Construction and Line Item Joint Ventures - Consolidated Construction Joint Ventures (Details) (USD $)	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012		Dec. 31, 2011
Construction Joint Venture [Line Items]
Cash and cash equivalents	$ 260,773,000		$ 226,226,000		$ 321,990,000		$ 256,990,000
Other current assets	37,401,000		34,882,000		31,834,000
Total current assets	976,220,000		846,888,000		1,022,057,000
Other noncurrent assets	82,531,000		69,949,000		84,392,000
Total assets	1,678,710,000		1,469,955,000		1,729,487,000
Accounts payable	169,940,000		129,480,000		202,541,000
Billings in excess of costs and estimated earnings	124,609,000		87,370,000		139,692,000
Accrued expenses and other current liabilities	188,685,000		148,196,000		169,979,000
Total current liabilities	495,719,000		393,913,000		531,272,000
Construction	177,119,000		117,946,000
Net Cash Provided by (Used in) Operating Activities	(54,653,000)		(22,873,000)
Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	4
Partnership Interest [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	4,500,000,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Cash and cash equivalents	98,738,000	[1]	69,423,000	[1]	105,865,000	[1]
Other current assets	50,907,000		40,410,000		47,910,000
Total current assets	149,645,000		109,833,000		153,775,000
Other noncurrent assets	39,486,000		7,516,000		42,814,000
Total assets	189,131,000	[2]	117,349,000	[2]	196,589,000	[2]
Accounts payable	26,354,000		28,591,000		34,536,000
Billings in excess of costs and estimated earnings	71,821,000	[1]	24,827,000	[1]	72,490,000	[1]
Accrued expenses and other current liabilities	8,983,000		5,640,000		8,312,000
Total current liabilities	107,158,000		59,058,000		115,338,000
Noncurrent liabilities	0		28,000		0
Total liabilities	107,158,000	[2]	59,086,000	[2]	115,338,000	[2]
Number of Active Joint Venture Projects	4
Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	10
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	1,200,000,000
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	3,300,000,000
Minimum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	9,500,000
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	4,000,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	45.00%
Construction	18,300,000		19,700,000
Net Cash Provided by (Used in) Operating Activities	6,600,000		5,400,000
Minimum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	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%
Minimum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	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	300,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	23,100,000
Maximum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	335,000,000
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	133,300,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	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
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%
Maximum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	134,600,000
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	732,800,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	$ 58,600,000

[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.