding for Share Based Compensation				103,000		123,000
Granite Construction [Member]
Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance				$ 794,385		$ 781,940
Purchase of common stock				(3,366)	[1]	(4,751)	[2]
Other transactions with shareholders	[3]			6,816		10,505
Transactions with noncontrolling interests, net				0		0
Net Loss Attributable to Parent				31,812
Comprehensive income (loss):
Net income						8,370
Dividends on common stock				(15,352)		(15,260)
Stockholders' equity, ending balance		814,295	780,804	814,295		780,804
Noncontrolling Interest [Member]
Stockholders' Equity [Roll Forward]
Stockholders' equity, beginning balance				22,721		4,404
Purchase of common stock				0	[1]	0	[2]
Other transactions with shareholders	[3]			0		0
Transactions with noncontrolling interests, net				(1,808)		15,174
Comprehensive income (loss):
Net income				1,297		6,681
Dividends on common stock				0		0
Stockholders' equity, ending balance		$ 22,210	$ 26,259	$ 22,210		$ 26,259

[1] Represents 103,000 shares purchased in connection with employee tax withholding for restricted stock units vested under our Amended and Restated 1999 Equity Incentive Plan.

[2] Represents 123,000 shares purchased in connection with employee tax withholding for restricted stock units vested under our Amended and Restated 1999 Equity Incentive Plan.

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