Income Taxes (Details)	9 Months Ended
	Sep. 30, 2013
Income Taxes
Effective tax rate on income before taxes and noncontrolling interests (as a percent)	38.13%
Effective tax rate for income attributable to Primoris (as a percent)	39.09%
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