Construction and Line Item Joint Ventures - Consolidated Construction Joint Ventures (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012		Dec. 31, 2011
Construction Joint Venture [Line Items]
Cash and cash equivalents	$ 247,833,000		$ 237,951,000		$ 247,833,000		$ 237,951,000		$ 321,990,000		$ 256,990,000
Other current assets	35,651,000		20,436,000		35,651,000		20,436,000		31,834,000
Total current assets	1,009,530,000		915,159,000		1,009,530,000		915,159,000		1,022,057,000
Property and equipment, net	471,265,000		439,664,000		471,265,000		439,664,000		481,478,000
Other noncurrent assets	80,365,000		68,603,000		80,365,000		68,603,000		84,392,000
Total assets	1,701,404,000		1,507,647,000		1,701,404,000		1,507,647,000		1,729,487,000
Accounts payable	188,124,000		186,290,000		188,124,000		186,290,000		202,541,000
Billings in excess of costs and estimated earnings	144,044,000		75,629,000		144,044,000		75,629,000		139,692,000
Accrued expenses and other current liabilities	200,521,000		155,322,000		200,521,000		155,322,000		169,979,000
Total current liabilities	534,856,000		442,671,000		534,856,000		442,671,000		531,272,000
Construction	308,602,000		245,113,000		485,720,000		363,059,000
Net Cash Provided by (Used in) Operating Activities					(51,648,000)		(34,624,000)
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	5,100,000,000				5,100,000,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Cash and cash equivalents	63,806,000	[1]	67,685,000	[1]	63,806,000	[1]	67,685,000	[1]	105,865,000	[1]
Receivables, Net, Current	59,807,000		26,903,000		59,807,000		26,903,000		43,902,000
Other current assets	3,592,000		2,125,000		3,592,000		2,125,000		4,008,000
Property and equipment, net	34,891,000		6,919,000		34,891,000		6,919,000		41,114,000
Other noncurrent assets	1,253,000		0		1,253,000		0		1,700,000
Total assets	163,349,000	[2]	103,632,000	[2]	163,349,000	[2]	103,632,000	[2]	196,589,000	[2]
Accounts payable	18,297,000		31,135,000		18,297,000		31,135,000		34,536,000
Billings in excess of costs and estimated earnings	72,094,000	[1]	17,979,000	[1]	72,094,000	[1]	17,979,000	[1]	72,490,000	[1]
Accrued expenses and other current liabilities	9,153,000		3,027,000		9,153,000		3,027,000		8,312,000
Total liabilities	99,544,000	[2]	52,141,000	[2]	99,544,000	[2]	52,141,000	[2]	115,338,000	[2]
Number of Active Joint Venture Projects	4				4
Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	12				12
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	1,400,000,000				1,400,000,000
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	3,700,000,000				3,700,000,000
Minimum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	400,000				400,000
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	400,000				400,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	51.00%				51.00%
Construction	45,500,000		55,000,000		88,700,000		96,600,000
Net Cash Provided by (Used in) Operating Activities					(16,300,000)		(1,900,000)
Minimum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	40,300,000				40,300,000
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	42,200,000				42,200,000
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	300,000				300,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	25,100,000				25,100,000
Maximum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	336,900,000				336,900,000
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	120,500,000				120,500,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	65.00%				65.00%
Maximum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	3,100,000,000				3,100,000,000
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	138,200,000				138,200,000
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	722,900,000				722,900,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	$ 59,500,000				$ 59,500,000

[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 until distributed.