CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF INCOME
Revenue	$ 2,379,995	$ 1,996,948	$ 1,929,415
Cost of revenue	2,101,561	1,795,641	1,709,542
Gross profit	278,434	201,307	219,873
Selling, general and administrative expenses	172,146	140,842	151,703
Impairment of goodwill	0	2,716	401
Operating income	106,288	57,749	67,769
Other income (expense):
Investment income	5,817
Foreign exchange gain (loss)	253	202	(763)
Other income (expense), net	484	(315)	1,723
Interest income	587	149	56
Interest expense	(8,146)	(8,914)	(7,688)
Income before provision for income taxes	105,283	48,871	61,097
Provision for income taxes	(28,433)	(21,146)	(23,946)
Net income	76,850	27,725	37,151
Less net income attributable to noncontrolling interests	(4,496)	(1,002)	(279)
Net income attributable to Primoris	$ 72,354	$ 26,723	$ 36,872
Dividends per common share (in dollars per share)	$ 0.225	$ 0.220	$ 0.205
Earnings per share:
Basic (in dollars per share)	1.41	0.52	0.71
Diluted (in dollars per share)	$ 1.40	$ 0.51	$ 0.71
Weighted average common shares outstanding:
Basic (in shares)	51,481	51,762	51,647
Diluted (in shares)	51,741	51,989	51,798