Deferred compensation on performance bonuses that eligible employee percentage.

No definition available.

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Data Type:	num:percentItemType
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- Details

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- Details

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- Definition

Maximum defer of compensation subject to statutory limitations percentage.

+ References

No definition available.

+ Details

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Namespace Prefix:	icfi_
Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Percentage of employee entitled to employer matching contribution condition one.

+ References

No definition available.

+ Details

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Namespace Prefix:	icfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employee entitled to employer matching contribution condition two.

+ References

No definition available.

+ Details

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Namespace Prefix:	icfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contributions condition one.

+ References

No definition available.

+ Details

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Namespace Prefix:	icfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of employer matching contributions condition two.

+ References

No definition available.

+ Details

Name:	icfi_PercentageOfEmployerMatchingContributionsConditionTwo
Namespace Prefix:	icfi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Commitment made to pay deferred cash remuneration expressed as a percentage of the individual's base salary.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationArrangementWithIndividualCashAwardsGrantedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

The discount rate from market value on purchase date that participants pay for shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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Data Type:	num:percentItemType
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Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Employee Benefit Plans (Additional Textual) [Abstract]
Percentage of compensation subject to statutory limitations	70.00%
Percentage of employer matching contributions, Condition 1	100.00%
Percentage of employer matching contributions, Condition 2	50.00%
Percentage of employee entitled to employer matching contribution, Condition 1	3.00%
Percentage of employee entitled to employer matching contribution, Condition 2	2.00%
Retirement Savings Plan [Member]
Employee Benefit Plans (Textual) [Abstract]
Contribution expense	$ 11.8	$ 10.3	$ 9.2
Deferred Compensation Plan [Member]
Employee Benefit Plans (Textual) [Abstract]
Percentage of base salary that eligible employee elect to defer	80.00%
Percentage of performance bonuses that eligible employee elect to defer	100.00%
Percentage of participants vested in their account balances	100.00%
Employee Stock Purchase Plan [Member] \| Maximum [Member]
Employee Benefit Plans (Textual) [Abstract]
Eligible employees to purchase shares of the Company's stock at a discount	5.00%