Subsequent Events (Details) (Subsequent events, USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Minimum
Subsequent Events
Expected incremental gross profit arising out of resolution with subcontractors	$ 1.0
Maximum
Subsequent Events
Expected incremental gross profit arising out of resolution with subcontractors	$ 1.6

Represents the amount of expected incremental gross profit arising out of resolution of remaining open issues with subcontractors.

No definition available.

Name:	fix_ExpectedIncrementalGrossProfitFromResolutionOfOpenIssuesWithSubcontractors
Namespace Prefix:	fix_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration