XML 33 R77.htm IDEA: XBRL DOCUMENT v2.4.1.9
Reportable Operating Segments (Details 2)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Revenues and total assets by geographic area      
% of Revenue 100.00%prim_RevenuePercentage 100.00%prim_RevenuePercentage 100.00%prim_RevenuePercentage
Non-United States      
Revenues and total assets by geographic area      
% of Revenue 1.00%prim_RevenuePercentage
/ us-gaap_StatementGeographicalAxis
= prim_NonUnitedStatesMember		    
% of total assets 1.00%prim_TotalAssetsPercentage
/ us-gaap_StatementGeographicalAxis
= prim_NonUnitedStatesMember