Construction and Line Item Joint Ventures - Consolidated Construction Joint Ventures (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011		Dec. 31, 2010
Construction Joint Venture [Line Items]
Cash and cash equivalents	$ 287,322,000		$ 193,099,000		$ 287,322,000		$ 193,099,000		$ 256,990,000		$ 252,022,000
Other current assets	13,974,000		29,526,000		13,974,000		29,526,000		35,171,000
Total current assets	1,019,908,000		990,994,000		1,019,908,000		990,994,000		909,722,000
Other noncurrent assets	78,375,000		80,709,000		78,375,000		80,709,000		80,616,000
Total assets	1,598,635,000		1,618,469,000		1,598,635,000		1,618,469,000		1,547,799,000
Accounts payable	209,683,000		216,600,000		209,683,000		216,600,000		158,660,000
Billings in excess of costs and estimated earnings	91,348,000		89,505,000		91,348,000		89,505,000		90,845,000
Accrued expenses and other current liabilities	167,166,000		185,624,000		167,166,000		185,624,000		166,790,000
Total current liabilities	493,261,000		516,770,000		493,261,000		516,770,000		448,468,000
Construction	385,744,000		431,101,000		748,803,000		784,393,000
Net Cash Provided by (Used in) Operating Activities					20,163,000		2,018,000
Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	5				5
Partnership Interest [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	1,600,000,000				1,600,000,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Cash and cash equivalents	74,020,000	[1]	65,350,000	[1]	74,020,000	[1]	65,350,000	[1]	75,122,000	[1]
Other current assets	32,379,000		31,215,000		32,379,000		31,215,000		33,750,000
Total current assets	106,399,000		96,565,000		106,399,000		96,565,000		108,872,000
Other noncurrent assets	6,661,000		9,821,000		6,661,000		9,821,000		8,671,000
Total assets	113,060,000	[2]	106,386,000	[2]	113,060,000	[2]	106,386,000	[2]	117,543,000	[2]
Accounts payable	30,975,000		36,660,000		30,975,000		36,660,000		38,193,000
Billings in excess of costs and estimated earnings	13,955,000	[1]	17,116,000	[1]	13,955,000	[1]	17,116,000	[1]	22,251,000	[1]
Accrued expenses and other current liabilities	3,495,000		5,997,000		3,495,000		5,997,000		5,129,000
Total current liabilities	48,425,000		59,773,000		48,425,000		59,773,000		65,573,000
Noncurrent liabilities	0		33,000		0		33,000		4,000
Total liabilities	48,425,000	[2]	59,806,000	[2]	48,425,000	[2]	59,806,000	[2]	65,577,000	[2]
Number of Active Joint Venture Projects	2				2
Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	8				8
Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	600,000,000				600,000,000
Other Partners Interest in Partnerships [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	1,000,000,000				1,000,000,000
Minimum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	245,100,000				245,100,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	45.00%				45.00%
Construction	77,400,000		73,900,000		174,000,000		171,100,000
Net Cash Provided by (Used in) Operating Activities					16,100,000		6,000,000
Minimum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	59,400,000				59,400,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	20.00%				20.00%
Minimum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	42,000,000				42,000,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	400,000				400,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	21,900,000				21,900,000
Maximum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	334,300,000				334,300,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	60.00%				60.00%
Maximum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	1,200,000,000				1,200,000,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%				50.00%
Maximum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	133,200,000				133,200,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	186,600,000				186,600,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	$ 55,700,000				$ 55,700,000

[1] The volume and stage of completion of contracts from our consolidated construction joint ventures may cause fluctuations in cash and cash equivalents, as well as billings in excess of costs and estimated earnings between periods.

[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.