Income Taxes (Details)	3 Months Ended
	Mar. 31, 2015
Income Taxes
Effective tax rate on income before provision for income taxes excluding income attributable to noncontrolling interests (as a percent)	38.69%
Effective tax rate for income attributable to Primoris (as a percent)	38.69%
U.S. federal statutory rate (as a percent)	35.00%
Minimum period of statute of limitations of state and foreign jurisdictions	3 years
Maximum period of statute of limitations of state and foreign jurisdictions	5 years