Quarterly Financial Data (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Financial Data [Abstract]
Revenue, Net	$ 539,548	$ 728,578	$ 484,674	$ 256,731	$ 417,228	$ 670,850	$ 454,204	$ 220,683	$ 2,009,531	$ 1,762,965	$ 1,963,479
Gross profit	79,126	93,893	44,956	29,988	46,217	76,155	49,698	5,714	247,963	177,784	349,509
Gross profit as a percent of revenue	14.70%	12.90%	9.30%	11.70%	11.10%	11.40%	10.90%	2.60%
Net income (loss)	24,792	42,376	6,173	(7,256)	(65,386)	43,301	(2,633)	(37,730)	66,085	(62,448)	100,201
Net income (loss) as a percent of revenue	4.60%	5.80%	1.30%	(2.80%)	(15.70%)	6.50%	(0.60%)	(17.10%)
Net income (loss) attributable to Granite	18,754	36,468	4,946	(9,007)	(50,019)	38,681	(6,691)	(40,954)	51,161	(58,983)	73,500
Net income (loss) attributable to Granite as a percent of revenue	3.50%	5.00%	1.00%	(3.50%)	(12.00%)	5.80%	(1.50%)	(18.60%)
Net (loss) income per share attributable to common shareholders:
Basic (in dollars per share)	$ 0.48	$ 0.94	$ 0.13	$ (0.24)	$ (1.32)	$ 1.00	$ (0.18)	$ (1.09)	$ 1.32	$ (1.56)	$ 1.91
Diluted (in dollars per share)	$ 0.48	$ 0.93	$ 0.13	$ (0.24)	$ (1.32)	$ 0.99	$ (0.18)	$ (1.09)	$ 1.31	$ (1.56)	$ 1.90
Restructuring charges					$ 107,300				$ 2,181	$ 109,279	$ 9,453