Construction and Line Item Joint Ventures - Unconsolidated Construction Joint Ventures (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 project		Dec. 31, 2013		Dec. 31, 2012
Construction Joint Venture [Line Items]
Equity in Construction Joint Ventures Current Assets Excluding Deficit in Equity	$ 184,575,000		$ 162,673,000
Partnership Interest [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	5,700,000,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of active construction joint venture projects	3
Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Net Income	116,800,000		283,200,000		256,900,000
Number of active construction joint venture projects	10
Cash and cash equivalents	264,263,000	[1]	385,094,000	[1]
Other assets	573,898,000		523,827,000
Accounts payable	146,198,000		155,985,000
Billings in excess of costs and estimated earnings	156,604,000	[1]	245,341,000	[1]
Other liabilities	55,289,000		104,152,000
Revenue	1,501,894,000		1,391,190,000		1,042,209,000
Cost of revenue	1,386,577,000		1,107,533,000		785,079,000
Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of active construction joint venture projects	3
Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	1,700,000,000
Interest in assets	291,254,000		296,391,000
Interest in liabilities	106,679,000		133,718,000
Revenue	453,380,000		408,456,000		376,427,000
Cost of revenue	402,515,000		334,863,000		273,239,000
Granite's interest in gross profit	50,865,000		73,593,000		103,188,000
Other Partners Interest in Partnerships [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	4,000,000,000
Interest in assets	546,907,000		612,530,000
Interest in liabilities	251,412,000		371,760,000
Revenue	1,048,514,000	[2]	982,734,000	[2]	665,782,000	[2]
Cost of revenue	984,062,000	[2]	772,670,000	[2]	511,840,000	[2]
Parent Company [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Net Income	49,200,000		72,800,000		101,700,000
Minimum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	32,700,000
Minimum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	72,800,000
Minimum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	42,700,000
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	55.00%
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%
Revenue Per Project Remaining to be Recognized on Unconsolidated and Line Item Construction Joint Ventures	10,700,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	28,900,000
Revenue Per Project Remaining to be Recognized on Unconsolidated and Line Item Construction Joint Ventures	2,300,000
Maximum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	364,400,000
Maximum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	3,100,000,000
Maximum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	86,000,000
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%
Revenue Per Project Remaining to be Recognized on Unconsolidated and Line Item Construction Joint Ventures	683,800,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Total Construction Contract Value	63,600,000
Revenue Per Project Remaining to be Recognized on Unconsolidated and Line Item Construction Joint Ventures	$ 23,400,000

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

[2] Partners’ interest represents amounts to reconcile total revenue and total cost of revenue as reported by our partners to Granite’s interest adjusted to reflect our accounting policies.