FAIR VALUE MEASUREMENTS (Recurring Fair Value Measurements) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Equity, Fair Value Disclosure [Abstract]
Employee housing loans	$ 3,162epam_PaymentsforLoansIssuedtoEmployees	$ 8,963epam_PaymentsforLoansIssuedtoEmployees
Proceeds from repayments of employee housing loans	3,025	3,088
Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	220,534	169,207
Time deposits and restricted cash	156	1,711
Total assets measured at fair value on recurring basis	227,205	177,308
Equity, Fair Value Disclosure [Abstract]
Contingent consideration	37,400
Performance-based equity awards	3,223
Total liabilities measured at fair value on a recurring basis	40,623
Fair Value, Measurements, Recurring \| Level 1
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	220,534	169,207
Time deposits and restricted cash	0	0
Total assets measured at fair value on recurring basis	220,534	169,207
Fair Value, Measurements, Recurring \| Level 2
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	0	0
Time deposits and restricted cash	156	1,711
Total assets measured at fair value on recurring basis	156	1,711
Fair Value, Measurements, Recurring \| Level 3
Assets, Fair Value Disclosure [Abstract]
Cash and cash equivalents	0	0
Time deposits and restricted cash	0	0
Total assets measured at fair value on recurring basis	6,515	6,390
Equity, Fair Value Disclosure [Abstract]
Contingent consideration	37,400
Performance-based equity awards	3,223
Total liabilities measured at fair value on a recurring basis	40,623
Fair Value, Measurements, Nonrecurring
Assets, Fair Value Disclosure [Abstract]
Employee loans	6,515	6,390
Fair Value, Measurements, Nonrecurring \| Level 1
Assets, Fair Value Disclosure [Abstract]
Employee loans	0	0
Fair Value, Measurements, Nonrecurring \| Level 2
Assets, Fair Value Disclosure [Abstract]
Employee loans	0	0
Fair Value, Measurements, Nonrecurring \| Level 3
Assets, Fair Value Disclosure [Abstract]
Employee loans	$ 6,515	$ 6,390

Contingent Consideration Classified As Liability, Fair Value Disclosure

No definition available.

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Payments for Loans Issued to Employees

+ References

No definition available.

+ Details

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- Definition

Proceeds from Collection of Loans to Employees

+ References

No definition available.

+ Details

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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- Definition

Fair value of the entity's equity.

+ References

+ Details

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- Details

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- Definition

Fair value of equity issued in a business combination.

+ References

+ Details

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- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Glossary Loan

-URI http://asc.fasb.org/extlink&oid=6517073

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- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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