Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Earnings Per Share, Basic, Two Class Method [Abstract]
Net loss attributable to Granite, Earnings Per Share, Basic	$ (11,773)	$ (9,007)
Weighted Average Number of Shares Outstanding, Basic	38,265	37,963
Net income (loss) per share, basic	$ (0.31)	$ (0.24)
Earnings Per Share, Diluted, Two Class Method [Abstract]
Net loss attributable to Grainte, Earnings per Share, Diluted	$ (11,773)	$ (9,007)
Weighted average common shares outstanding, diluted	38,265	37,963
Net income (loss) per share, diluted	$ (0.31)	$ (0.24)