Dividends and Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	0 Months Ended				3 Months Ended
	Apr. 15, 2013	Mar. 05, 2013	Dec. 26, 2012	Nov. 02, 2012	Mar. 31, 2013	Mar. 31, 2012
Dividends and Earnings Per Share
Cash dividend declared (in dollars per share)		$ 0.03		$ 0.03
Total dividend paid	$ 1,547		$ 1,542			$ 1,532
Numerator:
Net income attributable to Primoris					$ 9,770	$ 10,486
Denominator:
Weighted average shares for computation of basic earnings per share					51,456	51,096
Dilutive effect of contingently issuable shares						233
Dilutive effect of shares issued to independent directors					9	8
Dilutive effect of shares to be issued to Q3C sellers					2
Weighted average shares for computation of diluted earnings per share					51,467	51,337
Earnings per share:
Basic earnings per share (in dollars per share)					$ 0.19	$ 0.21
Diluted earnings per share (in dollars per share)					$ 0.19	$ 0.20