Dividends and Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands							3 Months Ended
	Feb. 22, 2020	Oct. 31, 2019	Aug. 02, 2019	May 03, 2019	Feb. 26, 2019	Nov. 02, 2018	Mar. 31, 2020	Mar. 31, 2019
Dividends and Earnings Per Share
Cash dividend declared (in dollars per share)	$ 0.060	$ 0.060	$ 0.060	$ 0.060	$ 0.060	$ 0.060	$ 0.06	$ 0.06
Numerator:
Net (loss) income attributable to Primoris							$ (3,737)	$ 1,947
Denominator:
Weighted average shares for computation of basic earnings per share							48,588	50,770
Dilutive effect of shares issued to independent directors								8
Dilutive effect of restricted stock units								410
Weighted average shares for computation of diluted (loss) earnings per share							48,588	51,188
(loss) earnings per share attributable to Primoris:
Basic earnings per share (in dollars per share)							$ (0.08)	$ 0.04
Diluted earnings per share (in dollars per share)							$ (0.08)	$ 0.04