Contract Receivables (Details Textual)	3 Months Ended
Mar. 31, 2013
Contract Receivables (Textual) [Abstract]
Majority of unbilled receivables will be substantially billed and collected	1 year

Majority of unbilled receivables will be substantially billed and collected.

No definition available.

Name:	icfi_MajorityOfUnbilledReceivablesWillBeSubstantiallyBilledAndCollected
Namespace Prefix:	icfi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration