Construction Joint Ventures - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($) project	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) project	Sep. 30, 2017 USD ($)
Construction Joint Venture
Number of active construction joint venture projects | project	9		9
Construction Contract Value	$ 11,200,000		$ 11,200,000
Revenue	1,055,591	$ 957,126	2,426,089	$ 2,188,439
Net cash provided by operating activities			14,743	64,614
Unconsolidated Construction Joint Venture Net (Loss) Income	$ (47,600)	31,000	$ (162,000)	57,200
Line Item Joint Venture [Member]
Construction Joint Venture
Number of active construction joint venture projects | project	1		1
Revenue	$ 800	5,400	$ 2,000	20,100
Line Item Joint Venture One [Member]
Construction Joint Venture
Construction Contract Value	18,000		18,000
Minimum [Member]
Construction Joint Venture
Construction Contract Value	$ 85,200		$ 85,200
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	20.00%		20.00%
Maximum [Member]
Construction Joint Venture
Construction Contract Value	$ 3,800,000		$ 3,800,000
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%		50.00%
Reporting Entitys Interest in Joint Venture [Member]
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	$ 1,200,000		$ 1,200,000
Other Partners Interest in Partnerships [Member]
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	$ 2,300,000		$ 2,300,000
Joint Venture Consolidated [Member]
Construction Joint Venture
Number of active construction joint venture projects | project	6		6
Construction Contract Value	$ 1,200,000		$ 1,200,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture
Revenue	61,600	44,500	173,100	129,500
Net cash provided by operating activities			31,500	26,400
Joint Venture Consolidated [Member] | Minimum [Member]
Construction Joint Venture
Construction Contract Value	$ 50,800		$ 50,800
Joint Venture Consolidated [Member] | Minimum [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%		50.00%
Joint Venture Consolidated [Member] | Maximum [Member]
Construction Joint Venture
Construction Contract Value	$ 409,700		$ 409,700
Joint Venture Consolidated [Member] | Maximum [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	65.00%		65.00%
Partnership Interest [Member]
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	$ 3,500,000		$ 3,500,000
Granite Construction [Member]
Construction Joint Venture
Revenue			1,100,000
Unconsolidated Construction Joint Venture Net (Loss) Income	(3,100)	$ (7,100)	(16,500)	$ (15,300)
Granite Construction [Member] | Line Item Joint Venture One [Member]
Construction Joint Venture
Construction Contract Value	10,800		10,800
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	$ 9,900		9,900
Granite Construction [Member] | Minimum [Member]
Construction Joint Venture
Revenue			2,300
Granite Construction [Member] | Maximum [Member]
Construction Joint Venture
Revenue			273,200
Granite Construction [Member] | Joint Venture Consolidated [Member]
Construction Joint Venture
Revenue			394,900
Granite Construction [Member] | Joint Venture Consolidated [Member] | Minimum [Member]
Construction Joint Venture
Revenue			500
Granite Construction [Member] | Joint Venture Consolidated [Member] | Maximum [Member]
Construction Joint Venture
Revenue			$ 185,000