Construction and Line Item Joint Ventures - Consolidated Construction Joint Ventures (Details) (USD $)																				6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Dec. 31, 2009	Jun. 30, 2011 Minimum [Member] Joint Venture Consolidated [Member] Consolidated Construction Joint Venture [Member]	Jun. 30, 2011 Minimum [Member] Joint Venture Unconsolidated [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Minimum [Member] Joint Venture Unconsolidated [Member] Line Item Joint Venture [Member]	Jun. 30, 2011 Minimum [Member] Reporting Entitys Interest in Joint Venture [Member] Line Item Joint Venture [Member]	Jun. 30, 2011 Maximum [Member] Joint Venture Consolidated [Member] Consolidated Construction Joint Venture [Member]	Jun. 30, 2011 Maximum [Member] Joint Venture Unconsolidated [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Maximum [Member] Joint Venture Unconsolidated [Member] Line Item Joint Venture [Member]	Jun. 30, 2011 Maximum [Member] Reporting Entitys Interest in Joint Venture [Member] Line Item Joint Venture [Member]	Jun. 30, 2011 Partnership Interest [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Joint Venture Consolidated [Member] Consolidated Construction Joint Venture [Member]		Dec. 31, 2010 Joint Venture Consolidated [Member] Consolidated Construction Joint Venture [Member]		Jun. 30, 2010 Joint Venture Consolidated [Member] Consolidated Construction Joint Venture [Member]		Jun. 30, 2010 Joint Venture Consolidated [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Joint Venture Unconsolidated [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Reporting Entitys Interest in Joint Venture [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Other Partners Interest in Partnerships [Member] Unconsolidated Construction Joint Venture [Member]	Jun. 30, 2011 Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Joint Venture Increase in Assets From Consolidation																				$ 2,400,000
Joint Venture Increase in Liabilities From Consolidation																				1,700,000
Increase in noncontrolling interest from consolidation of joint venture																				800,000
Cash and cash equivalents	190,069,000	252,022,000	208,450,000	338,956,000										89,666,000		109,380,000		105,690,000
Other current assets	34,779,000	42,555,000	39,031,000											35,183,000	[1]	50,344,000	[1]	36,361,000	[1]
Total current assets	922,605,000	913,856,000	975,358,000											124,849,000		159,724,000		142,051,000
Noncurrent assets														11,012,000		2,561,000		829,000
Total assets	1,551,947,000	1,535,533,000	1,655,177,000											135,861,000	[2]	162,285,000	[2]	142,880,000	[2]
Accounts payable														37,229,000		33,078,000		32,145,000
Billings in excess of costs and estimated earnings	122,014,000	120,185,000	144,935,000											41,386,000		46,475,000		66,706,000
Accrued expenses and other current liabilities	156,727,000	150,773,000	161,632,000											9,147,000		11,633,000		11,125,000
Total current liabilities	483,210,000	438,777,000	528,399,000											87,762,000		91,186,000		109,976,000
Noncurrent liabilities														0		3,000		505,000
Total liabilities														87,762,000	[2]	91,189,000	[2]	110,481,000	[2]
Number of active consolidated construction joint venture projects														3							7			4
Remaining Construction Contract Value					$ 225,600,000	$ 57,600,000	$ 51,900,000	$ 21,000,000	$ 480,400,000	$ 975,400,000	$ 152,700,000	$ 70,000,000	$ 1,700,000,000									$ 600,000,000	$ 1,100,000,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly					45.00%	20.00%			60.00%	42.50%

[1] Prior period amounts have been revised to conform to current year presentation. The revisions had no impact on the consolidated balances or on the accounting for consolidated construction joint ventures.

[2] 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.