CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Total Granite Shareholders' Equity [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2009	$ 882,556	$ 830,651	$ 386	$ 94,633	$ 735,632	$ 51,905
Beginning Balance (in shares) at Dec. 31, 2009			38,635,021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(62,448)	(58,983)	0	0	(58,983)	(3,465)
Restricted stock and stock issued for services (in 2010 and 2011) / Stock units vested for services (in 2012), net of forfeitures	1,005	1,005	2	1,003	0	0
Restricted stock and stock issued for services (in 2010 and 2011) / Stock units vested for services (in 2012), net of forfeitures (in shares)			214,128
Amortized restricted stock	13,040	13,040	0	13,040	0	0
Purchase of common stock	(3,641)	(3,641)	(1)	(3,640)	0	0
Purchase of common stock (in shares)			(132,093)
Cash dividends on common stock	(20,165)	(20,165)	0	0	(20,165)	0
Net tax on stock-based compensation	(815)	(815)	0	(815)	0	0
Transactions with noncontrolling interests, net	(13,836)	0	0	0	0	(13,836)
Stock options exercised and other	(61)	(61)	0	11	(72)	0
Stock options exercised and other (in shares)			28,486
Ending Balance at Dec. 31, 2010	795,635	761,031	387	104,232	656,412	34,604
Ending Balance (in shares) at Dec. 31, 2010			38,745,542
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	66,085	51,161	0	0	51,161	14,924
Restricted stock and stock issued for services (in 2010 and 2011) / Stock units vested for services (in 2012), net of forfeitures	0	0	1	(1)	0	0
Restricted stock and stock issued for services (in 2010 and 2011) / Stock units vested for services (in 2012), net of forfeitures (in shares)			80,245
Amortized restricted stock	12,155	12,155	0	12,155	0	0
Purchase of common stock	(4,029)	(4,029)	(1)	(4,028)	0	0
Purchase of common stock (in shares)			(143,527)
Cash dividends on common stock	(20,107)	(20,107)	0	0	(20,107)	0
Net tax on stock-based compensation	(1,360)	(1,360)	0	(1,360)	0	0
Transactions with noncontrolling interests, net	(21,062)	0	0	0	0	(21,062)
Stock options exercised and other	346	346	0	516	(170)	0
Stock options exercised and other (in shares)			511
Ending Balance at Dec. 31, 2011	827,663	799,197	387	111,514	687,296	28,466
Ending Balance (in shares) at Dec. 31, 2011	38,682,771		38,682,771
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	59,920	45,283	0	0	45,283	14,637
Restricted stock and stock issued for services (in 2010 and 2011) / Stock units vested for services (in 2012), net of forfeitures	1	1	2	(1)	0	0
Restricted stock and stock issued for services (in 2010 and 2011) / Stock units vested for services (in 2012), net of forfeitures (in shares)			191,285
Amortized restricted stock	11,475	11,475	0	11,475	0	0
Purchase of common stock	(4,854)	(4,854)	(2)	(4,852)	0	0
Purchase of common stock (in shares)			(161,080)
Cash dividends on common stock	(20,117)	(20,117)	0	0	(20,117)	0
Net tax on stock-based compensation	(1,573)	(1,573)	0	(1,573)	0	0
Transactions with noncontrolling interests, net	(15,986)	0	0	0	0	(15,986)
Stock options exercised and other	541	541	0	859	(318)	0
Stock options exercised and other (in shares)			17,689
Ending Balance at Dec. 31, 2012	$ 871,858	$ 829,953	$ 387	$ 117,422	$ 712,144	$ 41,905
Ending Balance (in shares) at Dec. 31, 2012	38,730,665		38,730,665