Construction and Line Item Joint Ventures - Consolidated Construction Joint Ventures (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010	Dec. 31, 2009
Construction Joint Venture [Line Items]
Cash and cash equivalents	$ 321,990,000		$ 256,990,000		$ 252,022,000	$ 338,956,000
Other current assets	31,834,000		35,171,000
Total current assets	1,022,057,000		909,722,000
Total assets	1,729,487,000		1,547,799,000		1,535,533,000
Accounts payable	202,541,000		158,660,000
Billings in excess of costs and estimated earnings	139,692,000		90,845,000
Accrued expenses and other current liabilities	169,979,000		166,790,000
Total current liabilities	531,272,000		448,468,000
Contracts Revenue	984,106,000		1,043,614,000		943,245,000
Net Cash Provided by (Used in) Operating Activities	91,790,000		92,345,000		29,318,000
Partnership Interest [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	1,600,000,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Cash and cash equivalents	105,865,000		75,122,000
Other current assets	47,910,000		33,750,000
Total current assets	153,775,000		108,872,000
Noncurrent assets	42,814,000		8,671,000
Total assets	196,589,000	[1]	117,543,000	[1]
Accounts payable	34,536,000		38,193,000
Billings in excess of costs and estimated earnings	72,490,000		22,251,000
Accrued expenses and other current liabilities	8,312,000		5,129,000
Total current liabilities	115,338,000		65,573,000
Noncurrent liabilities	0		4,000
Total liabilities	115,338,000	[1]	65,577,000	[1]
Number of active construction joint venture projects	4
Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of active construction joint venture projects	10
Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of active construction joint venture projects	5
Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	553,800,000
Other Partners Interest in Partnerships [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	1,100,000,000
Minimum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	5,800,000
Contracts Revenue	222,300,000		233,000,000		225,700,000
Net Cash Provided by (Used in) Operating Activities	25,200,000		21,600,000		(300,000)
Minimum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	59,400,000
Minimum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	42,000,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Proportionate Share of the Consolidated and Unconsolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	45.00%
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Proportionate Share of the Consolidated and Unconsolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	20.00%
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	21,900,000
Maximum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	334,700,000
Maximum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	1,200,000,000
Maximum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	133,400,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Proportionate Share of the Consolidated and Unconsolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	65.00%
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Proportionate Share of the Consolidated and Unconsolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	$ 58,000,000

[1] The assets and liabilities of each joint venture relate solely to that joint venture. The decision to distribute joint venture cash and cash equivalents and assets must generally be made jointly by all of the partners and, accordingly, these cash and cash equivalents and assets generally are not available for the working capital needs of Granite.