Legal Proceedings	12 Months Ended
Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	Legal Proceedings In the ordinary course of business, we and our affiliates are involved in various legal proceedings alleging, among other things, public liability issues or breach of contract or tortious conduct in connection with the performance of services and/or materials provided, the various outcomes of which cannot be predicted with certainty. We and our affiliates are also subject to government inquiries in the ordinary course of business seeking information concerning our compliance with government construction contracting requirements and various laws and regulations, the outcomes of which cannot be predicted with certainty. Some of the matters in which we or our joint ventures and affiliates are involved may involve compensatory, punitive, or other claims or sanctions that, if granted, could require us to pay damages or make other expenditures in amounts that are not probable to be incurred or cannot currently be reasonably estimated. In addition, in some circumstances our government contracts could be terminated, we could be suspended, debarred or incur other administrative penalties or sanctions, or payment of our costs could be disallowed. While any of our pending legal proceedings may be subject to early resolution as a result of our ongoing efforts to settle, whether or when any legal proceeding will be resolved through settlement is neither predictable nor guaranteed. Accordingly, it is possible that future developments in such proceedings and inquiries could require us to (i) adjust existing accruals, or (ii) record new accruals that we did not originally believe to be probable or that could not be reasonably estimated. Such changes could be material to our financial condition, results of operations and/or cash flows in any particular reporting period. In addition to matters that are considered probable for which the loss can be reasonably estimated, we also disclose certain matters where the loss is considered reasonably possible and is reasonably estimable. Liabilities relating to legal proceedings and government inquiries, to the extent that we have concluded such liabilities are probable and the amounts of such liabilities are reasonably estimable, are recorded on the consolidated balance sheets. The aggregate liabilities recorded as of December 31, 2015 and 2014 related to these matters were approximately $5.2 million and $9.7 million, respectively, and were primarily included in accrued expenses and other current liabilities. The aggregate range of possible loss related to (i) matters considered reasonably possible, and (ii) reasonably possible amounts in excess of accrued losses recorded for probable loss contingencies, was immaterial as of December 31, 2015. Our view as to such matters could change in future periods. Investigation Related to Grand Avenue Project Disadvantaged Business Enterprise (“DBE”) Issues: On March 6, 2009, the U.S. Department of Transportation, Office of Inspector General served upon our wholly-owned subsidiary, Granite Construction Northeast, Inc. (“Granite Northeast”), a United States District Court, Eastern District of New York Grand Jury subpoena to produce documents. The subpoena sought all documents pertaining to the use of a DBE firm (the “Subcontractor”), and the Subcontractor’s use of a non-DBE subcontractor/consultant, on the Grand Avenue Bus Depot and Central Maintenance Facility for the Borough of Queens Project (the “Grand Avenue Project”), a Granite Northeast project, that began in 2004 and was substantially complete in 2008. The subpoena also sought any documents regarding the use of the Subcontractor as a DBE on any other projects and any other documents related to the Subcontractor or to the subcontractor/consultant. Granite Northeast produced the requested documents, together with other requested information. Subsequently, Granite Northeast was informed by the Department of Justice (“DOJ”) that it was a subject of an investigation, along with others, and that the DOJ believed that Granite Northeast’s claim of DBE credit for the Subcontractor was improper. In addition to the documents produced in response to the Grand Jury subpoena, Granite Northeast provided the requested information to the DOJ, along with other federal and state agencies (collectively the “Agencies”), concerning other DBE entities for which Granite Northeast historically claimed DBE credit. The matter was settled with the Agencies on November 24, 2015. Granite, Granite Northeast and the DOJ entered into a Non-Prosecution Agreement where Granite Northeast agreed to make payments totaling $8.25 million. A total of $3.5 million was paid in 2015 ($2.5 million to the DOJ, and $1.0 million to the Metropolitan Transportation Authority (“MTA”)). A final payment totaling $4.75 million will be made to the DOJ in 2016 (none to MTA in 2016) is included in accrued and other current liabilities on our consolidated balance sheets as of December 31, 2015. The Non-Prosecution Agreement contains certain ongoing compliance requirements for Granite and failure to comply with these terms could lead to civil or criminal remedies.

Legal Proceedings

In the ordinary course of business, we and our affiliates are involved in various legal proceedings alleging, among other things, public liability issues or breach of contract or tortious conduct in connection with the performance of services and/or materials provided, the various outcomes of which cannot be predicted with certainty. We and our affiliates are also subject to government inquiries in the ordinary course of business seeking information concerning our compliance with government construction contracting requirements and various laws and regulations, the outcomes of which cannot be predicted with certainty.

Some of the matters in which we or our joint ventures and affiliates are involved may involve compensatory, punitive, or other claims or sanctions that, if granted, could require us to pay damages or make other expenditures in amounts that are not probable to be incurred or cannot currently be reasonably estimated. In addition, in some circumstances our government contracts could be terminated, we could be suspended, debarred or incur other administrative penalties or sanctions, or payment of our costs could be disallowed. While any of our pending legal proceedings may be subject to early resolution as a result of our ongoing efforts to settle, whether or when any legal proceeding will be resolved through settlement is neither predictable nor guaranteed.

Accordingly, it is possible that future developments in such proceedings and inquiries could require us to (i) adjust existing accruals, or (ii) record new accruals that we did not originally believe to be probable or that could not be reasonably estimated. Such changes could be material to our financial condition, results of operations and/or cash flows in any particular reporting period. In addition to matters that are considered probable for which the loss can be reasonably estimated, we also disclose certain matters where the loss is considered reasonably possible and is reasonably estimable.

Liabilities relating to legal proceedings and government inquiries, to the extent that we have concluded such liabilities are probable and the amounts of such liabilities are reasonably estimable, are recorded on the consolidated balance sheets. The aggregate liabilities recorded as of December 31, 2015 and 2014 related to these matters were approximately $5.2 million and $9.7 million, respectively, and were primarily included in accrued expenses and other current liabilities. The aggregate range of possible loss related to (i) matters considered reasonably possible, and (ii) reasonably possible amounts in excess of accrued losses recorded for probable loss contingencies, was immaterial as of December 31, 2015. Our view as to such matters could change in future periods.

Investigation Related to Grand Avenue Project Disadvantaged Business Enterprise (“DBE”) Issues: On March 6, 2009, the U.S. Department of Transportation, Office of Inspector General served upon our wholly-owned subsidiary, Granite Construction Northeast, Inc. (“Granite Northeast”), a United States District Court, Eastern District of New York Grand Jury subpoena to produce documents. The subpoena sought all documents pertaining to the use of a DBE firm (the “Subcontractor”), and the Subcontractor’s use of a non-DBE subcontractor/consultant, on the Grand Avenue Bus Depot and Central Maintenance Facility for the Borough of Queens Project (the “Grand Avenue Project”), a Granite Northeast project, that began in 2004 and was substantially complete in 2008. The subpoena also sought any documents regarding the use of the Subcontractor as a DBE on any other projects and any other documents related to the Subcontractor or to the subcontractor/consultant. Granite Northeast produced the requested documents, together with other requested information. Subsequently, Granite Northeast was informed by the Department of Justice (“DOJ”) that it was a subject of an investigation, along with others, and that the DOJ believed that Granite Northeast’s claim of DBE credit for the Subcontractor was improper. In addition to the documents produced in response to the Grand Jury subpoena, Granite Northeast provided the requested information to the DOJ, along with other federal and state agencies (collectively the “Agencies”), concerning other DBE entities for which Granite Northeast historically claimed DBE credit. The matter was settled with the Agencies on November 24, 2015. Granite, Granite Northeast and the DOJ entered into a Non-Prosecution Agreement where Granite Northeast agreed to make payments totaling $8.25 million. A total of $3.5 million was paid in 2015 ($2.5 million to the DOJ, and $1.0 million to the Metropolitan Transportation Authority (“MTA”)). A final payment totaling $4.75 million will be made to the DOJ in 2016 (none to MTA in 2016) is included in accrued and other current liabilities on our consolidated balance sheets as of December 31, 2015. The Non-Prosecution Agreement contains certain ongoing compliance requirements for Granite and failure to comply with these terms could lead to civil or criminal remedies.