Name:	prim_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesPeriod
Namespace Prefix:	prim_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the contingent consideration credited to non-operating income upon not meeting earnout target in a business combination.

No definition available.

Name:	prim_BusinessCombinationContingentConsiderationCreditedToNonOperatingIncomeUponNotMeetingEarnoutTarget
Namespace Prefix:	prim_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the information pertaining to performance target periods.

No definition available.

Name:	prim_PerformanceTargetTerm
Namespace Prefix:	prim_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_BusinessAcquisitionContingentConsiderationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsRangeOfOutcomesValueHigh
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of liability recognized arising from contingent consideration in a business combination.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 35
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6911338&loc=d3e6819-128478

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

Name:	us-gaap_BusinessCombinationContingentConsiderationLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Name:	us-gaap_BusinessAcquisitionAxis=prim_Q3ContractingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=prim_BusinessCombinationContingentConsiderationEarnoutTarget2014Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=prim_BusinessCombinationContingentConsiderationEarnoutTarget2013Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_BusinessAcquisitionAxis=prim_VadnaisCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=prim_BusinessCombinationContingentConsiderationEarnoutTarget2015Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=prim_BusinessCombinationContingentConsiderationEarnoutTarget2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_BusinessAcquisitionAxis=prim_SurberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=prim_BusinessCombinationContingentConsiderationEarnoutTargetPeriodOf2014Through2016Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: