EPAM Systems (EPAM) 10-K 2 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 24, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	EPAM Systems, Inc.
Entity Central Index Key	1352010
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		48,858,032
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Document Period End Date	31-Dec-14
Document Type	10-K
Amendment Flag	FALSE
Entity Public Float			$1,589

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets
Cash and cash equivalents	$220,534	$169,207
Accounts receivable, net of allowance of $2,181 and $1,800, respectively	124,483	95,431
Unbilled revenues	55,851	43,108
Prepaid and other current assets	9,289	14,355
Employee loans, net of allowance of $0 and $0, respectively, current	2,434	1,989
Time deposits	0	1,188
Restricted cash, current	0	298
Deferred tax assets, current	2,496	5,392
Total current assets	415,087	330,968
Property and equipment, net	55,134	53,315
Restricted cash, long-term	156	225
Employee loans, net of allowance of $0 and $0, respectively, long-term	4,081	4,401
Intangible assets, net	47,689	13,734
Goodwill	57,417	22,268
Deferred tax assets, long-term	11,094	4,557
Other long-term assets	3,368	3,409
Total assets	594,026	432,877
Current liabilities
Accounts payable	4,641	2,835
Accrued expenses and other liabilities	32,203	20,175
Deferred revenue, current	3,220	4,543
Due to employees	24,518	12,665
Taxes payable	24,704	14,171
Contingent consideration, current (Note 2 and 17)	35,524	0
Deferred tax liabilities, current	603	275
Total current liabilities	125,413	54,664
Deferred revenue, long-term	0	533
Taxes payable, long-term	0	1,228
Deferred tax liabilities, long-term	4,563	351
Total liabilities	129,976	56,776
Commitments and contingencies (Note 16)
Stockholders’ equity
Common stock, $0.001 par value; 160,000,000 authorized; 48,748,298 and 47,569,463 shares issued, 48,303,811 and 46,614,916 shares outstanding at December 31, 2014 and December 31, 2013, respectively	48	46
Additional paid-in capital	229,501	195,585
Retained earnings	260,598	190,986
Treasury stock	-4,043	-8,684
Accumulated other comprehensive loss	-22,054	-1,832
Total stockholders’ equity	464,050	376,101
Total liabilities and stockholders’ equity	$594,026	$432,877

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Current assets
Accounts receivable allowance	$2,181	$1,800
Employee loans current allowance	0	0
Noncurrent assets
Employee loans long-term allowance	$0	$0
Stockholders' equity
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	160,000,000	160,000,000
Common stock, shares issued	48,748,298	47,569,463
Common stock, shares outstanding	48,303,811	46,614,916

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Revenues	$730,027	$555,117	$433,799
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	456,530	347,650	270,361
Selling, general and administrative expenses	163,666	116,497	85,868
Depreciation and amortization expense	17,483	15,120	10,882
Goodwill impairment loss	2,241	0	0
Other operating expenses/(income), net	3,924	-643	682
Income from operations	86,183	76,493	66,006
Interest and other income, net	4,769	3,077	1,941
Change in fair value of contingent consideration	-1,924	0	0
Foreign exchange loss	-2,075	-2,800	-2,084
Income before provision for income taxes	86,953	76,770	65,863
Provision for income taxes	17,312	14,776	11,379
Net income	69,641	61,994	54,484
Foreign currency translation adjustments	-20,251	-811	2,493
Comprehensive income	49,390	61,183	56,977
Net income allocated to participating securities	0	0	-3,341
Numerator for basic earnings per share	$69,641	$61,994	$51,143
Net income per share:
Basic (in dollars per share)	$1.48	$1.35	$1.27
Diluted (in dollars per share)	$1.40	$1.28	$1.17
Shares used in calculation of net income per share:
Basic (in shares)	47,189	45,754	40,190
Diluted (in shares)	49,734	48,358	43,821

CONSOLIDATED_STATEMENTS_OF_CHA

CONSOLIDATED STATEMENTS OF CHANGES IN REDEEMABLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (USD $)	Total	Instant Information Inc	Thoughtcorp Inc	Netsoft	Jointech	GGA	Great Fridays	Preferred Stock	Preferred Stock	Common Stock	Common Stock	Common Stock	Common Stock	Common Stock	Common Stock	Common Stock	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Treasury Stock	Treasury Stock	Treasury Stock	Treasury Stock	Treasury Stock	Treasury Stock	Accumulated Other Comprehensive Income
In Thousands, except Share data, unless otherwise specified	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	Series A-1 and A-2, Convertible Redeemable Preferred Stock	Series A-3 Convertible Preferred Stock	USD ($)	Instant Information Inc	Thoughtcorp Inc	Empathy Lab, LLC	Netsoft	Jointech	GGA	Great Fridays	USD ($)	Instant Information Inc	Thoughtcorp Inc	Empathy Lab, LLC	Netsoft	Jointech	GGA	Great Fridays	USD ($)	USD ($)	Thoughtcorp Inc	Empathy Lab, LLC	Netsoft	Jointech	GGA	Great Fridays	USD ($)
								USD ($)	USD ($)										USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)			USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)
Balance, beginning of period at Dec. 31, 2011	$95,059							$85,940	$0	$17								$40,020								$74,508	($15,972)							($3,514)
Balance, beginning of period (in shares) at Dec. 31, 2011								2,439,739	290,277	17,158,904
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued (in shares)										2,900,000
Stock issued	32,364									3								32,361
Conversion to common stock (in shares)								-2,439,739	-290,277	-21,840,128
Conversion to common stock	85,940							-85,940	0	22								85,918
Offering issuance costs	-3,395																	-3,395
Issuance of restricted stock (in shares)										213,656
Stock issued in connection with acquisition (in shares)											53,336	434,546	326,344
Stock issued in connection with acquisition		640	3,607																640	-346	-2,969							3,953	2,969
Stock-based compensation expense	6,826																	6,826
Proceeds from stock options exercises (in shares)	1,552,742									1,515,580
Proceeds from stock options exercises	4,965									2								4,963
Treasury stock retirement																		-353									353
Excess tax benefits	3,297																	3,297
Currency translation adjustment	2,493																																	2,493
Net income	54,484																									54,484
Balance, end of period at Dec. 31, 2012	286,280							0	0	44								166,962								128,992	-8,697							-1,021
Balance, end of period (in shares) at Dec. 31, 2012								0	0	44,442,494
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued (in shares)										14,041
Stock issued in connection with acquisition (in shares)													1,483
Stock issued in connection with acquisition																					-13								13
Stock-based compensation expense	13,150																	13,150
Proceeds from stock options exercises (in shares)	2,156,898									2,156,898
Proceeds from stock options exercises	9,287									2								9,285
Excess tax benefits	6,201																	6,201
Currency translation adjustment	-811																																	-811
Net income	61,994																									61,994
Balance, end of period at Dec. 31, 2013	376,101							0	0	46								195,585								190,986	-8,684							-1,832
Balance, end of period (in shares) at Dec. 31, 2013								0	0	46,614,916
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued (in shares)										7,738
Awards forfeited/cancelled										-24,474
Forfeiture of stock issued in connection with acquisition																		223									-223
Stock issued in connection with acquisition (in shares)														2,289	179,104	262,277	90,864
Stock issued in connection with acquisition					2,788																	-21	1,158	-2,386	-827					21	1,630	2,386	827
Stock-based compensation expense	21,397																	21,397
Proceeds from stock options exercises (in shares)	1,171,097									1,171,097
Proceeds from stock options exercises	10,598									2								10,596
Excess tax benefits	3,776																	3,776
Prior periods retained earning adjustment																										-29								29
Currency translation adjustment	-20,251																																	-20,251
Net income	69,641			806	-3,090	822	-72																			69,641
Balance, end of period at Dec. 31, 2014	$464,050							$0	$0	$48								$229,501								$260,598	($4,043)							($22,054)
Balance, end of period (in shares) at Dec. 31, 2014								0	0	48,303,811

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$69,641,000	$61,994,000	$54,484,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	17,483,000	15,120,000	10,882,000
Bad debt expense	817,000	335,000	662,000
Deferred taxes	-3,270,000	41,000	-3,933,000
Stock-based compensation expense	24,620,000	13,150,000	6,826,000
Impairment and acquisition related charges	7,907,000	0	0
Excess tax benefit on stock-based compensation plans	-3,776,000	-6,201,000	-3,297,000
Non-cash stock charge	0	0	640,000
Other	735,000	1,199,000	-66,000
(Increase)/ decrease in operating assets:
Accounts receivable	-30,410,000	-17,302,000	-12,664,000
Unbilled revenues	-11,134,000	-9,833,000	-6,905,000
Prepaid expenses and other assets	565,000	587,000	-1,339,000
Increase/ (decrease) in operating liabilities:
Accounts payable	-2,603,000	-2,900,000	1,407,000
Accrued expenses and other liabilities	11,492,000	501,000	-5,825,000
Deferred revenues	-1,514,000	-2,325,000	-767,000
Due to employees	7,453,000	785,000	2,896,000
Taxes payable	16,868,000	3,074,000	5,498,000
Net cash provided by operating activities	104,874,000	58,225,000	48,499,000
Cash flows from investing activities:
Purchases of property and equipment	-11,916,000	-13,360,000	-13,376,000
Payment for construction of corporate facilities	-3,924,000	-2,560,000	-13,701,000
Employee housing loans	-1,740,000	-7,982,000	0
Proceeds from repayments of employee housing loans	1,793,000	2,189,000	0
Decrease in restricted cash and time deposits, net	1,430,000	429,000	470,000
Increase in other long-term assets, net	-1,479,000	-516,000	-69,000
Acquisition of businesses, net of cash acquired (Note 2)	-37,093,000	-20,000	-32,951,000
Net cash used in investing activities	-52,929,000	-21,820,000	-59,627,000
Cash flows from financing activities:
Proceeds related to stock options exercises	10,571,000	9,300,000	4,951,000
Excess tax benefit on stock-based compensation plans	3,776,000	6,201,000	3,297,000
Net proceeds from issuance of common stock in initial public offering	0	0	32,364,000
Costs related to stock issue	0	0	-1,765,000
Acquisition of business, deferred consideration	-4,000,000	0	0
Net cash provided by financing activities	10,347,000	15,501,000	38,847,000
Effect of exchange rate changes on cash and cash equivalents	-10,965,000	-811,000	1,597,000
Net increase in cash and cash equivalents	51,327,000	51,095,000	29,316,000
Cash and cash equivalents, beginning of period	169,207,000	118,112,000	88,796,000
Cash and cash equivalents, end of period	220,534,000	169,207,000	118,112,000
Supplemental disclosures of cash paid:
Income taxes	11,756,000	10,207,000	13,065,000
Bank interest	7,000	26,000	14,000
Deferred consideration payable	1,022,000	0	0
Contingent consideration payable	36,322,000	0	0
Incurred but not paid costs	$0	$0	$96,000

NATURE_OF_BUSINESS_AND_SIGNIFI

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES	NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES
	EPAM is a leading global provider of complex software engineering solutions and information technology ("IT") services to clients throughout North America, Western and Eastern Europe, Russia and Asia. The Company serves primarily Fortune Global 2000 companies in various industries with the main focus on Independent Software Vendors (“ISVs”) and technology, banking and financial services, business information and media, and travel and hospitality. Other industries include retail, energy, life sciences, healthcare, telecommunications, and government.
	Since EPAM’s inception in 1993, the Company has focused on providing software product development services, software engineering and vertically-oriented custom development solutions through its global delivery model. This has served as a foundation for the Company’s other solutions, including custom application development, application testing, platform-based solutions, application maintenance and support, and infrastructure management.
	The Company is incorporated in Delaware with headquarters in Newtown, PA, with multiple delivery centers located in Belarus, Ukraine, Russia, Hungary, Kazakhstan, Bulgaria, China, Armenia and Poland, and client management locations in the United States, Canada, the United Kingdom, Germany, Sweden, Switzerland, Netherlands, Russia, Kazakhstan, Singapore, Hong Kong and Australia.
	Emerging growth company status — In April 2012, several weeks after EPAM’s initial public offering in February 2012, President Obama signed into law the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). The JOBS Act contains provisions that relax certain requirements for “emerging growth companies” that otherwise apply to larger public companies. For as long as a company retains emerging growth company status, it will not be required to (1) provide an auditor’s attestation report on the Company’s internal control over financial reporting, otherwise required by Section 404(b) of the Sarbanes-Oxley Act of 2002, (2) comply with any new or revised financial accounting standard applicable to public companies until such standard is also applicable to private companies, (3) comply with certain new requirements adopted by the Public Company Accounting Oversight Board, (4) provide certain disclosure regarding executive compensation required of larger public companies or (5) hold shareholder advisory votes on matters relating to executive compensation. Based on EPAM's market capitalization on June 30, 2014, it was deemed a large accelerated filer as of December 31, 2014. Therefore, EPAM no longer qualifies as an emerging growth company.
	Principles of Consolidation — The consolidated financial statements include the financial statements of EPAM Systems, Inc. and its subsidiaries. All intercompany balances and transactions have been eliminated.
	Use of Estimates — The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions. These estimates and assumptions affect reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as revenues and expenses during the reporting period. The Company bases its estimates and judgments on historical experience, knowledge of current conditions and its beliefs of what could occur in the future, given available information. Actual results could differ from those estimates, and such differences may be material to the financial statements.
	Revenue Recognition — The Company recognizes revenue when realized or realizable and earned, which is when the following criteria are met: persuasive evidence of an arrangement exists; delivery has occurred; the sales price is fixed or determinable; and collectability is reasonably assured. Determining whether and when some of these criteria have been satisfied often involves assumptions and judgments that can have a significant impact on the timing and amount of revenue we report. If there is an uncertainty about the project completion or receipt of payment for the services, revenues are deferred until the uncertainty is sufficiently resolved. At the time revenues are recognized, the Company provides for any contractual deductions and reduces revenues accordingly. The Company defers amounts billed to its clients for revenues not yet earned. Such amounts are anticipated to be recorded as revenues as services are performed in subsequent periods. Unbilled revenues represent services provided which are billed subsequent to the period end in accordance with the contract terms.
	The Company derives its revenues from a variety of service offerings, which represent specific competencies of its IT professionals. Contracts for these services have different terms and conditions based on the scope, deliverables, and complexity of the engagement, which require management to make judgments and estimates in determining appropriate revenue recognition pattern. Fees for these contracts may be in the form of time-and-materials or fixed-price arrangements.
	The majority of the Company’s revenues (84.7% of revenues in 2014, 82.3% in 2013 and 84.1% in 2012) is generated under time-and-material contracts whereby revenues are recognized as services are performed with the corresponding cost of providing those services reflected as cost of revenues when incurred. The majority of such revenues are billed on an hourly, daily or monthly basis whereby actual time is charged directly to the client.
	Revenues from fixed-price contracts (13.6% of revenues in 2014, 15.7% in 2013 and 13.7% in 2012) are determined using the proportional performance method. In instances where final acceptance of the product, system, or solution is specified by the client, revenues are deferred until all acceptance criteria have been met. In absence of a sufficient basis to measure progress towards completion, revenue is recognized upon receipt of final acceptance from the client. In order to estimate the amount of revenue for the period under the proportional performance method, the Company determines the percentage of actual labor hours incurred as compared to estimated total labor hours and applies that percentage to the consideration allocated to the deliverable. The complexity of the estimation process and factors relating to the assumptions, risks and uncertainties inherent with the application of the proportional performance method of accounting affects the amounts of revenues and related expenses reported in the Company’s consolidated financial statements. A number of internal and external factors can affect such estimates, including labor hours and specification and testing requirement changes. The cumulative impact of any revision in estimates is reflected in the financial reporting period in which the change in estimate becomes known. No significant revisions occurred in each of the three years ended December 31, 2014, 2013 and 2012. The Company’s fixed price contracts are generally recognized over a period of 12 months or less.
	The Company reports gross reimbursable “out-of-pocket” expenses incurred as both revenues and cost of revenues in the consolidated statements of income and comprehensive income.
	Cost of Revenues (Exclusive of Depreciation and Amortization) — Consists principally of salaries, employee benefits, stock compensation expense and non-reimbursable travel costs for IT professionals, and subcontractor fees.
	Selling, General and Administrative Expenses — Consist of expenses associated with promoting and selling the Company’s services and include such items as the cost of advertising and other promotional activities as well as sales and marketing personnel salaries, stock compensation expense and related fringe benefits, commissions and travel. General and administrative expenses include other operating items such as officers’ and administrative personnel salaries, stock compensation expense and related fringe benefits as well as legal and audit expenses, insurance, provision for doubtful accounts, and operating lease expenses.
	Fair Value of Financial Instruments — The Company makes significant assumptions about fair values of its financial instruments. Fair value is determined based on the assumptions that market participants would use in pricing the asset or liability. The Company utilizes the following fair value hierarchy in determining fair values:
	Level 1 — Quoted prices for identical assets or liabilities in active markets.
	Level 2 — Inputs other than quoted prices within Level 1 that are observable either directly or indirectly, including quoted prices in markets that are not active, quoted prices in active markets for similar assets or liabilities, and observable inputs other than quoted prices such as interest rates or yield curves.
	Level 3 — Unobservable inputs reflecting our view about the assumptions that market participants would use in pricing the asset or liability.
	Where the fair values of financial assets and liabilities recorded in the consolidated balance sheets cannot be derived from an active market, they are determined using a variety of valuation techniques. These valuation techniques include a net present value technique, comparison to similar instruments with market observable inputs, options pricing models and other relevant valuation models. Inputs into these models are taken from observable market data whenever possible, but in instances where it is not reasonably feasible, a degree of judgment is required to establish fair values.
	Financial Assets and Liabilities Measured At Fair Value on a Recurring Basis
	The Company had no assets or liabilities measured at fair value on a recurring basis as of December 31, 2014 and 2013, other than contingent liabilities in connection with the acquisitions of businesses.
	At December 31, 2014, contingent liabilities measured at fair value on a recurring basis comprised contingent consideration payable in cash and stock, and performance-based awards issued to certain former owners of the acquired businesses in exchange for future services.
	The Company estimates the fair value of contingent liabilities based on certain performance milestones of the acquired businesses, and estimated probabilities of achievement, then discounts the liabilities to present value using the Company’s cost of debt for the cash component of contingent consideration, and risk free rate for the stock component of a contractual contingency. Contingent liabilities are valued using significant inputs that are not observable in the market which are defined as Level 3 inputs pursuant to fair value measurement accounting. The Company believes its estimates and assumptions are reasonable, however, there is significant judgment involved. Changes in the fair value of contingent consideration liabilities primarily result from changes in the timing and amount of specific milestone estimates and changes in probability assumptions with respect to the likelihood of achieving the various earnout criteria. These changes could cause a material impact to, and volatility in the Company’s operating results. See Note 17 for contingent liabilities activity.
	Financial Assets and Liabilities Measured At Fair Value on a Non-Recurring Basis
	The amounts of the Company’s financial assets and liabilities, with the exceptions of employee housing loans and other employee loans described further herein, approximate fair value because of their short-term maturities.
	Employee Housing Loans — The housing loans were classified as Level 3 measurements within the fair value hierarchy because they were valued using significant unobservable inputs. The estimated fair value of these housing loans upon initial recognition was computed by projecting the future contractual cash flows to be received from the loans and discounting those projected net cash flows to a present value, which is the estimated fair value (the “Income Approach”). In applying the Income Approach, the Company analyzed similar loans offered by third-party financial institutions in Belarusian Rubles (“BYR”) and adjusted the interest rates charged on such loans to exclude the effects of underlying economic factors, such as inflation and currency devaluation. The Company also assessed the probability of future defaults and associated cash flows impact. In addition, the Company separately analyzed the rate of return that market participants in Belarus would require when investing in unsecured USD-denominated government bonds with similar maturities (a “risk-free rate”) and evaluated a risk premium component to compensate the market participants for the credit and liquidity risks inherent in the loans’ cash flows. As a result of the analysis performed, the Company determined the carrying values of the housing loans issued during the year ended December 31, 2014 approximated their fair values upon initial recognition. The Company also estimated the fair values of the housing loans that were outstanding as of December 31, 2014 and 2013 using the inputs noted above and determined their fair values approximated the carrying values as of that date.
	Employee Loans, Other — The Company also issues short-term non-interest bearing relocation loans and other employee loans. These loans are considered Level 3 measurements. The Company’s Level 3, unobservable inputs reflect its assumptions about the factors that market participants use in pricing similar receivables, and are based on the best information available in the circumstances. Due to the short-term nature of employee loans (i.e., the relatively short time between the origination of the instrument and its expected realization), the carrying amount is a reasonable estimate of fair value. As of December 31, 2014, the carrying values of these employee loans approximated their fair values.
	Business Combinations — The Company accounts for its business combinations using the acquisition accounting method, which requires it to determine the fair value of net assets acquired and the related goodwill and other intangible assets. The Company identifies and attributes fair values and estimated lives to the intangible assets acquired and allocates the total cost of an acquisition to the underlying net assets based on their respective estimated fair values. Determining the fair value of assets acquired and liabilities assumed requires management’s judgment and involves the use of significant estimates, including projections of future cash inflows and outflows, discount rates, asset lives and market multiples. There are different valuation models for each component, the selection of which requires considerable judgment. These determinations will affect the amount of amortization expense recognized in future periods. The Company bases its fair value estimates on assumptions it believes are reasonable, but recognizes that the assumptions are inherently uncertain.
	If initial accounting for the business combination has not been completed by the end of the reporting period in which the business combination occurs, provisional amounts are reported for which the accounting is incomplete, with retrospective adjustment made to such provisional amounts during the measurement period to present new information about facts and circumstances that existed as of the acquisition date. Once the measurement period ends, and in no case beyond one year from the acquisition date, revisions of the accounting for the business combination are recorded in earnings.
	All acquisition-related costs, other than the costs to issue debt or equity securities, are accounted for as expenses in the period in which they are incurred. Changes in fair value of contingent consideration arrangements that are not measurement period adjustments are recognized in earnings. Payments to settle contingent consideration, if any, are reflected in cash flows from financing activities and the changes in fair value are reflected in cash flows from operating activities in the Company’s consolidated statements of cash flows.
	The Company’s acquisitions usually do not have significant amounts of tangible assets, as the principal assets typically acquired are customer relationships, trade names, non-competition agreements, and workforce. As a result, a substantial portion of the purchase price is allocated to goodwill and other intangible assets.
	Cash and Cash Equivalents — Cash equivalents are short-term, highly liquid investments that are readily convertible into cash, with maturities of three months or less at the date acquired. As of December 31, 2014 and 2013 the Company had no cash equivalents.
	Restricted Cash — Restricted cash represents cash that is restricted by agreements with third parties for special purposes and includes time deposits. See Note 6 for items that constitute restricted cash.
	Accounts Receivable — Accounts receivable are stated net of an allowance for doubtful accounts. Outstanding accounts receivable are reviewed periodically and allowances are provided at such time the management believes it is probable that such balances will not be collected within a reasonable time. The allowance for doubtful accounts is determined by evaluating the relative creditworthiness of each client, historical collections experience and other information, including the aging of the receivables. Accounts receivable are generally written off when they are deemed uncollectible. Bad debts are recorded based on historical experience and management's evaluation of accounts receivable.
	The table below summarizes movements in qualifying accounts for the years ended December 31, 2014, 2013 and 2012:
		Balance at		Charged to Costs		Deductions/			Balance at End of Year
		Beginning of		and Expenses		Other
		Period
	Allowance for Doubtful Accounts (Billed and Unbilled):
	Fiscal Year 2012	$	2,250	$	1,244	$	(1,291	)	$	2,203
	Fiscal Year 2013	2,203		619		(1,022		)	1,800
	Fiscal Year 2014	1,800		1,325		(944		)	2,181
	Employee Loans — Loans are initially recorded at their fair value, and subsequently measured at their amortized cost, less allowance for loan losses, if any. The Company intends to hold all employee loans until their maturity. Interest income is reported using the effective interest method. Where applicable, loan origination fees, net of direct origination costs, are deferred and recognized in interest income over the life of the loan.
	Property and Equipment — Property and equipment acquired in the ordinary course of the Company’s operations are stated at cost, net of accumulated depreciation. Depreciation is calculated on the straight-line basis over the estimated useful lives of the assets generally ranging from three to 50 years. Leasehold improvements are amortized on a straight-line basis over the shorter of the term of the lease or the estimated useful life of the improvement. Maintenance and repairs are expensed as incurred.
	Goodwill and Other Intangible Assets — Goodwill and intangible assets that have indefinite useful lives are treated consistently with ASC 350. They are tested annually for impairment and are not amortized.
	The Company performs an annual impairment test by comparing the respective fair value of its reporting units to their respective carrying values to identify if any impairment indicators exist. If an indicator of impairment is identified, the implied fair value of the reporting unit’s goodwill is compared to its carrying amount, and the impairment loss is measured by the excess of the carrying value over fair value. The fair values are estimated using a combination of the income approach, which incorporates the use of the discounted cash flow method, and the market approach, which incorporates the use of earnings multiples based on market data. These valuations are considered Level 3 measurements under FASB ASC Topic 820. The Company utilizes estimates to determine the fair value of the reporting units such as future cash flows, growth rates, capital requirements, effective tax rates and projected margins, among other factors. Estimates utilized in the future evaluations of goodwill for impairment could differ from estimates used in the current period calculations. The Company is also required to assess the goodwill of its reporting units for impairment between annual assessment dates when events or circumstances dictate.
	Intangible assets that have finite useful lives are amortized over their estimated useful lives on a straight-line basis.
	Effective in the fourth quarter of 2013, the Company changed the annual goodwill impairment assessment date for all of its reporting units from December 31st to October 31st, which represented a voluntary change in the annual goodwill impairment testing date. The Company evaluates the recoverability of goodwill at a reporting unit level and it had three reporting units, which had goodwill, that were subject to the annual impairment testing in 2014. See Note 3 for disclosure regarding goodwill and intangible assets.
	Impairment of Long-Lived Assets — Long-lived assets, such as property and equipment, and finite lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and exceeds the asset's fair value. When the carrying value of an asset is more than the sum of the undiscounted cash flows that are expected to result from the asset's use and eventual disposition, it is considered to be unrecoverable. Therefore, when an asset’s carrying value will not be recovered and it is more than its fair value the Company would deem the asset to be impaired. Property and equipment held for disposal are carried at the lower of the current carrying value or fair value less estimated costs to sell. The Company did not incur any impairment of long-lived assets for the years ended December 31, 2014, 2013 and 2012.
	Income Taxes — The provision for income taxes includes federal, state, local and foreign taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences of temporary differences between the financial statement carrying amounts and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which the temporary differences are expected to be reversed. Changes to enacted tax rates would result in either increases or decreases in the provision for income taxes in the period of changes. The Company evaluates the realizability of deferred tax assets and recognizes a valuation allowance when it is more likely than not that all, or a portion of, deferred tax assets will not be realized.
	The realization of deferred tax assets is primarily dependent on future earnings. Any reduction in estimated forecasted results may require that we record valuation allowances against deferred tax assets. Once a valuation allowance has been established, it will be maintained until there is sufficient positive evidence to conclude that it is more likely than not that the deferred tax assets will be realized. A pattern of sustained profitability will generally be considered as sufficient positive evidence to reverse a valuation allowance. If the allowance is reversed in a future period, the income tax provision will be correspondingly reduced. Accordingly, the increase and decrease of valuation allowances could have a significant negative or positive impact on future earnings. See Note 10 to the consolidated financial statements for further information.
	Changes in tax laws and rates may affect recorded deferred tax assets and liabilities and our effective tax rate in the future. The American Taxpayer Relief Act of 2012 (the “Act”) was signed into law on January 2, 2013. Because a change in tax law is accounted for in the period of enactment, certain provisions of the Act benefiting the Company’s 2012 U.S. federal taxes, including the Subpart F controlled foreign corporation look-through exception were not recognized in the Company’s 2012 financial results and instead were reflected in the Company’s 2013 financial results.
	Earnings per Share (“EPS”) — Basic EPS is computed by dividing the net income applicable to common stockholders for the period by the weighted average number of shares of common stock outstanding during the same period. The Company’s Series A-1 Preferred, Series A-2 Preferred, and Series A-3 Preferred Stock, that had been outstanding and convertible into common stock until February 13, 2012 (the date of the Company’s initial public offering), and our puttable common stock were considered participating securities since these securities had non-forfeitable rights to dividends or dividend equivalents during the contractual period and thus required the two-class method of computing EPS. When calculating diluted EPS, the numerator is computed by adding back the undistributed earnings allocated to the participating securities in arriving at the basic EPS and then reallocating such undistributed earnings among our common stock, participating securities and the potential common shares that result from the assumed exercise of all dilutive options. The denominator is increased to include the number of additional common shares that would have been outstanding had the options been issued.
	Stock-Based Compensation — Equity-based compensation cost relating to the issuance of share-based awards to employees is based on the fair value of the award at the date of grant, which is expensed ratably over the requisite service period, net of estimated forfeitures. The forfeiture assumption is ultimately adjusted to the actual forfeiture rate. Therefore, changes in the forfeiture assumptions may affect the timing of the total amount of expense recognized over the vesting period. The service period is the period over which the employee performs the related services, which is normally the same as the vesting period. Equity-based awards that do not require future service are expensed immediately. Equity-based awards that do not meet criteria for equity classification are recorded in liabilities and adjusted to fair value at the end of each reporting period. Distributions associated with liability-classified awards not expected to vest are accounted for as compensation expense in the consolidated statements of income and comprehensive income.
	Off-Balance Sheet Financial Instruments — Include credit instruments, such as standby letters of credit and guarantees issued under customer contracts. The face amount for these items represents the exposure to loss, before considering available collateral or the borrower’s ability to repay. Such financial instruments are recorded when they are funded. Loss contingencies arising from off-balance sheet credit exposures are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. The Company does not believe there are such matters that will have a material effect on the consolidated financial statements.
	Foreign Currency Translation — Assets and liabilities of consolidated foreign subsidiaries, whose functional currency is the local currency, are translated to U.S. dollars at period end exchange rates. Revenues and expenses are translated to U.S. dollars at daily exchange rates. The adjustment resulting from translating the financial statements of such foreign subsidiaries to U.S. dollars is reflected as a cumulative translation adjustment and reported as a component of accumulated other comprehensive income.
	The Company reports the effect of exchange rate changes on cash balances held in foreign currencies as a separate item in the reconciliation of the changes in cash and cash equivalents during the period. Transaction gains and losses are included in the period in which they occur.
	Risks and Uncertainties — Principally all of the Company’s IT delivery centers and a majority of its employees are located in Central and Eastern Europe and the APAC region. As a result, the Company may be subject to certain inherent risks associated with international operations, including the application and imposition of protective legislation and regulations relating to import and export; difficulties in enforcing intellectual property and contractual rights; complying with a wide variety of foreign laws; potentially adverse tax consequences; tariffs, quotas and other trade protection methods; and overall foreign policy and variability of foreign economic conditions.
	Concentration of Credit — The Company maintains cash and cash equivalents and short-term investments with financial institutions. The Company determined that the Company's credit policies reflect normal industry terms and business risk and there is no expectation of non-performance by the counterparties. As of December 31, 2014, $59.3 million of total cash was held in CIS countries, with $34.2 million of that in Belarus. Banking and other financial systems in the CIS region are less developed and regulated than in some more developed markets, and legislation relating to banks and bank accounts is subject to varying interpretations and inconsistent application. Banks in the CIS region generally do not meet the banking standards of more developed markets and bank deposits made by corporate entities in the CIS region are not insured. The CIS banking sector remains subject to periodic instability and the transparency of the banking sector lags behind international standards. A banking crisis, bankruptcy or insolvency of banks that process or hold our funds, particularly in Belarus, may result in the loss of our deposits or adversely affect our ability to complete banking transactions in the CIS region, which could materially adversely affect our business and financial condition.
	As of December 31, 2014, unbilled trade receivables from one customer, UBS AG, individually exceeded 10% and accounted for 16.5% of our total unbilled trade receivables as of that date. There were no customers individually exceeding 10% of our billed trade receivables as of December 31, 2014.
	During the years ended December 31, 2014, 2013 and 2012, revenues from our top five customers were $239,396, $169,987 and $134,484, respectively, representing 32.8%, 30.6% and 31.0%, respectively, of total revenues in the corresponding periods. Revenues from our top ten customers were $320,126, $234,955 and $192,426 in 2014, 2013 and 2012, respectively, representing 43.9%, 42.3% and 44.4%, respectively, of total revenues in corresponding periods.
	During the year ended December 31, 2014, the Company had one customer, UBS AG, with revenues of $97.6 million, which accounted for more than 10% of total revenues. No customer accounted for over 10% of total revenues in 2013 and 2012.
	During the years ended December 31, 2014, 2013 and 2012 the Company incurred subcontractor costs of $1,885, $2,078 and $3,535, respectively, to a vendor for staffing, consulting, training, recruiting and other logistical / support services provided for the Company’s delivery and development operations in Eastern Europe. Such costs are included in cost of revenues and sales, general and administrative expenses, as appropriate, in the accompanying consolidated statements of income and comprehensive income.
	Foreign currency risk — The Company generates revenues in various global markets based on client contracts obtained in non-U.S. dollar currencies, principally, Euros, British pounds, Canadian dollars, and Russian rubles. The Company incurs expenditures in non-U.S. dollar currencies, principally in Hungarian forints, Euros, Russian rubles, and Hong Kong dollars and China yuan renminbi (“CNY”) associated with the IT delivery centers located in CEE and APAC regions. The Company is exposed to fluctuations in foreign currency exchange rates primarily on accounts receivable and unbilled revenues from sales in these foreign currencies, and cash flows for expenditures in foreign currencies. The Company does not use derivative financial instruments to hedge the risk of foreign exchange volatility.
Interest rate risk — The Company’s exposure to market risk is influenced primarily by changes in interest rates on interest payments received on cash and cash equivalent deposits and paid on any outstanding balance on the Company's revolving line of credit, which is subject to a variety of rates depending on the type and timing of funds borrowed (see Note 12). The Company does not use derivative financial instruments to hedge the risk of interest rate volatility.
Recent Accounting Pronouncements
In November 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-17, Business Combinations (Topic 805): Pushdown Accounting. The update provides an acquired entity with an option to apply pushdown accounting in its separate financial statements upon occurrence of an event in which an acquirer obtains control of the acquired entity. An acquired entity may also elect the option to apply pushdown accounting in the reporting period in which the change-in-control event occurs. However, if the financial statements for the period in which the most recent change-in-control event occurred already have been issued or made available to be issued, the application of this guidance would be a change in accounting principle. The amendment is effective on November 18, 2014. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements.
In November 2014, the FASB issued ASU 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity. The update aims to eliminate the use of different methods in practice and thereby reduce existing diversity under GAAP in the accounting for hybrid financial instruments issued in the form of a share. The amendments are effective for annual period and interim periods within those annual periods, beginning after December 15, 2015 with early adoption permitted. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements as the Company currently does not engage in derivatives and hedging.
In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. The amendments in this update provide guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. These amendments aim to reduce diversity in the timing and content of footnote disclosures. The amendments in this update are effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter, with early adoption permitted. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements.
In June 2014, the FASB issued ASU 2014-12, which requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in Topic 718, Compensation - Stock Compensation, as it relates to awards with performance conditions that affect vesting to account for such awards. The standard is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015 with early adoption permitted. Entities may apply the amendments in this ASU either: (a) prospectively to all awards granted or modified after the effective date or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements.
In May 2014, the FASB issued ASU 2014-09, which impacts virtually all aspects of an entity’s revenue recognition. The ASU introduces a new five-step revenue recognition model in which an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This ASU also requires disclosures sufficient to enable users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers, including qualitative and quantitative disclosures about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. This standard is effective for fiscal periods beginning after December 15, 2016, including interim periods within that reporting period. The Company is currently evaluating the new guidance to determine the impact it will have on its consolidated financial statements.
In April 2014, the FASB issued ASU 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, which changes the criteria for determining which disposals can be presented as discontinued operations and modifies the related disclosure requirements. To qualify as a discontinued operation the standard requires a disposal to represent a strategic shift that has, or will have, a major effect on an entity's operations and financial results. The standard also expands the disclosures for discontinued operations and requires new disclosures related to individually material dispositions that do not qualify as discontinued operations. The standard is effective prospectively for fiscal periods beginning after December 15, 2014, including interim periods within that reporting period, with early adoption permitted. The implementation of this standard is not expected to have a material impact on the Company’s consolidated financial statements, but will impact the reporting of any future dispositions.
In July 2013, the FASB issued ASU 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. ASU 2013-11 is a new accounting standard on the financial statement presentation of unrecognized tax benefits. The new standard provides that a liability related to an unrecognized tax benefit would be presented as a reduction of a deferred tax asset for a net operating loss carryforward, a similar tax loss or a tax credit carryforward if such settlement is required or expected in the event the uncertain tax position is disallowed. The new standard became effective for the periods commencing January 1, 2014, and it should be applied prospectively to unrecognized tax benefits that exist at the effective date with retrospective application permitted. The Company adopted the ASU effective January 1, 2014. The adoption of this standard did not have any effect on the Company’s consolidated financial statements.

ACQUISITIONS

ACQUISITIONS	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS
	During the year ended December 31, 2014, the Company completed four acquisitions. The acquisitions intend to allow the Company to expand into desirable geographic locations, complement the existing vertical markets, increase the volume of revenue and create new offerings of services currently provided. These acquisitions have been accounted for using the acquisition method for recording business combinations. Acquisitions are settled in cash and/or stock where a portion of the settlement price may be deferred. In some cases, purchase agreements contain contingent consideration in a form of an earnout obligation. The table below discloses respective details of each acquisition.
	Name of Acquisition		Effective Date of Acquisition	Common Shares						Fair Value of Common							Cash, Net of Working Capital and Other Adjustments								Recorded Earnout						Total Recorded Purchase Price		Maximum Potential Earnout Payable
										Shares															Payable
				Issued			Deferred			Issued			Deferred				Paid				Deferred				Cash			Stock
				(in shares)						(in thousands)
	Netsoft		5-Mar-14	—			—			$	—		$	—			$	2,373			$	1,022			$	1,825		$	—		$	5,220	$	1,825
	Jointech		30-Apr-14	—			89,552			—			2,788				10,000				4,000				15,000			5,000			36,788		20,000
	GGA (1)		6-Jun-14	—			—			—			—				14,892				—				11,400			—			26,292
	Great Fridays		31-Oct-14	—			—			—			—				10,854				—				1,173			—			12,027		1,173
				—			89,552			$	—		$	2,788			$	38,119			$	5,022			$	29,398		$	5,000		$	80,327
	-1	The amount of the maximum potential earnout payable to GGA, if any, is not limited based on the terms of the purchase agreement.
	Common shares issued in connection with acquisitions are valued at closing market prices as of the effective date of the respective acquisition. The maximum potential earnouts payable disclosed in the foregoing table represent the maximum amount of additional consideration that could be paid pursuant to the terms of the purchase agreement for the applicable acquisition. The amounts recorded as earnouts payable, which are based upon the estimated future operating results of the acquired businesses within a seven-to twelve-month period subsequent to the acquisition date, are measured at fair value as of the acquisition date and are included on that basis in the recorded purchase price consideration in the foregoing table. The Company will record subsequent changes in the fair value of the earnout obligations, if any, in its consolidated income from operations. Please see Note 17 for discussion around significant inputs and assumptions relating to the earnout obligation.
	Netsoft — On March 5, 2014, the Company completed an acquisition of substantially all of the assets and assumed certain specific liabilities of U.S.-based healthcare technology consulting firm Netsoft Holdings LLC and Armenia-based Ozsoft, LLC (collectively, “Netsoft”). As a result of this transaction, substantially all of the employees of Netsoft, including approximately 40 IT professionals, accepted employment with the Company. In connection with the Netsoft acquisition, the Company agreed to issue a total of 2,289 restricted shares of Company common stock as consideration for future services to key management and employees of Netsoft (the “Netsoft Closing Shares”). The Company agreed to pay a deferred consideration, partially paid in stock of 9,154 restricted shares of Company common stock. Furthermore, subject to attainment of certain performance targets defined in the purchase agreement, the Company will issue 16,349 restricted shares of Company common stock (collectively with the Netsoft Closing Shares and deferred shares, the “Netsoft Employment Shares”). The Netsoft Employment Shares will vest in equal annual installments over a three-year period starting from the date of acquisition. All unvested shares will be forfeited upon termination of services by the Company for cause or by the employee other than for good reason. The Netsoft Employment Shares had an estimated value of $1,017 at the time of grant and will be recorded as stock-based compensation expense over an associated service period of three years (Note 14). Under the terms of this agreement, all of the Netsoft Closing Shares, as well as $256, were placed in escrow for a period of 18 months as security for the indemnification obligations of the sellers under the asset purchase agreement.
	Jointech — On April 30, 2014, the Company acquired all of the outstanding equity of Joint Technology Development Limited, a company organized under the laws of Hong Kong, including its wholly-owned subsidiaries Jointech Software (Shenzhen) Co., Ltd., a company organized under the laws of China, and Jointech Software Pte. Ltd., a company organized under the laws of Singapore (collectively, “Jointech”). Jointech provides strategic technology services to multi-national organizations in investment banking, wealth and asset management. As a result of this transaction, substantially all employees of Jointech, including approximately 216 IT professionals, accepted employment with the Company. In connection with the Jointech acquisition, the Company agreed to issue a total of 89,552 shares of the Company common stock to a former owner of Jointech as consideration for future services on or about the six-month anniversary from the date of acquisition (the “Jointech Closing Shares”). Furthermore, the Company will pay to that former owner up to a maximum of $5,000 in shares of Company common stock determined based on the average closing price per share for the 30-trading day period preceding April 1, 2015 (collectively with the Jointech Closing Shares, the “Jointech Employment Shares”). The Jointech Employment Shares will vest in equal annual installments over a three-year period starting from the date of acquisition. All unvested Jointech Employment Shares will be forfeited upon termination of services for cause by the Company or other than for good reason (as applicable) by either of the two former owners of the acquired business. The aggregate fair value of the Jointech Employment Shares at the date of grant was $7,788 and will be recorded as stock-based compensation expense over an associated service period of three years (Note 14).
	Under the terms of the agreement, 15% of the total purchase price, in cash and stock, including the Jointech Employment Shares, was placed in an escrow account for a period of 18 months as security for the indemnification obligations of the sellers under the stock purchase agreement.
	GGA — On June 6, 2014, the Company acquired substantially all of the assets and assumed certain specific liabilities of GGA Software Services, LLC, Institute of Theoretical Chemistry, Inc., and GGA’s Russian affiliate (collectively, “GGA”). Established in 1994, GGA develops scientific informatics applications and content databases; creates state-of-the-art algorithms and models; and delivers IT support, maintenance, and QA services to the world’s leading healthcare and life sciences companies. As a result of this transaction, substantially all employees of GGA, including approximately 329 IT professionals and 126 scientists, accepted employment with the Company. In connection with the GGA acquisition, the Company agreed to issue a total of 262,277 shares of the Company common stock to the former owners of GGA as consideration for future services (the “GGA Closing Shares”). Furthermore, subject to attainment of specified performance targets, the Company will issue to the former owners of GGA shares of its common stock based on the formula provided in the purchase agreement (collectively with GGA Closing Shares, the “GGA Employment Shares”). The GGA Employment Shares will vest in equal annual installments over a three-year period starting from the date of acquisition. With respect to each former owner, all unvested shares will be forfeited upon either termination of services by the Company for cause or by the employee other than for good reason. The aggregate fair value of the GGA Employment Shares at the date of grant was $20,655 and will be recorded as stock-based expense over an associated service period of three years (Note 14). Under the terms of the agreement, a total of 102,631 of the GGA Employment Shares were placed into an escrow account as security for the indemnification obligations of the sellers under the asset purchase agreement.
	Great Fridays — On October 31, 2014, the Company acquired 100% of the equity interests of Great Fridays Limited and its subsidiaries with intent to expand the Company's product and design service portfolio. Great Fridays Limited, headquartered in Manchester, UK, with offices in London, San Francisco and New York, focuses on bridging the gap between business and design. The acquisition of Great Fridays added approximately 50 creative design professionals to the Company's headcount.
	In connection with the Great Fridays acquisition, the Company agreed to issue a total of 90,864 shares of the Company common stock to the former owners of Great Fridays as consideration for future services (the “Great Fridays Closing Shares”). Furthermore, subject to attainment of specified performance targets, the Company will pay the former owners of Great Fridays up to a maximum of 10,092 shares of the Company common stock (collectively with Great Fridays Closing Shares, the “GF Employment Shares”). The GF Employment Shares will vest in equal annual installments over a three-year period starting from the date of acquisition. With respect to each former owner, all unvested shares will be forfeited upon either termination of services by the Company for cause or by the employee other than for good reason. The aggregate fair value of the GF Employment Shares at the date of grant was $4,823 and will be recorded as stock-based compensation expense over an associated service period of three years (Note 14). Under the terms of the agreement, a total of 28,390 of the GF Employment Shares were placed into an escrow account as security for the indemnification obligations of the sellers under the asset purchase agreement.
	The following is a summary of the preliminary estimated fair values of the net assets acquired at the date of each respective acquisition during the year ended December 31, 2014 as originally reported in the quarterly condensed consolidated financial statements and at December 31, 2014:
		Netsoft							Jointech							GGA								Great Fridays			Total
		At Originally Reported			At December 31, 2014				As Originally Reported			At December 31, 2014				As Originally Reported				At December 31, 2014				At December 31, 2014			As Originally Reported			At December 31, 2014
	Cash and cash equivalents	$	—		$	—			$	871		$	871			$	—			$	—			$	259		$	1,130		$	1,130
	Trade receivables and other current assets	788			788				784			784				5,157				5,471				1,825			8,554			8,868
	Property and equipment and other long-term assets	52			52				338			338				444				444				262			1,096			1,096
	Deferred tax asset	351			—				—			—				4,463				—				—			4,814			—
	Acquired intangible assets	1,700			1,700				25,744			22,485				10,959				10,959				5,747			44,150			40,891
	Goodwill	2,776			2,749				11,033			17,404				6,496				12,115				6,947			27,252			39,215
	Total assets acquired	5,667			5,289				38,770			41,882				27,519				28,989				15,040			86,996			91,200
	Accounts payable and accrued expenses	69			69				728			728				2,593				2,593				872			4,262			4,262
	Deferred revenue	—			—				—			—				—				104				317			317			421
	Due to employees	—			—				1,254			1,254				—				—				624			1,878			1,878
	Deferred tax liability	—			—				—			3,112				—				—				1,200			1,200			4,312
	Total liabilities assumed	69			69				1,982			5,094				2,593				2,697				3,013			7,657			10,873
	Net assets acquired	$	5,598		$	5,220			$	36,788		$	36,788			$	24,926			$	26,292			$	12,027		$	79,339		$	80,327
	The above estimated fair values of the assets acquired and liabilities assumed are provisional and based on the information that was available as of the acquisition date and updated for any changes as of December 31, 2014. During the year ended December 31, 2014, the following updates were made to the initially reported balances with some of the adjustments being reported in the third quarter between goodwill and deferred tax accounts.
	For Netsoft, the deferred tax asset and goodwill were adjusted and decreased the net assets acquired by $378. For Jointech, intangible assets were adjusted to reflect the results of a preliminary valuation report obtained and a deferred tax liability was established, both increasing goodwill with no change to the net assets acquired. For GGA, additional accounts receivable and deferred revenue were recognized, deferred tax assets were netted with recognized deferred tax liabilities, and the final working capital adjustment was completed, which in aggregate increased the net assets acquired by $1,366.
	The Company is gathering additional information necessary to finalize the estimated fair values of intangible assets, deferred income taxes, and other asset and liability amounts. The fair values reflected are subject to change. Such changes could be significant. The Company expects to finalize the valuation and complete the purchase price allocation as soon as practicable but no later than one year from the respective acquisition dates.
	The following table presents the estimated fair values and useful lives of intangible assets acquired during the year ended December 31, 2014:
		Netsoft						Jointech					GGA							Great Fridays
		Weighted Average		Amount				Weighted Average		Amount			Weighted Average			Amount				Weighted Average			Amount
		Useful Life						Useful Life					Useful Life							Useful Life
		(in years)						(in years)					(in years)							(in years)
	Customer relationships	10		$	1,700			10		$	22,173		10			$	10,959			10			$	5,747
	Trade names	—		—				2		312			—			—				—			—
	Total			$	1,700					$	22,485					$	10,959						$	5,747
	The following is a summary of revenues, net income and acquisition-related costs included in the consolidated statements of income and comprehensive income for the year ended December 31, 2014:
		For the Year Ended December 31, 2014
		Netsoft					Jointech					GGA						Great Fridays						Total
	Revenues	$	5,068				$	13,060				$	19,809					$	1,821					$	39,758
	Net Income	806		1			(3,090		)	2		822			3			(72		)	4			(1,534		)
	Acquisition-related costs	$	75				$	361				$	325					$	24					$	785
	-1	Included in net income is $252 of stock-based compensation expense related to the Netsoft Employment Shares for the year ended December 31, 2014.
	-2	Included in net income is $1,738 of stock-based compensation expense related to the Jointech Employment Shares for the year ended December 31, 2014.
	-3	Included in net income is $4,322 of stock-based compensation expense related to the GGA Employment Shares for the year ended December 31, 2014.
	-4	Included in net income is $239 of stock-based compensation expense related to the Great Fridays Employment Shares for the year ended December 31, 2014.
	Aggregate revenues generated by the acquired companies for the year ended December 31, 2013, were approximately $46.5 million. Pro forma results of operations for the acquisition transactions were not presented because the effects of the acquisitions were not material to the Company’s consolidated results of operation, individually or in the aggregate.

GOODWILL_AND_INTANGIBLE_ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	GOODWILL AND INTANGIBLE ASSETS - NET
	Goodwill by reportable segment was as follows:
		North America				Europe				Russia				Total
	Balance as of January 1, 2013	$	16,643			$	2,864			$	3,191			$	22,698
	Net effect of foreign currency exchange rate changes	(205		)		—				(225		)		(430		)
	Balance as of December 31, 2013	16,438				2,864				2,966				22,268
	Acquisition of Netsoft (Note 2)	2,749				—				—				2,749
	Acquisition of Jointech (Note 2)	—				17,404				—				17,404
	Acquisition of GGA (Note 2)	12,115				—				—				12,115
	Acquisition of Great Fridays (Note 2)	—				6,947				—				6,947
	Goodwill written-off	—				—				(2,241		)		(2,241		)
	Net effect of foreign currency exchange rate changes	(224		)		(876		)		(725		)		(1,825		)
	Balance as of December 31, 2014	$	31,078			$	26,339			$	—			$	57,417
	Excluded from the table above is the Other segment. As a result of an operating loss in the Other reporting unit for the three months ended June 30, 2011, the Company performed a goodwill impairment test. In assessing impairment in accordance with Accounting Standards Codification, (“ASC”) No. 350, “Intangibles-Goodwill and Other,” the Company determined that the fair value of the Other reporting unit, based on the total of the expected future discounted cash flows directly related to the reporting unit, was below the carrying value of the reporting unit. The Company completed the second step of the goodwill impairment test, resulting in an impairment charge of $1,697 in the Other operating segment. As of December 31, 2014, 2013 and 2012 the book value of the Other segment was $0.
	The Company performed an annual goodwill impairment test as of October 31, 2014 in accordance with Accounting Standards Codification, (“ASC”) No. 350, “Intangibles-Goodwill and Other.” In assessing impairment both qualitatively and quantitatively based on the total of the expected future discounted cash flows directly related to the reporting unit, the Company determined that the fair value of the Russia reporting unit was below the carrying value of the reporting unit. The Company completed the second step of the goodwill impairment test, resulting in an impairment charge of $2,241 as of December 31, 2014. All existing assets that related to the Russia segment, excluding goodwill and including any unrecognized intangible assets, were assessed by management and deemed to not be impaired.
	There were no accumulated impairments losses in North America or Europe operating segments as of December 31, 2014, 2013 or 2012.
	As part of the Netsoft acquisition, substantially all of the employees of Netsoft accepted employment with the Company. The Company believes the amount of goodwill resulting from the allocation of purchase price to acquire Netsoft is attributable to the workforce of the acquired business. All of the goodwill was allocated to the Company’s U.S. operations and is presented within North America.
	As part of the Jointech acquisition, substantially all of the employees of Jointech continued employment. The Company believes the amount of goodwill resulting from the allocation of purchase price to acquire Jointech is attributable to the workforce of the acquired business. Based on the determination of the reportable units, Jointech has been placed in the Europe reportable unit based on managerial responsibility and consistent with segment reporting. All of the goodwill was allocated to the Company’s UK operations and is presented within Europe segment.
	As part of the GGA acquisition, substantially all of the employees of GGA accepted employment with the Company. The Company believes the amount of goodwill resulting from the allocation of purchase price to acquire GGA is attributable to the workforce of the acquired business. All of the goodwill was allocated to the Company’s U.S. operations and is presented within North America.
	As part of the Great Fridays acquisition, substantially all of the employees of Great Fridays continued employment. The Company believes the amount of goodwill resulting from the allocation of purchase price to acquire Great Fridays is attributable to the workforce of the acquired business. All of the goodwill was allocated to the Company’s U.S. operations and is presented within North America.
		2014
		Weighted average life at acquisition (in years)		Gross carrying amount				Accumulated amortization				Net
												carrying amount
	Client relationships	10		$	48,482			$	(4,664	)		$	43,818
	Trade name	5		6,372				(2,894		)		3,478
	Non-competition agreements	5		813				(420		)		393
	Total			$	55,667			$	(7,978	)		$	47,689
		2013
		Weighted average life at acquisition (in years)		Gross carrying amount				Accumulated amortization				Net
												carrying amount
	Client relationships	9		$	13,432			$	(4,885	)		$	8,547
	Trade name	5		6,232				(1,643		)		4,589
	Non-competition agreements	5		848				(250		)		598
	Total			$	20,512			$	(6,778	)		$	13,734
		2012
		Weighted average life at acquisition (in years)		Gross carrying amount				Accumulated amortization				Net
												carrying amount
	Client relationships	9		$	13,724			$	(3,640	)		$	10,084
	Trade name	5		6,372				(439		)		5,933
	Non-competition agreements	5		881				(64		)		817
	Total			$	20,977			$	(4,143	)		$	16,834
	All of the intangible assets have finite lives and as such are subject to amortization. Recognized amortization expense for the years ended December 31 is presented in the table below:
			For the Years Ended December 31,
			2014				2013				2012
	Client relationships		$	3,843			$	1,373			$	627
	Trade name		1,319				1,222				333
	Non-competition agreements		187				190				64
	Total		$	5,349			$	2,785			$	1,024
	Estimated amortization expenses of the Company’s existing intangible assets for the next five years ending December 31, were as follows:
			Amount
	2015		$	6,520
	2016		6,383
	2017		5,957
	2018		5,032
	2019		4,748
	Thereafter		19,049
	Total		$	47,689

PREPAID_AND_OTHER_CURRENT_ASSE

PREPAID AND OTHER CURRENT ASSETS	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
PREPAID AND OTHER CURRENT ASSETS	PREPAID AND OTHER CURRENT ASSETS
	Prepaid and other current assets consisted of the following:
		December 31,		December 31,
		2014		2013
	Taxes receivable	$	3,966	$	7,295
	Prepaid expenses	3,703		3,399
	Security deposits under operating leases	476		1,005
	Prepaid equipment	185		986
	Unamortized software licenses and subscriptions	454		981
	Due from employees	96		218
	Other	409		471
	Total	$	9,289	$	14,355

EMPLOYEE_LOANS_AND_ALLOWANCE_F

EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES	12 Months Ended
	Dec. 31, 2014
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES	EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES
	In the third quarter of 2012, the Board of Directors of the Company approved the Employee Housing Program (the “Housing Program”), which assists employees in purchasing housing in Belarus in a form of a loan. The Housing Program was designed to be a retention mechanism for the Company’s employees in Belarus and is available to full-time qualified employees who have been with the Company for at least three years. The aggregate maximum lending limit of the program is $10,000, with individual loans not exceeding $50. The housing is sold directly to employees by independent third parties. In addition to the housing loans, the Company issues relocation loans in connection with intra-company transfers, as well as certain other individual loans.
	During the year ended December 31, 2014, loans issued by the Company under the Housing Program were denominated in U.S. Dollars with a 5-year term and carried an interest rate of 7.5%.
	At December 31, 2014 and December 31, 2013, categories of employee loans included in the loan portfolio were as follows:
		December 31,		December 31,
		2014		2013
	Housing loans	$	5,848	$	5,896
	Relocation and other loans	667		494
	Total employee loans	6,515		6,390
	Less:
	Allowance for loan losses	—		—
	Total loans, net of allowance for loan losses	$	6,515	$	6,390
	There were no loans issued to principal officers, directors, or their affiliates during the years ended December 31, 2014, 2013 and 2012.
	On a quarterly basis, the Company reviews the aging of its loan portfolio to evaluate information about the ability of employees to service their debt, including historical payment experience, reasons for payment delays and shortfalls, if any, as well as probability of collecting scheduled principal and interest payments based on the knowledge of individual borrowers, among other factors.
	As of December 31, 2014 and December 31, 2013, there were no material past due or non-accrual employee loans. The Company determined no allowance for loan losses was required regarding its employee loans as of December 31, 2014 and December 31, 2013 and there were no movements in provision for loan losses during the years ended December 31, 2014, 2013 and 2012.

RESTRICTED_CASH_AND_TIME_DEPOS

RESTRICTED CASH AND TIME DEPOSITS	12 Months Ended
	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
RESTRICTED CASH AND TIME DEPOSITS	RESTRICTED CASH AND TIME DEPOSITS
	Restricted cash and time deposits consisted of the following:
		December 31,		December 31,
		2014		2013
	Time deposits	$	—	$	1,188
	Short-term security deposits under customer contracts	—		298
	Long-term deposits under employee loan programs	156		225
	Long-term deposits under operating leases	—		—
	Total	$	156	$	1,711
	There were no time deposits as of December 31, 2014.
	Included in time deposits as of December 31, 2013, was a bank deposit of $1,188, which earned interest at the rate of 2.05%. The deposit matured on October 15, 2014.
	At December 31, 2014 and 2013 short-term security deposits under customer contracts included fixed amounts placed in connection with bank guarantees to secure appropriate performance by the Company. The Company estimates the probability of non-performance under these contracts as remote therefore, no provision for losses has been recognized in respect of these amounts as of December 31, 2014 and 2013.
	Also included in restricted cash as of December 31, 2014 and 2013 were deposits of $156 and $225, respectively, placed in connection with certain employee loan programs (See Note 16).

PROPERTY_AND_EQUIPMENT_NET

PROPERTY AND EQUIPMENT - NET	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT - NET	PROPERTY AND EQUIPMENT — NET
	Property and equipment consisted of the following:
		Useful Life	December 31,			December 31,
		(in years)	2014			2013
	Computer hardware	3	$	32,374		$	29,884
	Leasehold improvements	lease term	6,287			5,903
	Furniture and fixtures	7	7,348			5,688
	Purchased computer software	3	3,606			5,042
	Office equipment	7	5,043			4,679
	Building	50	17,123			16,534
	Construction in progress (Note 16)	n/a	17,885			15,749
			89,666			83,479
	Less accumulated depreciation and amortization		(34,532		)	(30,164		)
	Total		$	55,134		$	53,315
	Depreciation and amortization expense related to property and equipment was $12,134, $12,335 and $9,858 for the years ended December 31, 2014, 2013 and 2012, respectively.

ACCRUED_EXPENSES_AND_OTHER_LIA

ACCRUED EXPENSES AND OTHER LIABILITIES	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
ACCRUED EXPENSES AND OTHER LIABILITIES	ACCRUED EXPENSES AND OTHER LIABILITIES
	Accrued expenses consisted of the following:
		December 31,		December 31,
		2014		2013
	Compensation	$	22,766	$	13,674
	Acquisition related deferred consideration	1,022		—
	Subcontractor costs	2,815		2,933
	Professional fees	1,162		947
	Facilities costs	757		334
	Other	3,681		2,287
	Total	$	32,203	$	20,175

TAXES_PAYABLE

TAXES PAYABLE	12 Months Ended
	Dec. 31, 2014
Taxes Payable, Current [Abstract]
TAXES PAYABLE	TAXES PAYABLE
	Current taxes payable consisted of the following:
		December 31,		December 31,
		2014		2013
	Corporate profit tax	$	7,982	$	3,717
	Value added taxes	6,279		5,975
	Payroll, social security, and other taxes	10,443		4,479
	Total	$	24,704	$	14,171
	As of December 31, 2013, long-term taxes payable included amounts for unrecognized tax benefits and related interest. As of December 31, 2014, there were no long-term taxes payable.

INCOME_TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES
	Income before provision for income taxes shown below was based on the geographic location to which such income was attributed as follows:
		For the Years Ended December 31,
		2014			2013			2012
	Income before income tax expense:
	Domestic	$	(7,229	)	$	7,001		$	9,291
	Foreign	94,182			69,769			56,572
	Total	$	86,953		$	76,770		$	65,863
		For the Years Ended December 31,
		2014			2013			2012
	Income tax expense (benefit) consists of:
	Current
	Federal	$	7,741		$	6,150		$	6,881
	State	338			310			319
	Foreign	12,504			8,275			7,969
	Deferred
	Federal	(3,979		)	(668		)	(625		)
	State	(43		)	14			24
	Foreign	751			695			(3,189		)
	Total	$	17,312		$	14,776		$	11,379
	Deferred tax assets and liabilities are provided for the effects of temporary differences between the tax basis of an asset and liability and its reported amount in the consolidated balance sheets. These temporary differences result in taxable or deductible amounts in future years.
	The components of the Company’s deferred tax assets and liabilities were as follows:
		December 31,			December 31,
		2014			2013
	Deferred tax assets:
	Fixed assets	$	181		$	732
	Intangible assets	3,789			4,532
	Accrued expenses	1,282			3,488
	Net operating loss carryforward	844			—
	Deferred revenue	4,328			2,050
	Stock-based compensation	6,994			407
	Valuation allowance	(149		)	—
	Restricted stock options	2			1,336
	Other assets	30			680
	Deferred tax assets	17,301			13,225
	Deferred tax liabilities:
	Fixed assets	800			804
	Accrued revenue and expenses	635			846
	Deferred inter-company gain	405			405
	Equity compensation	7,013			1,593
	Other liabilities	24			254
	Deferred tax liability	8,877			3,902
	Net deferred tax asset	$	8,424		$	9,323
	At December 31, 2014, the Company had current and non-current deferred tax assets of $2,496 and $11,094, respectively, and current and non-current tax liabilities of $603 and $4,563, respectively. At December 31, 2013, the Company had current and non-current deferred tax assets of $5,392 and $4,557, respectively, and current and non-current tax liabilities of $275 and $351, respectively.
	At December 31, 2014, the Company has a net operating loss in China and Singapore related to the acquisition of Jointech. This net operating loss will be utilized prior to its expiration. No provision has been made for U.S. or non-U.S. income taxes on the undistributed earnings of subsidiaries or for unrecognized deferred tax liabilities for temporary differences related to basis differences in investments in subsidiaries, as such earnings are expected to be permanently reinvested, the investments are essentially permanent in duration, or the Company has concluded that no additional tax liability will arise as a result of the distribution of such earnings. As of December 31, 2014, certain subsidiaries had approximately $340.5 million of undistributed earnings that we intend to permanently reinvest. A liability could arise if our intention to permanently reinvest such earnings were to change and amounts are distributed by such subsidiaries or if such subsidiaries are ultimately disposed. It is not practicable to estimate the additional income taxes related to permanently reinvested earnings or the basis differences related to investments in subsidiaries.
	The provision for income taxes differs from the amount of income tax determined by applying the applicable US statutory federal income tax rate to pretax income as follows:
		For the Years Ended December 31,
		2014			2013			2012
	Statutory federal tax	$	29,564		$	26,102		$	22,393
	Increase/ (decrease) in taxes resulting from:
	State taxes, net of federal benefit	311			368			280
	Provision adjustment for current year uncertain tax position	(1,220		)	—			—
	Effect of permanent differences	8,589			2,524			2,177
	Stock-based compensation	3,782			1,948			1,165
	Rate differential between U.S. and foreign	(24,772		)	(17,279		)	(14,472		)
	Change in foreign tax rate	754			(59		)	148
	Change in valuation allowance	149			489			(489		)
	Other	155			683			177
	Provision for income taxes	$	17,312		$	14,776		$	11,379
	On September 22, 2005, the president of Belarus signed the decree “On the High-Technologies Park” (the “Decree”). The Decree is aimed at boosting the country’s high-technology sector. The Decree stipulates that member technology companies have a 100% exemption from Belarusian income tax of 18% effective July 1, 2006. The Decree is in effect for a period of 15 years from July 1, 2006.
	The Company’s subsidiary in Hungary benefits from a tax credit of 10% of annual qualified salaries, taken over a 4-year period, for up to 70% of the total tax due for that period. The Company has been able to take the full 70% credit for 2008 - 2014. The Hungarian tax authorities repealed the tax credit beginning with 2012. However, credits earned in the years prior to 2012, will be allowed to be used through 2014. The Company has utilized the 70% limit through 2014.
	The aggregate dollar benefits derived from these tax holidays approximated $16.8 million, $9.7 million and $8.5 million for the years ended December 31, 2014, 2013 and 2012, respectively. The benefit the tax holiday had on diluted net income per share approximated $0.34, $0.20 and $0.19 for the years ended December 31, 2014, 2013 and 2012, respectively.
	The liability for unrecognized tax benefits is included in income tax liability within the consolidated balance sheets at December 31, 2014 and 2013. At December 31, 2014 and 2013, the total amount of gross unrecognized tax benefits (excluding the federal benefit received from state tax positions) was $200 and $1,271, respectively, (excluding penalties and interest of $12 and $189, respectively). Of this total, $212 and $1,328, respectively, (net of the federal benefit on state tax issues) represents the amount of unrecognized tax benefits that, if recognized, would favorably affect the effective tax rate in future periods.
	The Company’s policy is to recognize interest and penalties related to uncertain tax positions as a component of its provision for income taxes. The total amount of accrued interest and penalties resulting from such unrecognized tax benefits was $12, $189 and $125 at December 31, 2014, 2013 and 2012, respectively.
The beginning to ending reconciliation of the gross unrecognized tax benefits were as follows:
	For the Years Ended December 31,
	2014			2013			2012
Gross Balance at January 1	$	1,271		$	1,271		$	1,271
Increases in tax positions in current year	—			—			—
Increases in tax positions in prior year	—			—			—
Decreases due to settlement	(1,071		)	—			—
Balance at December 31	$	200		$	1,271		$	1,271
There were no tax positions for which it was reasonably possible that unrecognized tax benefits will significantly increase or decrease within 12 months of the reporting date.
The Company files income tax returns in the United States and in various states, local and foreign jurisdictions. The Company’s significant tax jurisdictions are the U.S. Federal, Pennsylvania, Canada, Russia, Denmark, Germany, Ukraine, the United Kingdom, Hungary, Switzerland and Kazakhstan. As a result of 2014 acquisitions, the Company has an additional filing responsibility in Singapore, Hong Kong and China. The tax years subsequent to 2010 remain open to examination by the Internal Revenue Service. Generally, the tax years subsequent to 2010 remain open to examination by various state and local taxing authorities and various foreign taxing authorities.

EMPLOYEE_BENEFITS

EMPLOYEE BENEFITS	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE BENEFITS	EMPLOYEE BENEFITS
	The Company has established a 401(k) retirement plan, which is a tax-qualified self-funded retirement plan covering substantially all of the Company’s U.S. employees. Under this plan, employees may elect to defer their current compensation by up to the statutory limit. Effective January 1, 2013, the Company provides discretionary matching contributions to the plan up to a maximum of 2.0% of the employee’s eligible compensation. Employer contributions charged to expense for the years ended December 31, 2014 and 2013, were $549 and $404, respectively. The Company does not maintain any defined benefit pension plans or any nonqualified deferred compensation plans.

LONGTERM_DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT
	Revolving Line of Credit — On January 15, 2013, the Company entered into a revolving loan agreement (the “2013 Credit Facility”) with PNC Bank, National Association (the “Bank”). Under the agreement, the Company’s maximum borrowing capacity was set at $40,000. Advances under the 2013 Credit Facility accrued interest at an annual rate equal to the London Interbank Offer Rate, or LIBOR, plus 1.25%.
	On September 12, 2014, the Company terminated the 2013 Credit Facility and entered into a new credit facility (the “2014 Credit Facility”) with PNC Bank, National Association; Santander Bank, N.A; and Silicon Valley Bank (collectively the “Lenders”). The 2014 Credit Facility provides for a borrowing capacity of $100,000, with potential to increase the credit facility up to $200,000 if certain conditions are met. The 2014 Credit Facility matures on September 12, 2019.
	Borrowings under the 2014 Credit Facility may be denominated in U.S. dollars or, up to a maximum of $50,000 in British pounds sterling, Canadian dollars, euros or Swiss francs (or other currencies as may be approved by the lenders). Borrowings under the 2014 Credit Facility bear interest at either a base rate or Euro-rate plus a margin based on the Company’s leverage ratio. Base rate is equal to the highest of (a) the Federal Funds Open Rate, plus 0.5%, (b) the Prime Rate, and (c) the Daily LIBOR Rate, plus 1.0%.
	The 2014 Credit Facility is secured by: (a) all tangible and intangible assets of the Company, and its U.S.-based subsidiaries including all accounts, general intangibles, intellectual property rights and equipment; and (b) all of the outstanding shares of capital stock and other equity interests in U.S.-based subsidiaries of the Company, and 65% of the outstanding shares of capital stock and other equity interests in certain of the Company’s foreign subsidiaries.
	As of December 31, 2014, the borrowing capacity of the Company under the 2014 Credit Facility was $100,000.
	The 2014 Credit Facility contains customary affirmative and negative covenants, including financial and coverage ratios. As of December 31, 2014, the Company was in compliance with all debt covenants as of that date.
	As of December 31, 2014, the Company had no outstanding debt under the 2014 Credit Facility.

COMMON_AND_PREFERRED_STOCK

COMMON AND PREFERRED STOCK	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
COMMON AND PREFERRED STOCK	COMMON AND PREFERRED STOCK
	On January 19, 2012, the Company effected an 8-for-1 stock split of the Company’s common stock, on which date the number of authorized common and preferred stock was increased to 160,000,000 and 40,000,000 shares, respectively. All shares of common stock, options to purchase common stock and per share information presented in the consolidated financial statements have been adjusted to reflect the stock split on a retroactive basis for all periods presented. There was no change in the par value of the Company’s common stock. The ratio by which the then outstanding shares of Series A-1 Preferred, Series A-2 Preferred and Series A-3 Preferred Stock were convertible into shares of common stock was adjusted to reflect the effects of the common stock split, such that each share of preferred stock was convertible into eight shares of common stock.
	In February 2012, the Company completed an initial public offering of 6,900,000 shares of its common stock, which included 900,000 shares of common stock sold by the Company pursuant to an over-allotment option granted to the underwriters, which were sold at a price to the public of $12.00 per share. The offering commenced on February 7, 2012 and closed on February 13, 2012. Of the 6,900,000 shares of common stock sold, the Company issued and sold 2,900,000 shares of common stock and its selling stockholders sold 4,000,000 shares of common stock, resulting in gross proceeds to the Company of $34,800 and $28,969 in net proceeds after deducting underwriting discounts and commissions of $2,436 and offering expenses of $3,395. The Company did not receive any proceeds from the sale of common stock by the selling stockholders.
	On August 20, 2010, the Company entered into an agreement with Instant Information Inc. to issue shares of common stock to Instant Information Inc. as consideration for the acquisition of the assets of Instant Information Inc. subject to achievement of certain financial milestones or upon completion of an initial public offering by the Company. A total of 53,336 shares of common stock were issued to Instant Information Inc. upon completion of the Company’s initial public offering for an aggregate value of $640, which was expensed during the first quarter of 2012.
	Upon the closing of the initial public offering, all outstanding Series-A1 and Series-A2 convertible redeemable preferred stock, and Series A3 convertible preferred stock were converted into a total of 21,840,128 shares of common stock, as shown in the table below.
		Conversion Shares
	Series A-1 Convertible Redeemable Preferred Stock	16,439,480
	Series A-2 Convertible Redeemable Preferred Stock	3,078,432
	Series A-3 Convertible Preferred Stock	2,322,216
	Total	21,840,128
	Series A-1 Convertible Redeemable Preferred Stock (“Series A-1 Preferred”) — On January 20, 2006, Siguler Guff LLC, a New York based private equity investment firm, acting through its affiliated investment funds Russia Partners II LP (“RPII”) and Russia Partners EPAM Fund LP (“RPE”), purchased 657,354 shares of Series A-1 Preferred at $12.17 per share or $8,000. At the same time, RPII and RPE also acquired 11,180,648 shares of the Company’s common stock from existing holders, and the Company enabled RPII and RPE to convert such shares into 1,397,581 shares of Series A-1 Preferred. The difference between the share price of the Series A-1 Preferred ($12.17 per share) and the common stock ($1.13 per share) exchanged of $6,803 has been recorded as a deemed dividend. The Company accreted the 12.5% compounded annual rate of return through April 15, 2010, in accordance with the redemption provision as detailed below. There was no accretion for the years ended December 31, 2014, 2013 and 2012. The ending redemption value was $41,245 at December 31, 2011.
	The terms of the Series A-1 Preferred were as follows:
	Dividends — No dividends will be paid on the Series A-1 Preferred unless dividends are paid on common stock.
	Liquidation — Before any payment to the common stockholders, the Series A-1 Preferred will receive their purchase price of the Series A-1 Preferred ($12.17 per share) plus a 12.5% compounded annual rate of return on the purchase price.
	If the assets distributable to the holders of the Series A Preferred upon a liquidation are insufficient to pay the full Series A-1, A-2 and A-3 Preferred liquidation amounts, then such assets or the proceeds shall be distributed among the holders of the Series A-1, A-2 and A-3 Preferred ratably in proportion to the respective amount to which they otherwise would be entitled.
	The liquidation amount is equal to the carrying value for all periods presented.
	Redemption — At any time after January 1, 2011, if the Company has not affected a qualified public offering, as defined, the holders of at least a majority of the then outstanding shares of Series A-1 Preferred, voting together as a separate class, may by written request, require the Company to redeem all or any number of shares of the Series A-1 Preferred in four equal semi-annual installments beginning thirty calendar days from the date of the redemption election and ending on the date one and one-half years after such date. The Company shall affect such redemptions on the applicable redemption date by paying in cash in exchange for each share of Series A-1 Preferred to be redeemed then outstanding an amount equal to the Series A-1 Preferred liquidation amount ($12.17 per share plus a 12.5% compounded annual rate of return) on such redemption date.
	Pursuant to section 6.8 of the Series A-3 convertible preferred stock purchase agreement, the 12.5% compounded annual return related to the Series A-1 Preferred, which has been part of the Series A-1 liquidation amount, ceases after the date of issuance of the Series A-3 Preferred. EPAM terminated the accretion related to this liquidation amount on or about April 15, 2010.
	Voting — Each holder of a share of Series A-1 Preferred shall be entitled to voting rights and powers equal to the voting rights and powers of the common stock (except as otherwise expressly provided or as required by law) voting together with the common stock as a single class on an as-converted to common stock basis. Each share of Series A-1 Preferred (including fractional shares) shall be entitled to one vote for each whole share of common stock that would be issuable upon conversion of such shares on the record date for determining eligibility to participate in the action being taken.
	Conversion Rights — Any holder of Series A-1 Preferred may convert any share of Series A-1 Preferred held by such holder into a number of shares of common stock determined by dividing (i) the Series A-1 Preferred purchase price ($12.17 per share) by (ii) the Series A-1 conversion price then in effect. The initial conversion price for the Series A-1 Preferred (the “Series A-1 Conversion Price”) shall be equal to the purchase price ($12.17 per share). The Series A-1 Conversion Price from time to time in effect is subject to adjustment, as defined. Each share of Series A-1 Preferred shall automatically be converted into shares of common stock at the then effective applicable Series A-1 Conversion Price upon the earliest of (i) the date specified by vote or written consent or agreement of holders of at least a majority of the shares of Series A-1 Preferred then outstanding, (ii) effective immediately before a qualified public offering, as defined, or (iii) effective upon the closing of a liquidation or a reorganization event, as defined, that results in the receipt of a per share amount of cash proceeds or non-cash property valued equal to or greater than the Series A-1 Preferred liquidation amount, as defined.
	Series A-2 Convertible Redeemable Preferred Stock (“Series A-2 Preferred”) — On February 19, 2008, the Company completed a private placement and raised net proceeds of $47,601 ($50,000 gross less $2,399 costs) from the sale of 675,081 shares of Series A-2 Preferred at a sale price of $74.07 per share. There was no annual accretion for the years ended December 31, 2014, 2013 and 2012. There was no ending carrying value at December 31, 2014, 2013 and 2012, respectively.
	In connection with this private placement, the Company designated the Series A-2 Preferred as a new series of preferred stock and renamed the existing series of shares of Series A preferred stock as Series A-1 Preferred.
	On January 19, 2010, the Company entered into a stock repurchase agreement with certain stockholders to repurchase 290,277 of Series A-2 Convertible Redeemable Preferred Stock at a per share price of $51.85 for a total consideration of $15,050. On November 10, 2010, Board of Directors of the Company voted to retire these shares.
	The Series A-2 Preferred shares had the following rights and preferences:
	Dividends — No dividends will be paid on the Series A-2 Preferred unless dividends are paid on common stock.
	Liquidation — Before any payment to the common stockholders, the Series A-2 Preferred holders will receive their liquidation preference.
	In the event of any liquidation that values 100% of the equity securities of the Company on a fully-diluted basis at an amount that is less than the Series A-2 post-money valuation, as defined, the holders of shares of Series A-2 Preferred shall be entitled to receive either their per share purchase price of the Series A-2 Preferred ($74.07) plus a 12.5% compounded annual rate of return if the purchase price is less than the percentage ceiling amount, defined for purposes of liquidation as 17.1% of cash proceeds or non-cash property received by the Company in the event of any liquidation, or the greater of (1) $74.07 per share and (2) the percentage ceiling amount.
	In the event of liquidation that values 100% of the equity securities of the Company on a fully-diluted basis at an amount that is equal to or greater than the Series A-2 post-money valuation, as defined, the holders of shares of Series A-2 Preferred shall be entitled to receive either their per share purchase price of the Series A-2 Preferred ($74.07) plus a 12.5% to 18% compounded annual rate of return on the purchase price, if greater than the percentage ceiling amount, or the percentage ceiling amount.
	If the assets distributable to the holders of the Series A Preferred upon a liquidation are insufficient to pay the full Series A-1, A-2 and A-3 Preferred liquidation amounts, then such assets or the proceeds shall be distributed among the holders of the Series A-1, A-2 and A-3 Preferred ratably in proportion to the respective amount to which they otherwise would be entitled.
	Redemption — At any time before January 1, 2011, if the Company has not effected a qualified public offering, as defined, the holders of at least a majority of the then outstanding shares of Series A-2 Preferred, may, by written request, require the Company to redeem all or any number of shares of the Series A-2 Preferred in three equal installments payable no later than the 12th, 18th and 24th month following the date of the redemption election. The Company shall effect such redemptions on the applicable redemption date by paying in cash in exchange for each shares of Series A-2 Preferred to be redeemed then outstanding, a per share amount equal to the lesser of (x) an amount that would provide a compounded annual return of 12.5% from the date of initial issuance date and (y) the percentage ceiling amount. At any time on or after January 1, 2011, the redemption per share amount is equal to the lesser of (x) the hurdle amount, an amount that would provide an annual IRR, as defined, from the initial issuance date of such share of at least 17%, provided, however, that the hurdle amount, as defined, shall cease to compound after December 31, 2010 and (y) the percentage ceiling amount, as defined. The percentage ceiling amount means, initially, 17.1% and thereafter adjusted pro rata for any changes in the percentage of capital stock of the Company owned by the holders of shares of Series A-2 Preferred (on a fully diluted basis) multiplied by the aggregate value of all Common Stock (assuming conversion of the Series A Preferred) as reasonably determined by the Board in good faith.
	Voting — Each holder of a Series A-2 Preferred shall be entitled to voting rights and powers equal to the voting rights and powers of common stock (except as otherwise expressly provided or as required by law) voting together with the common stock as a single class on an as-converted to common stock basis. Each share of Series A-2 Preferred (including fractional shares) shall be entitled to one vote for each whole share of common stock that would be issuable upon conversion of such shares on the record date for determining eligibility to participate in the action being taken.
	Conversion rights — Any holder of Series A-2 Preferred may convert any share of Series A-2 Preferred held by such holder into a number of shares of common stock determined by dividing (i) the Series A-2 Preferred purchase price ($74.07 per share) by (ii) the Series A-2 conversion price then in effect. The initial conversion price for the Series A-2 Preferred (the “Series A-2 Conversion Price”) shall be equal to the purchase price ($74.07 per share). The Series A-2 Conversion Price from time in effect is subject to adjustment, as defined. Each share of Series A-2 Preferred shall automatically be converted into shares of common stock at the then effective applicable Series A-2 Conversion Price upon the earliest of (i) the date specified by vote or written consent or agreement of holders of at least a majority of the shares of Series A-2 Preferred then outstanding, (ii) effective immediately before a qualified public offering, as defined. or (iii) effective upon the closing of a liquidation or a reorganization event, as defined, that results in the receipt per share of amount of cash proceeds or non-cash property valued equal to or greater than, the lesser of (x) their purchase price of the Series A-2 Preferred ($74.07 per share) plus a 12.5% compounded annual rate of return on the purchase price and (y) the percentage ceiling amount, as defined.
	Registration Rights — The holders of at least majority of the Series A-2 Preferred holders, may, by written request, require the Company to file a registration statement with certain limitations.
	Series A-3 Convertible Preferred Stock (“Series A-3 Preferred”) — On April 15, 2010, the Company created and issued 290,277 shares of Series A-3 Preferred at $51.85 per share, for a total consideration of $14,971, net of costs.
	The Series A-3 Preferred had the following rights and preferences:
	Dividends — No dividends will be paid on the Series A-3 Preferred unless dividends are paid on common stock.
	Liquidation — Before any payment to the common stockholders, the Series A-3 Preferred holders will receive their liquidation preference.
	In the event of liquidation that values 100% of the equity securities of the Company on a fully-diluted basis at an amount that is equal to or greater than the Series A-3 liquidation amount, as defined, the holders of shares of Series A-3 Preferred shall be entitled to receive their pro rata portion based on the per share amount available to common stockholders.
	If the assets distributable to the holders of the Series A Preferred upon a liquidation are insufficient to pay the full Series A-1, A-2 and A-3 Preferred liquidation amounts, then such assets or the proceeds shall be distributed among the holders of the Series A-1, A-2 and A-3 Preferred ratably in proportion to the respective amount to which they otherwise would be entitled.
	The liquidation amount is equal to the carrying value for all periods presented.
	Voting — Each holder of a Series A-3 Preferred shall be entitled to voting rights and powers equal to the voting rights and powers of common stock (except as otherwise expressly provided or as required by law) voting together with the common stock as a single class on an as-converted to common stock basis. Each share of Series A-3 Preferred (including fractional shares) shall be entitled to one vote for each whole share of common stock that would be issuable upon conversion of such shares on the record date for determining eligibility to participate in the action being taken.
	Conversion rights — Any holder of Series A-3 Preferred may convert any share of Series A-3 Preferred held by such holder into a number of shares of common stock determined by dividing (i) the Series A-3 Preferred purchase price ($51.85 per share) by (ii) the Series A-3 conversion price then in effect. The initial conversion price for the Series A-3 Preferred (the “Series A-3 Conversion Price”) shall be equal to the purchase price ($51.85 per share). The Series A-3 Conversion Price from time in effect is subject to adjustment, as defined. Each share of Series A-3 Preferred shall automatically be converted into shares of common stock at the then effective applicable Series A-3 Conversion Price upon the earliest of (i) the date specified by vote or written consent or agreement of holders of at least a majority of the shares of Series A-3 Preferred then outstanding, (ii) effective immediately before a qualified public offering, as defined, or (iii) effective upon the closing of a liquidation or a reorganization event, as defined.
	Registration Rights — The holders of at least a majority of the Series A-3 Preferred holders, may, by written request, require the Company to file a registration statement with certain limitations.
	Treasury Stock — During the years ended December 31, 2014 and 2012, the Company issued treasury stock in connection with acquisitions completed in 2014 and 2012 (See Note 2). During 2012, the Company retired 38,792 shares of its treasury stock.

STOCKBASED_COMPENSATION

STOCK-BASED COMPENSATION	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION
	The following costs related to the Company’s stock compensation plans were included in the consolidated statements of income and comprehensive income:
			For the Years Ended December 31,
			2014				2013				2012
	Cost of revenues		$	8,648			$	4,823			$	2,809
	Selling, general and administrative expenses		15,972				8,327				4,017
	Total		$	24,620			$	13,150			$	6,826
	Equity Plans
	During the second quarter of 2013, the Company finalized the fair values of the net assets acquired from Empathy Lab. As a result, the Company issued an additional 1,483 shares of unvested (“restricted”) common stock to the sellers of Empathy Lab on July 11, 2013 to settle the difference between the initial number of shares issued upon acquisition and the total number of shares due in connection with this transaction. The shares vest 33.33% on each of the first, second and third anniversaries of the closing date. Upon termination of the recipient’s services with the Company with Cause or without Good Reason (in each case, as defined in the escrow agreement), any unvested shares will be forfeited. The fair value of the restricted shares at the time of grant was $42.
	2012 Non-Employee Directors Compensation Plan — On January 11, 2012, the Company approved the 2012 Non-Employee Directors Compensation Plan (“2012 Directors Plan”) to be used to issue equity grants to its non-employee directors. The Company authorized 600,000 shares of common stock to be reserved for issuance under the plan. The 2012 Directors Plan will expire after 10 years and is administered by the Company’s Board of Directors.
	2012 Long-Term Incentive Plan — On January 11, 2012, the Company approved the 2012 Long-Term Incentive Plan (“2012 Plan”) to be used to issue equity grants to company personnel. As of December 31, 2014, 4,785,761 shares of common stock remained available for issuance under the 2012 Plan. This includes (i) any shares that were available for issuance under the 2006 Plan (as defined below) as of its discontinuance date and that became available for issuance under the 2012 Plan and (ii) any shares that were subject to outstanding awards under the 2006 Plan and have expired or terminated or were cancelled between the discontinuance date of the 2006 Plan and December 31, 2014 and therefore became available for issuance under the 2012 Plan. In addition, up to 1,743,034 shares that are subject to outstanding awards as of December 31, 2014 under the 2006 Plan and that expire or terminate for any reason prior to exercise or that would otherwise have returned to the 2006 Plan’s share reserve under the terms of the 2006 Plan will be available for awards to be granted under the 2012 Plan.
	2006 Stock Option Plan — Effective May 31, 2006, the Board of Directors of the Company adopted the 2006 Stock Option Plan (the “2006 Plan”). The 2006 Plan permitted the granting of options to directors, employees, and certain independent contractors. The Compensation Committee of the Board of Directors generally had the authority to select individuals who were to receive options and to specify the terms and conditions of each option so granted, including the number of shares covered by the option, the exercise price, vesting provisions, and the overall option term. In January 2012, the 2006 Plan was discontinued; however, outstanding awards remain subject to the terms of the 2006 Plan and any shares that are subject to an option award that was previously granted under the 2006 Plan and that will expire or terminate for any reason prior to exercise will become again available for issuance under the 2012 Plan. All of the options issued pursuant to the 2006 Plan expire 10 years from the date of grant.
	Stock Options
	Stock option activity under the Company’s plans is set forth below:
		Number of			Weighted Average				Aggregate
		Options			Exercise Price				Intrinsic Value
	Options outstanding at January 1, 2012	6,595,136			$	4.65			$	48,447
	Options granted	1,443,810			16.8				1,877
	Options exercised	(1,552,742	)		3.53				(22,623		)
	Options forfeited/cancelled	(189,495	)		11.35				(1,279		)
	Options outstanding at December 31, 2012	6,296,709			$	7.51			$	66,682
	Options granted	1,987,952			23.6				22,543
	Options exercised	(2,156,898	)		4.31				(66,066		)
	Options forfeited/cancelled	(304,227	)		11.5				(7,131		)
	Options outstanding at December 31, 2013	5,823,536			$	13.99			$	122,003
	Options granted	2,400,500			32.51				36,584
	Options exercised	(1,171,097	)		9.05				(45,321		)
	Options forfeited/cancelled	(214,193	)		25.33				(4,802		)
	Options outstanding at December 31, 2014	6,838,746			$	20.98			$	183,073
	Options vested and exercisable at December 31, 2014	2,406,016			$	9.83			$	91,236
	Options expected to vest	4,074,226			$	26.82			$	85,274
	The fair value of each option award is estimated on the date of grant using the Black-Scholes option valuation model. The Company recognizes the fair value of each option as compensation expense ratably using the straight-line method over the service period (generally the vesting period). The Black-Scholes model incorporates the following assumptions:
	a. Expected volatility — the Company estimated the volatility of its common stock at the date of grant using historical volatility of peer public companies for the year ended December 31, 2011. In order to compare volatilities for different interval lengths, the Company expresses volatility in annual terms. The Company applied the same approach regarding the stock options issued in 2014 and 2013 due to insufficiency of historical volatility data of its stock prices at the time of grant. The expected volatility was 46% in the year ended December 31, 2014, 2013 and 2012.
	b. Expected term — the Company estimates the expected term of options granted using the simplified method of determining expected term as outlined in SEC Staff Accounting Bulletin 107 as used for grants. The expected term was 6.20 years in 2014, 6.24 years in 2013, and 6.25 years in 2012.
	c. Risk-free interest rate — the Company estimates the risk-free interest rate using the U.S. Treasury yield curve for periods equal to the expected term of the options in effect at the time of grant. The risk-free rate was approximately 2.01%, 1.41% and 1.13% in 2014, 2013 and 2012, respectively.
	d. Dividends — the Company uses an expected dividend yield of zero since it has never declared or paid any dividends on its common stock. The Company intends to retain any earnings to fund future growth and the operation of its business and, therefore, does not anticipate paying any cash dividends in the foreseeable future.
	Additionally, the Company estimates forfeitures at the time of grant and revises those estimates in subsequent periods if actual forfeitures differ from those estimates. It uses a combination of historical data and other factors to estimate pre-vesting option forfeitures and record share-based compensation expense only for those awards that are expected to vest.
	Aggregate grant-date fair value of stock options issued under the 2012 Plan during the year ended December 31, 2014 was $33,004. The options typically vest over four years from the time of grant.
	As of December 31, 2014, a total of 1,554 shares underlying options exercised through December 31, 2014, were in transfer with the Company’s transfer agent.
	As of December 31, 2014, total remaining unrecognized compensation cost related to unvested stock options, net of forfeitures, was approximately $41,669, and is expected to be recognized over a weighted-average period of 1.9 years. The weighted average remaining contractual term of the outstanding options as of December 31, 2014 was 5.1 years for fully vested and exercisable options and 8.6 years for options expected to vest, respectively.
	Other Awards
	Other awards include awards of restricted stock and restricted stock units (“RSUs”) under the Company’s 2012 Directors Plan and 2012 Plan, as well as certain other individual awards. In addition, the Company has in the past, and may in the future, issue its equity securities to compensate employees of acquired businesses for future services, upon such terms and at such prices as it deems appropriate. Equity-based awards granted in connection with acquisitions of businesses are generally issued in the form of service-based awards and performance-based awards. The awards issued in connection with acquisitions of businesses are subject to the terms and conditions contained in the applicable award agreement and acquisition documents. Summarized activity related to the Company’s service-based awards for the years ended December 31, 2014, 2013 and 2012 was as follows:
		Number of			Weighted Average Grant Date
		Shares			Fair Value Per Share
	Unvested service-based awards outstanding at January 1, 2012	—			$	—
	Awards granted	757,272			17.15
	Awards vested	(97,400	)		12
	Unvested service-based awards outstanding at December 31, 2012	659,872			$	17.92
	Awards granted	15,524			23.69
	Awards vested	(330,468	)		17.33
	Unvested service-based awards outstanding at December 31, 2013	344,928			$	18.74
	Awards granted	523,220			40.41
	Awards vested	(217,668	)		17.84
	Awards forfeited/cancelled	(17,038	)		21.14
	Unvested service-based awards outstanding at December 31, 2014	633,442			$	36.88
	For the year ended December 31, 2014, the Company issued a total of 7,738 shares of unvested (“restricted”) common stock under its 2012 Non-Employee Directors Compensation Plan with an aggregate grant date fair value of $325. As of December 31, 2014, aggregate unrecognized compensation expense was $282. This cost is expected to be recognized over the next 1.6 years using the weighted average method.
	For the year ended December 31, 2014, the Company issued a total of 70,500 RSUs to certain key management personnel under the 2012 Plan. The fair value of the RSUs at the time of the grants was $2,295. As of December 31, 2014, the aggregate unrecognized compensation expense for these RSUs was $1,643. This cost is expected to be recognized over the next 2.2 years using the weighted average method.
	For the year ended December 31, 2014, the Company granted a total of 444,982 service-based awards in connection with the acquisitions of businesses completed during that period. The aggregate grant date fair value of the awards was $18,471. As of December 31, 2014, a total of 545,379 shares underlying service-based awards with an aggregate fair value of $20,544 were unvested and outstanding in connection with the Company’s acquisitions activity. This cost is expected to be recognized over the next 1.7 years using the weighted average method.
	During the year ended December 31, 2014, the Company initiated granting performance-based awards in connection with the acquisitions completed during that period. Total number of the awards varies based on attainment of certain performance targets pursuant to provisions of the relevant purchase agreements. Typically, the performance period is three years, with one third of the awards granted, vesting on the first anniversary of the grant. The remaining awards vest in equal installments on the second and third anniversaries of the grant. If an eligible employee leaves the Company prior to a vesting date, the unvested portion of the award will be forfeited, generally. The Company periodically evaluates the achievement of the related performance conditions during requisite service period and the number of shares expected to be delivered, and resulting compensation expense is adjusted accordingly.
	Summarized activity related to the Company’s performance-based awards for the years ended December 31, 2014, was as follows:
		Number of Shares			Weighted Average Grant Date Fair Value Per Share
	Unvested performance-based awards outstanding at December 31, 2013	—			$	—
	Awards granted	387,058			38.18
	Awards vested	—			—
Awards forfeited/cancelled	(2,550	)		36.57
Changes in the number of awards expected to be delivered	(12,998	)		5.47
Unvested performance-based awards outstanding at December 31, 2014	371,510			$	39.34
As of December 31, 2014, total unrecognized compensation cost related to unvested performance-based awards was $13,953. That cost is expected to be recognized over the next 1.8 years using the weighted average method.

EARNINGS_PER_SHARE

EARNINGS PER SHARE	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
EARNINGS PER SHARE
		EARNINGS PER SHARE
	Basic earnings per share ("EPS") is computed by dividing the net income applicable to common stockholders for the period by the weighted average number of shares of common stock outstanding during the same period. Our Series A-1 Preferred, Series A-2 Preferred, Series A-3 Preferred, and restricted stock units were considered participating securities since these securities had non-forfeitable rights to dividends or dividend equivalents during the contractual period of the award and thus required the two-class method of computing EPS. When calculating diluted EPS, the numerator is computed by adding back the undistributed earnings allocated to the participating securities in arriving at the basic EPS and then reallocating such undistributed earnings among the company’s common stock, participating securities and the potential common shares that result from the assumed exercise of all dilutive options. The denominator is increased to include the number of additional common shares that would have been outstanding had the options been issued.
	The following table sets forth the computation of basic and diluted earnings per share of common stock as follows:
			For the Years Ended December 31,
			2014		2013		2012
	Numerator for common earnings per share:
	Net income		$	69,641	$	61,994	$	54,484
	Net income allocated to participating securities		—		—		(3,341		)
	Numerator for basic earnings per share		69,641		61,994		51,143
	Effect on income available from reallocation of options		—		—		261
	Numerator for diluted earnings per share		$	69,641	$	61,994	$	51,404
	Denominator for basic earnings per share:
	Weighted average common shares outstanding		47,189		45,754		40,190
	Effect of dilutive securities:
	Stock options, RSUs and performance-based awards		2,545		2,604		3,631
	Denominator for diluted earnings per share		49,734		48,358		43,821
	Net income per share:
	Basic		$	1.48	$	1.35	$	1.27
	Diluted		$	1.4	$	1.28	$	1.17
	For the years ended December 31, 2014, 2013 and 2012 a total of 2,260, 1,080 and 1,534 shares underlying equity-based awards, respectively, were outstanding but were not included in the computation of diluted earnings per share because the effect was anti-dilutive.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES
	The Company leases office space under operating leases, which expire at various dates through 2019. Certain leases contain renewal provisions and generally require the Company to pay utilities, insurance, taxes, and other operating expenses. Rent expense under operating lease agreements for the years ended December 31, 2014, 2013 and 2012 was $18,200, $15,664, and $11,594 respectively. Future minimum rental payments under operating leases that have initial or remaining lease terms in excess of one year as of December 31, 2014 were as follows:
	Year Ending December 31,	Operating Leases
	2015	$	16,718
	2016	10,482
	2017	7,668
	2018	4,993
	2019	3,589
	Thereafter	952
	Total minimum lease payments	$	44,402
	Construction in progress — On December 7, 2011, the Company entered into an agreement with IDEAB Project Eesti AS (“IDEAB”) for the construction of an office building within the High Technologies Park in Minsk, Belarus (the “Construction Agreement”). At the same time, the Company entered into a related investment agreement with the Minsk Executive Committee acting on behalf of the Republic of Belarus (the “Investment Agreement”) permitting the Company to use land located in the government’s High Technologies Park to construct the new office building and granting certain tax benefits. The Investment Agreement specified a completion deadline for construction of September 15, 2012 extended by the parties to December 31, 2014, the Company is negotiating a further extension to July 1, 2015. Per the Investment Agreement, if the Company does not meet the completion deadline, monthly penalties may be imposed; the most recent extension of the Investment Agreement increases the monthly penalty to $20 per month for the period beginning January 1, 2015. There may be further terms and conditions imposed on the Company in a further extension of the Investment Agreement. If the Investment Agreement is terminated, the Company could be required to disgorge certain tax benefits received by the Company in connection with the project and could potentially be required to fully restore the land to its original condition. The Company has not been required to pay any penalties to date. The Company has secured the required building construction permits and is working toward completion of the building. The Company believes that the building will be completed and available for its use in 2015, and that any penalties or loss of tax benefits will not be material to the accompanying financial statements.
	The Construction Agreement committed IDEAB to construct an office building for the Company in Minsk with a committed completion date of February 28, 2014. In April 2014 IDEAB stopped its construction before the building’s completion, for reasons unrelated to the Company’s performance under the Construction Agreement. In May 2014, IDEAB notified the Company that it was unable to continue as general contractor to complete the construction of the building in time and on the terms agreed. As a result, the Company took control over the construction site. On July 7, 2014, the Company provided IDEAB with notice of termination of the Construction Agreement, effective on or about July 11, 2014. The Company filed a legal action against IDEAB in Belarus in August 2014, claiming breach of contract. In September 2014, the court decided in the Company’s favor and directed IDEAB to pay the Company $1,000 plus reimbursement of certain expenses. The Company is pursuing recovery from IDEAB of this amount. The Company has filed other lawsuits seeking recovery from IDEAB of additional amounts (including future work and construction materials) from IDEAB. These lawsuits are in various stages of litigation and it is not possible to estimate the likelihood of recovery.
	At December 31, 2014, the Company had approximately $17,885 of capitalized construction costs and estimated up to $8.2 million of additional investment required to complete the construction and put the building into operation. The Company estimates that the building construction will be completed by June 30, 2015. In addition, up to $4,500 of advance payments issued to IDEAB for future work and construction materials under the Construction Agreement may not be recoverable. As of December 31, 2014, the Company estimated the amount of probable losses under the Construction Agreement at $2,593. These costs were recorded within the Company’s consolidated income from operations during the year ended December 31, 2014.
	Based on the information known to the Company at this time, any additional liability related to this matter is not reasonably estimable.
	Indemnification Obligations — In the normal course of business, the Company is a party to a variety of agreements under which it may be obligated to indemnify the other party for certain matters. These obligations typically arise in contracts where the Company customarily agrees to hold the other party harmless against losses arising from a breach of representations or covenants for certain matters such as title to assets and intellectual property rights associated with certain arrangements. The duration of these indemnifications varies, and in certain cases, is indefinite.
	The Company is unable to reasonably estimate the maximum potential amount of future payments under these or similar agreements due to the unique facts and circumstances of each agreement and the fact that certain indemnifications provide for no limitation to the maximum potential future payments under the indemnification. Management is not aware of any such matters that historically had or would have a material effect on the financial statements of the Company.
	Litigation — From time to time, the Company is involved in litigation, claims or other contingencies. Management is not aware of any such matters that would have a material effect on the consolidated financial statements of the Company.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS
	As required by the guidance for fair value measurements, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. Thus, assets and liabilities categorized as Level 3 may be measured at fair value using inputs that are observable (Levels 1 and 2) and unobservable (Level 3). Significant unobservable inputs used in the fair value measurement of contingent consideration related to business acquisitions are forecasts of expected future operating results of those businesses as developed by the Company’s management and the probability of achievement of those operating forecasts. Management’s assessment of the significance of a particular input to the fair value measurement requires judgment and may affect the valuation of assets and liabilities and their placement within the fair value hierarchy levels.
	The following table represents the Company’s fair value hierarchy for its financial assets as of December 31, 2014 and 2013.
			As of December 2014
			Balance			Level 1		Level 2		Level 3
	Cash and cash equivalents		$	220,534		$	220,534	$	—	$	—
	Time deposits and restricted cash		156			—		156		—
	Employee loans		6,515			—		—		6,515
	Total assets measured at fair value on recurring basis		$	227,205		$	220,534	$	156	$	6,515
			As of December 2013
			Balance			Level 1		Level 2		Level 3
	Cash and cash equivalents		$	169,207		$	169,207	$	—	$	—
	Time deposits and restricted cash		1,711			—		1,711		—
	Employee loans		6,390			—		—		6,390
	Total assets measured at fair value on recurring basis		$	177,308		$	169,207	$	1,711	$	6,390
	During the years ended December 31, 2014 and 2013, the Company issued a total of $3,162 and $8,963 of loans to its employees, respectively, and received $3,025 and $3,088 in loan repayments during the same periods, respectively.
	During the years ended December 31, 2014 and 2013, there were no transfers amongst Level 1, Level 2, or Level 3 financial assets and liabilities.
	The following tables show the fair values of the Company’s financial liabilities measured at fair value on a recurring basis:
		As of December 31, 2014
		Balance			Level 3
	Contingent consideration	$	37,400		$	37,400
	Performance-based equity awards	3,223			3,223
	Total liabilities measured at fair value on a recurring basis	$	40,623		$	40,623
	There were no liabilities measured at fair value on a recurring basis as of December 31, 2013.
	As of December 31, 2014, contingent consideration and performance-based equity awards included amounts payable in cash and stock in connection with the acquisitions of businesses completed in the year ended December 31, 2014 (Note 2).
	Sensitivity to Changes in Significant Unobservable Inputs
	The fair value of the contingent consideration is based on the present value of the expected future payments to be made to the sellers of the acquired businesses in accordance with the provisions outlined in the respective purchase agreements. In determining fair value, the Company considered a variety of factors, including third party valuation experts and future performance of the acquired businesses using financial projections developed by the Company and market risk assumptions that were derived for revenue growth and/or earnings before interest, tax, and depreciation and amortization (“EBITDA”). The Company estimated future payments using the earnout formula and performance targets specified in each purchase agreement and adjusted those estimates to reflect the ability of the acquired entities to achieve the targets. It then discounted the payments to present value using the Company’s cost of debt for the cash component, and a risk-free rate for the stock component of the earnout for all of the Company’s 2014 acquisitions. Changes in financial projections, market risk assumptions for revenue growth and/or EBITDA, or the discount rates, would result in a change in the fair value of recorded contingent liabilities. In addition, inputs used in the valuation of the stock component of the earnout include term, stock price volatility, current stock price, and exercise price, with the Company current stock price factor being the input subject to the most variation. A significant increase in the Company stock price, in isolation, would result in a significantly higher fair value measurement. As the Company’s common stock does not have sufficient trading history, volatility was determined by measuring the volatility of a representative group of its peers, in conjunction with the volatility of the Company’s available trading history.
	A reconciliation of the beginning and ending balances of acquisition-related contractual contingent liabilities using significant unobservable inputs (Level 3) for the year ended December 31, 2014 , was as follows:
		Amount
	Contractual contingent liabilities at January 1, 2014	$	—
	Acquisition date fair value of contractual contingent liabilities — Netsoft	1,825
	Acquisition date fair value of contractual contingent liabilities — Jointech	20,000
	Acquisition date fair value of contractual contingent liabilities — GGA	11,400
	Acquisition date fair value of contractual contingent liabilities — Great Fridays	1,173
	Liability-classified stock-based awards	3,088
	Changes in fair value of contractual contingent liabilities included in earnings	2,059
	Changes in fair value of contractual contingent liabilities recorded against goodwill	1,366
	Effect of net foreign currency exchange rate changes	(288		)
	Contractual contingent liabilities at December 31, 2014	$	40,623
	There were no transfers in or out of Level 3 from other levels in the fair value hierarchy during the years ended December 31, 2014 and 2013. Changes in the values of the financial liabilities, if any, are recorded within other expense (income) in operating income on the Company’s consolidated statements of income and comprehensive income.

OPERATING_SEGMENTS

OPERATING SEGMENTS	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
OPERATING SEGMENTS
		OPERATING SEGMENTS
	The Company determines its operating segments and reports segment information in accordance with the management approach, which designates internal reporting used by management to make operating decisions and assess performance as the source of the Company’s reportable segments.
	The Company manages its business primarily based on the geographic managerial responsibility for its client base. As managerial responsibility for a particular client relationship generally correlates with the client’s geographic location, there is a high degree of similarity between client locations and the geographic boundaries of the Company’s reportable segments. In some cases, managerial responsibility for a particular client is assigned to a management team in another region and is usually based on the strength of the relationship between client executives and particular members of EPAM’s senior management team. In such a case, the client’s activity would be reported through the management team’s reportable segment.
	The Company’s reportable segments are North America, Europe, Russia and Other. The Company’s Chief Operating Decision Maker (“CODM”) evaluates performance and allocates resources based on the segment's revenues and operating profit. Segment operating profit is defined as income from operations before unallocated costs. Generally, operating expenses for each operating segment have similar characteristics and are subject to similar factors, pressures and challenges. Expenses included in segment operating profit consist principally of direct selling and delivery costs as well as an allocation of certain shared services expenses. Certain expenses, such as stock-based compensation are not allocated to specific segments, as management does not believe it is practical as these expenses are not directly attributable to any specific segment and consequently are not allocated to individual segments in internal management reports used by the CODM. Such expenses are separately disclosed as “unallocated” and adjusted only against the Company’s total income from operations.
	Revenues from external customers and segment operating profit, before unallocated expenses, for the North America, Europe, Russia and Other reportable segments were as follows:
			For the years ended December 31,
			2014				2013			2012
	Total segment revenues:
	North America		$	374,509			$	284,636		$	197,271
	Europe		299,279				204,150			168,913
	Russia		50,663				55,764			50,552
	Other		5,552				10,493			16,986
	Total segment revenues		$	730,003			$	555,043		$	433,722
	Segment operating profit:
	North America		$	90,616			$	66,814		$	38,671
	Europe		50,189				34,573			32,750
	Russia		7,034				7,077			9,049
	Other		(3,220		)		844			6,985
	Total segment operating profit		$	144,619			$	109,308		$	87,455
	Intersegment transactions were excluded from the above on the basis that they are neither included into the measure of a segment’s profit and loss by the CODM, nor provided to the CODM on a regular basis.
	During the year ended December 31, 2014, revenues from one customer, UBS AG, were $97,872 and accounted for more than 10% of total revenues. Revenue from this customer is reported in the Company’s Europe segment and includes reimbursable expenses.
	Trade accounts receivable and unbilled revenues are generally dispersed across our clients in proportion to their revenues. There were no customers individually exceeding 10% of our trade receivables billed as of December 31, 2014. As of December 31, 2014, unbilled trade receivables from one customer, UBS AG, individually exceeded 10% and accounted for 16.5% of our total unbilled trade receivables as of that date.
	Reconciliation of segment revenues and operating profit to consolidated income before provision for income taxes is presented below:
			For the Years Ended December 31,
			2014				2013			2012
	Total segment revenues		$	730,003			$	555,043		$	433,722
	Unallocated revenue		24				74			77
	Revenues		$	730,027			$	555,117		$	433,799
	Total segment operating profit:		$	144,619			$	109,308		$	87,455
	Unallocated amounts:
	Other revenues		24				74			77
	Stock-based compensation expense		(24,620		)		(13,150		)	(6,826		)
	Non-corporate taxes		(6,882		)		(3,201		)	(2,346		)
	Professional fees		(5,312		)		(3,651		)	(2,850		)
	Depreciation and amortization		(7,988		)		(2,829		)	(1,100		)
	Bank charges		(1,049		)		(1,194		)	(1,136		)
	Asset impairment		(5,983		)		—			—
	Stock charge		—				—			(640		)
	Provision for bad debts		—				(36		)	—
	Other corporate expenses		(6,626		)		(8,828		)	(6,628		)
	Income from operations		86,183				76,493			66,006
	Interest and other income, net		4,769				3,077			1,941
	Change in fair value of contingent consideration		(1,924		)		—			—
	Foreign exchange loss		(2,075		)		(2,800		)	(2,084		)
	Income before provision for income taxes		$	86,953			$	76,770		$	65,863
	Geographic Area Information
	Long-lived assets include property and equipment, net of accumulated depreciation and amortization, and management has determined that it is not practical to allocate these assets by segment since such assets are used interchangeably among the segments. Geographical information about the Company’s long-lived assets based on physical location of the assets was as follows:
		December 31,				December 31,
		2014				2013
	Belarus	$	41,652			$	38,697
	Ukraine	4,392				5,525
	Hungary	2,773				2,644
	Russia	2,196				3,414
	United States	2,001				2,217
	Other	2,120				818
	Total	$	55,134			$	53,315
	Information about the Company’s revenues by client location is as follows:
			For the Years Ended December 31,
			2014				2013			2012
	United States		$	318,304			$	247,979		$	197,593
	United Kingdom		141,366				108,892			98,346
	Switzerland		87,111				51,941			30,120
	Russia		48,945				53,328			47,507
Canada		49,193				33,759			9,256
Germany		25,740				20,261			16,391
China		13,445				—			—
Netherlands		8,838				7,719			3,127
Sweden		7,892				5,742			4,913
Kazakhstan		5,238				9,886			11,352
Other locations		15,545				7,984			8,777
Reimbursable expenses and other revenues		8,410				7,626			6,417
Revenues		$	730,027			$	555,117		$	433,799
Service Offering Information
Information about the Company’s revenues by service offering is as follows:
		For the Years Ended December 31,
		2014				2013			2012
Software development		$	504,590			$	374,426		$	290,139
Application testing services		140,363				109,222			85,849
Application maintenance and support		58,840				45,971			36,056
Infrastructure services		14,198				14,433			12,424
Licensing		3,626				3,439			2,914
Reimbursable expenses and other revenues		8,410				7,626			6,417
Revenues		$	730,027			$	555,117		$	433,799

QUARTERLY_FINANCIAL_DATA

QUARTERLY FINANCIAL DATA	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
QUARTERLY FINANCIAL DATA	QUARTERLY FINANCIAL DATA (UNAUDITED)
	Summarized quarterly results for the two years ended December 31, 2014 and 2013 were as follows:
			Three Months Ended
	2014		March 31			June 30			September 30			December 31			Full Year
	Revenues		$	160,384		$	174,695		$	192,764		$	202,184		$	730,027
	Operating expenses:
	Cost of revenues (exclusive of depreciation and amortization)		102,454			110,102			122,509			121,465			456,530
	Selling, general and administrative expenses		32,359			38,671			42,875			49,761			163,666
	Depreciation and amortization expense		3,689			5,451			5,510			2,833			17,483
	Goodwill impairment loss		—			—			—			2,241			2,241
	Other operating (income)/ expenses, net		25			1,995			35			1,869			3,924
	Income from operations		21,857			18,476			21,835			24,015			86,183
	Interest and other income, net		976			1,164			1,261			1,368			4,769
	Change in fair value of contingent consideration		—			—			—			(1,924		)	(1,924		)
	Foreign exchange loss		(1,241		)	(1,239		)	(718		)	1,123			(2,075		)
	Income before provision for income taxes		21,592			18,401			22,378			24,582			86,953
	Provision for income taxes		4,228			3,587			3,338			6,159			17,312
	Net income		$	17,364		$	14,814		$	19,040		$	18,423		$	69,641
	Comprehensive income		$	13,787		$	17,708		$	10,780		$	7,115		$	49,390
	Basic net income per share(1)		$	0.37		$	0.31		$	0.4		$	0.39		$	1.48
	Diluted net income per share(1)		$	0.35		$	0.3		$	0.38		$	0.37		$	1.4
	-1	Earnings per share amounts for each quarter may not necessarily total to the yearly earnings per share due to the weighting of shares outstanding on a quarterly and year to date basis.
			Three Months Ended
	2013		March 31			June 30			September 30			December 31			Full Year
	Revenues		$	124,198		$	133,184		$	140,150		$	157,585		$	555,117
	Operating expenses:
	Cost of revenues (exclusive of depreciation and amortization)		77,937			83,547			88,539			97,627			347,650
	Selling, general and administrative expenses		27,083			28,541			27,893			32,980			116,497
	Depreciation and amortization expense		3,617			3,854			3,906			3,743			15,120
	Goodwill impairment loss		—			—			—			—			—
	Other operating (income)/ expenses, net		25			(293		)	(418		)	43			(643		)
	Income from operations		15,536			17,535			20,230			23,192			76,493
	Interest and other income, net		630			769			846			832			3,077
	Change in fair value of contingent consideration		—			—			—			—			—
	Foreign exchange loss		(499		)	(869		)	(720		)	(712		)	(2,800		)
	Income before provision for income taxes		15,667			17,435			20,356			23,312			76,770
	Provision for income taxes		2,987			3,317			3,919			4,553			14,776
	Net income		$	12,680		$	14,118		$	16,437		$	18,759		$	61,994
	Comprehensive income		$	10,337		$	13,073		$	19,412		$	18,361		$	61,183
	Basic net income per share(1)		$	0.28		$	0.31		$	0.36		$	0.4		$	1.35
	Diluted net income per share(1)		$	0.27		$	0.29		$	0.34		$	0.38		$	1.28
	-1	Earnings per share amounts for each quarter may not necessarily total to the yearly earnings per share due to the weighting of shares outstanding on a quarterly and year to date basis.

NATURE_OF_BUSINESS_AND_SIGNIFI1

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Nature of Operations	EPAM is a leading global provider of complex software engineering solutions and information technology ("IT") services to clients throughout North America, Western and Eastern Europe, Russia and Asia. The Company serves primarily Fortune Global 2000 companies in various industries with the main focus on Independent Software Vendors (“ISVs”) and technology, banking and financial services, business information and media, and travel and hospitality. Other industries include retail, energy, life sciences, healthcare, telecommunications, and government.
	Since EPAM’s inception in 1993, the Company has focused on providing software product development services, software engineering and vertically-oriented custom development solutions through its global delivery model. This has served as a foundation for the Company’s other solutions, including custom application development, application testing, platform-based solutions, application maintenance and support, and infrastructure management.
	The Company is incorporated in Delaware with headquarters in Newtown, PA, with multiple delivery centers located in Belarus, Ukraine, Russia, Hungary, Kazakhstan, Bulgaria, China, Armenia and Poland, and client management locations in the United States, Canada, the United Kingdom, Germany, Sweden, Switzerland, Netherlands, Russia, Kazakhstan, Singapore, Hong Kong and Australia.
Emerging Growth Company Status	Emerging growth company status — In April 2012, several weeks after EPAM’s initial public offering in February 2012, President Obama signed into law the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”). The JOBS Act contains provisions that relax certain requirements for “emerging growth companies” that otherwise apply to larger public companies. For as long as a company retains emerging growth company status, it will not be required to (1) provide an auditor’s attestation report on the Company’s internal control over financial reporting, otherwise required by Section 404(b) of the Sarbanes-Oxley Act of 2002, (2) comply with any new or revised financial accounting standard applicable to public companies until such standard is also applicable to private companies, (3) comply with certain new requirements adopted by the Public Company Accounting Oversight Board, (4) provide certain disclosure regarding executive compensation required of larger public companies or (5) hold shareholder advisory votes on matters relating to executive compensation. Based on EPAM's market capitalization on June 30, 2014, it was deemed a large accelerated filer as of December 31, 2014. Therefore, EPAM no longer qualifies as an emerging growth company.
Principles of Consolidation	Principles of Consolidation — The consolidated financial statements include the financial statements of EPAM Systems, Inc. and its subsidiaries. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates — The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions. These estimates and assumptions affect reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as revenues and expenses during the reporting period. The Company bases its estimates and judgments on historical experience, knowledge of current conditions and its beliefs of what could occur in the future, given available information. Actual results could differ from those estimates, and such differences may be material to the financial statements.
Revenue Recognition	Revenue Recognition — The Company recognizes revenue when realized or realizable and earned, which is when the following criteria are met: persuasive evidence of an arrangement exists; delivery has occurred; the sales price is fixed or determinable; and collectability is reasonably assured. Determining whether and when some of these criteria have been satisfied often involves assumptions and judgments that can have a significant impact on the timing and amount of revenue we report. If there is an uncertainty about the project completion or receipt of payment for the services, revenues are deferred until the uncertainty is sufficiently resolved. At the time revenues are recognized, the Company provides for any contractual deductions and reduces revenues accordingly. The Company defers amounts billed to its clients for revenues not yet earned. Such amounts are anticipated to be recorded as revenues as services are performed in subsequent periods. Unbilled revenues represent services provided which are billed subsequent to the period end in accordance with the contract terms.
	The Company derives its revenues from a variety of service offerings, which represent specific competencies of its IT professionals. Contracts for these services have different terms and conditions based on the scope, deliverables, and complexity of the engagement, which require management to make judgments and estimates in determining appropriate revenue recognition pattern. Fees for these contracts may be in the form of time-and-materials or fixed-price arrangements.
	The majority of the Company’s revenues (84.7% of revenues in 2014, 82.3% in 2013 and 84.1% in 2012) is generated under time-and-material contracts whereby revenues are recognized as services are performed with the corresponding cost of providing those services reflected as cost of revenues when incurred. The majority of such revenues are billed on an hourly, daily or monthly basis whereby actual time is charged directly to the client.
	Revenues from fixed-price contracts (13.6% of revenues in 2014, 15.7% in 2013 and 13.7% in 2012) are determined using the proportional performance method. In instances where final acceptance of the product, system, or solution is specified by the client, revenues are deferred until all acceptance criteria have been met. In absence of a sufficient basis to measure progress towards completion, revenue is recognized upon receipt of final acceptance from the client. In order to estimate the amount of revenue for the period under the proportional performance method, the Company determines the percentage of actual labor hours incurred as compared to estimated total labor hours and applies that percentage to the consideration allocated to the deliverable. The complexity of the estimation process and factors relating to the assumptions, risks and uncertainties inherent with the application of the proportional performance method of accounting affects the amounts of revenues and related expenses reported in the Company’s consolidated financial statements. A number of internal and external factors can affect such estimates, including labor hours and specification and testing requirement changes. The cumulative impact of any revision in estimates is reflected in the financial reporting period in which the change in estimate becomes known. No significant revisions occurred in each of the three years ended December 31, 2014, 2013 and 2012. The Company’s fixed price contracts are generally recognized over a period of 12 months or less.
	The Company reports gross reimbursable “out-of-pocket” expenses incurred as both revenues and cost of revenues in the consolidated statements of income and comprehensive income.
Cost of Revenues (Exclusive of Depreciation and Amortization)	Cost of Revenues (Exclusive of Depreciation and Amortization) — Consists principally of salaries, employee benefits, stock compensation expense and non-reimbursable travel costs for IT professionals, and subcontractor fees.
Selling, General and Administrative Expenses	Selling, General and Administrative Expenses — Consist of expenses associated with promoting and selling the Company’s services and include such items as the cost of advertising and other promotional activities as well as sales and marketing personnel salaries, stock compensation expense and related fringe benefits, commissions and travel. General and administrative expenses include other operating items such as officers’ and administrative personnel salaries, stock compensation expense and related fringe benefits as well as legal and audit expenses, insurance, provision for doubtful accounts, and operating lease expenses.
Fair Value of Financial Instruments	Fair Value of Financial Instruments — The Company makes significant assumptions about fair values of its financial instruments. Fair value is determined based on the assumptions that market participants would use in pricing the asset or liability. The Company utilizes the following fair value hierarchy in determining fair values:
	Level 1 — Quoted prices for identical assets or liabilities in active markets.
	Level 2 — Inputs other than quoted prices within Level 1 that are observable either directly or indirectly, including quoted prices in markets that are not active, quoted prices in active markets for similar assets or liabilities, and observable inputs other than quoted prices such as interest rates or yield curves.
	Level 3 — Unobservable inputs reflecting our view about the assumptions that market participants would use in pricing the asset or liability.
	Where the fair values of financial assets and liabilities recorded in the consolidated balance sheets cannot be derived from an active market, they are determined using a variety of valuation techniques. These valuation techniques include a net present value technique, comparison to similar instruments with market observable inputs, options pricing models and other relevant valuation models. Inputs into these models are taken from observable market data whenever possible, but in instances where it is not reasonably feasible, a degree of judgment is required to establish fair values.
	Financial Assets and Liabilities Measured At Fair Value on a Recurring Basis
	The Company had no assets or liabilities measured at fair value on a recurring basis as of December 31, 2014 and 2013, other than contingent liabilities in connection with the acquisitions of businesses.
	At December 31, 2014, contingent liabilities measured at fair value on a recurring basis comprised contingent consideration payable in cash and stock, and performance-based awards issued to certain former owners of the acquired businesses in exchange for future services.
	The Company estimates the fair value of contingent liabilities based on certain performance milestones of the acquired businesses, and estimated probabilities of achievement, then discounts the liabilities to present value using the Company’s cost of debt for the cash component of contingent consideration, and risk free rate for the stock component of a contractual contingency. Contingent liabilities are valued using significant inputs that are not observable in the market which are defined as Level 3 inputs pursuant to fair value measurement accounting. The Company believes its estimates and assumptions are reasonable, however, there is significant judgment involved. Changes in the fair value of contingent consideration liabilities primarily result from changes in the timing and amount of specific milestone estimates and changes in probability assumptions with respect to the likelihood of achieving the various earnout criteria. These changes could cause a material impact to, and volatility in the Company’s operating results. See Note 17 for contingent liabilities activity.
	Financial Assets and Liabilities Measured At Fair Value on a Non-Recurring Basis
	The amounts of the Company’s financial assets and liabilities, with the exceptions of employee housing loans and other employee loans described further herein, approximate fair value because of their short-term maturities.
	Employee Housing Loans — The housing loans were classified as Level 3 measurements within the fair value hierarchy because they were valued using significant unobservable inputs. The estimated fair value of these housing loans upon initial recognition was computed by projecting the future contractual cash flows to be received from the loans and discounting those projected net cash flows to a present value, which is the estimated fair value (the “Income Approach”). In applying the Income Approach, the Company analyzed similar loans offered by third-party financial institutions in Belarusian Rubles (“BYR”) and adjusted the interest rates charged on such loans to exclude the effects of underlying economic factors, such as inflation and currency devaluation. The Company also assessed the probability of future defaults and associated cash flows impact. In addition, the Company separately analyzed the rate of return that market participants in Belarus would require when investing in unsecured USD-denominated government bonds with similar maturities (a “risk-free rate”) and evaluated a risk premium component to compensate the market participants for the credit and liquidity risks inherent in the loans’ cash flows. As a result of the analysis performed, the Company determined the carrying values of the housing loans issued during the year ended December 31, 2014 approximated their fair values upon initial recognition. The Company also estimated the fair values of the housing loans that were outstanding as of December 31, 2014 and 2013 using the inputs noted above and determined their fair values approximated the carrying values as of that date.
	Employee Loans, Other — The Company also issues short-term non-interest bearing relocation loans and other employee loans. These loans are considered Level 3 measurements. The Company’s Level 3, unobservable inputs reflect its assumptions about the factors that market participants use in pricing similar receivables, and are based on the best information available in the circumstances. Due to the short-term nature of employee loans (i.e., the relatively short time between the origination of the instrument and its expected realization), the carrying amount is a reasonable estimate of fair value. As of December 31, 2014, the carrying values of these employee loans approximated their fair values.
Business Combinations	Business Combinations — The Company accounts for its business combinations using the acquisition accounting method, which requires it to determine the fair value of net assets acquired and the related goodwill and other intangible assets. The Company identifies and attributes fair values and estimated lives to the intangible assets acquired and allocates the total cost of an acquisition to the underlying net assets based on their respective estimated fair values. Determining the fair value of assets acquired and liabilities assumed requires management’s judgment and involves the use of significant estimates, including projections of future cash inflows and outflows, discount rates, asset lives and market multiples. There are different valuation models for each component, the selection of which requires considerable judgment. These determinations will affect the amount of amortization expense recognized in future periods. The Company bases its fair value estimates on assumptions it believes are reasonable, but recognizes that the assumptions are inherently uncertain.
	If initial accounting for the business combination has not been completed by the end of the reporting period in which the business combination occurs, provisional amounts are reported for which the accounting is incomplete, with retrospective adjustment made to such provisional amounts during the measurement period to present new information about facts and circumstances that existed as of the acquisition date. Once the measurement period ends, and in no case beyond one year from the acquisition date, revisions of the accounting for the business combination are recorded in earnings.
	All acquisition-related costs, other than the costs to issue debt or equity securities, are accounted for as expenses in the period in which they are incurred. Changes in fair value of contingent consideration arrangements that are not measurement period adjustments are recognized in earnings. Payments to settle contingent consideration, if any, are reflected in cash flows from financing activities and the changes in fair value are reflected in cash flows from operating activities in the Company’s consolidated statements of cash flows.
	The Company’s acquisitions usually do not have significant amounts of tangible assets, as the principal assets typically acquired are customer relationships, trade names, non-competition agreements, and workforce. As a result, a substantial portion of the purchase price is allocated to goodwill and other intangible assets.
Cash and Cash Equivalents	Cash and Cash Equivalents — Cash equivalents are short-term, highly liquid investments that are readily convertible into cash, with maturities of three months or less at the date acquired. As of December 31, 2014 and 2013 the Company had no cash equivalents.
Restricted Cash	Restricted Cash — Restricted cash represents cash that is restricted by agreements with third parties for special purposes and includes time deposits. See Note 6 for items that constitute restricted cash.
Accounts Receivable	Accounts Receivable — Accounts receivable are stated net of an allowance for doubtful accounts. Outstanding accounts receivable are reviewed periodically and allowances are provided at such time the management believes it is probable that such balances will not be collected within a reasonable time. The allowance for doubtful accounts is determined by evaluating the relative creditworthiness of each client, historical collections experience and other information, including the aging of the receivables. Accounts receivable are generally written off when they are deemed uncollectible. Bad debts are recorded based on historical experience and management's evaluation of accounts receivable.
Employee Loans	Employee Loans — Loans are initially recorded at their fair value, and subsequently measured at their amortized cost, less allowance for loan losses, if any. The Company intends to hold all employee loans until their maturity. Interest income is reported using the effective interest method. Where applicable, loan origination fees, net of direct origination costs, are deferred and recognized in interest income over the life of the loan.
Property and Equipment	Property and Equipment — Property and equipment acquired in the ordinary course of the Company’s operations are stated at cost, net of accumulated depreciation. Depreciation is calculated on the straight-line basis over the estimated useful lives of the assets generally ranging from three to 50 years. Leasehold improvements are amortized on a straight-line basis over the shorter of the term of the lease or the estimated useful life of the improvement. Maintenance and repairs are expensed as incurred.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets — Goodwill and intangible assets that have indefinite useful lives are treated consistently with ASC 350. They are tested annually for impairment and are not amortized.
	The Company performs an annual impairment test by comparing the respective fair value of its reporting units to their respective carrying values to identify if any impairment indicators exist. If an indicator of impairment is identified, the implied fair value of the reporting unit’s goodwill is compared to its carrying amount, and the impairment loss is measured by the excess of the carrying value over fair value. The fair values are estimated using a combination of the income approach, which incorporates the use of the discounted cash flow method, and the market approach, which incorporates the use of earnings multiples based on market data. These valuations are considered Level 3 measurements under FASB ASC Topic 820. The Company utilizes estimates to determine the fair value of the reporting units such as future cash flows, growth rates, capital requirements, effective tax rates and projected margins, among other factors. Estimates utilized in the future evaluations of goodwill for impairment could differ from estimates used in the current period calculations. The Company is also required to assess the goodwill of its reporting units for impairment between annual assessment dates when events or circumstances dictate.
	Intangible assets that have finite useful lives are amortized over their estimated useful lives on a straight-line basis.
	Effective in the fourth quarter of 2013, the Company changed the annual goodwill impairment assessment date for all of its reporting units from December 31st to October 31st, which represented a voluntary change in the annual goodwill impairment testing date. The Company evaluates the recoverability of goodwill at a reporting unit level and it had three reporting units, which had goodwill, that were subject to the annual impairment testing in 2014.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets — Long-lived assets, such as property and equipment, and finite lived intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable and exceeds the asset's fair value. When the carrying value of an asset is more than the sum of the undiscounted cash flows that are expected to result from the asset's use and eventual disposition, it is considered to be unrecoverable. Therefore, when an asset’s carrying value will not be recovered and it is more than its fair value the Company would deem the asset to be impaired. Property and equipment held for disposal are carried at the lower of the current carrying value or fair value less estimated costs to sell. The Company did not incur any impairment of long-lived assets for the years ended December 31, 2014, 2013 and 2012.
Income Taxes	Income Taxes — The provision for income taxes includes federal, state, local and foreign taxes. Deferred tax assets and liabilities are recognized for the estimated future tax consequences of temporary differences between the financial statement carrying amounts and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the year in which the temporary differences are expected to be reversed. Changes to enacted tax rates would result in either increases or decreases in the provision for income taxes in the period of changes. The Company evaluates the realizability of deferred tax assets and recognizes a valuation allowance when it is more likely than not that all, or a portion of, deferred tax assets will not be realized.
	The realization of deferred tax assets is primarily dependent on future earnings. Any reduction in estimated forecasted results may require that we record valuation allowances against deferred tax assets. Once a valuation allowance has been established, it will be maintained until there is sufficient positive evidence to conclude that it is more likely than not that the deferred tax assets will be realized. A pattern of sustained profitability will generally be considered as sufficient positive evidence to reverse a valuation allowance. If the allowance is reversed in a future period, the income tax provision will be correspondingly reduced. Accordingly, the increase and decrease of valuation allowances could have a significant negative or positive impact on future earnings. See Note 10 to the consolidated financial statements for further information.
	Changes in tax laws and rates may affect recorded deferred tax assets and liabilities and our effective tax rate in the future. The American Taxpayer Relief Act of 2012 (the “Act”) was signed into law on January 2, 2013. Because a change in tax law is accounted for in the period of enactment, certain provisions of the Act benefiting the Company’s 2012 U.S. federal taxes, including the Subpart F controlled foreign corporation look-through exception were not recognized in the Company’s 2012 financial results and instead were reflected in the Company’s 2013 financial results.
Earnings Per Share (EPS)	Earnings per Share (“EPS”) — Basic EPS is computed by dividing the net income applicable to common stockholders for the period by the weighted average number of shares of common stock outstanding during the same period. The Company’s Series A-1 Preferred, Series A-2 Preferred, and Series A-3 Preferred Stock, that had been outstanding and convertible into common stock until February 13, 2012 (the date of the Company’s initial public offering), and our puttable common stock were considered participating securities since these securities had non-forfeitable rights to dividends or dividend equivalents during the contractual period and thus required the two-class method of computing EPS. When calculating diluted EPS, the numerator is computed by adding back the undistributed earnings allocated to the participating securities in arriving at the basic EPS and then reallocating such undistributed earnings among our common stock, participating securities and the potential common shares that result from the assumed exercise of all dilutive options. The denominator is increased to include the number of additional common shares that would have been outstanding had the options been issued.
Stock-based Compensation	Stock-Based Compensation — Equity-based compensation cost relating to the issuance of share-based awards to employees is based on the fair value of the award at the date of grant, which is expensed ratably over the requisite service period, net of estimated forfeitures. The forfeiture assumption is ultimately adjusted to the actual forfeiture rate. Therefore, changes in the forfeiture assumptions may affect the timing of the total amount of expense recognized over the vesting period. The service period is the period over which the employee performs the related services, which is normally the same as the vesting period. Equity-based awards that do not require future service are expensed immediately. Equity-based awards that do not meet criteria for equity classification are recorded in liabilities and adjusted to fair value at the end of each reporting period. Distributions associated with liability-classified awards not expected to vest are accounted for as compensation expense in the consolidated statements of income and comprehensive income.
Off-Balance Sheet Financial Instruments	Off-Balance Sheet Financial Instruments — Include credit instruments, such as standby letters of credit and guarantees issued under customer contracts. The face amount for these items represents the exposure to loss, before considering available collateral or the borrower’s ability to repay. Such financial instruments are recorded when they are funded. Loss contingencies arising from off-balance sheet credit exposures are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. The Company does not believe there are such matters that will have a material effect on the consolidated financial statements.
Foreign Currency Transaction	Foreign Currency Translation — Assets and liabilities of consolidated foreign subsidiaries, whose functional currency is the local currency, are translated to U.S. dollars at period end exchange rates. Revenues and expenses are translated to U.S. dollars at daily exchange rates. The adjustment resulting from translating the financial statements of such foreign subsidiaries to U.S. dollars is reflected as a cumulative translation adjustment and reported as a component of accumulated other comprehensive income.
	The Company reports the effect of exchange rate changes on cash balances held in foreign currencies as a separate item in the reconciliation of the changes in cash and cash equivalents during the period. Transaction gains and losses are included in the period in which they occur.
Risks and Uncertainties	Risks and Uncertainties — Principally all of the Company’s IT delivery centers and a majority of its employees are located in Central and Eastern Europe and the APAC region. As a result, the Company may be subject to certain inherent risks associated with international operations, including the application and imposition of protective legislation and regulations relating to import and export; difficulties in enforcing intellectual property and contractual rights; complying with a wide variety of foreign laws; potentially adverse tax consequences; tariffs, quotas and other trade protection methods; and overall foreign policy and variability of foreign economic conditions.
	Concentration of Credit — The Company maintains cash and cash equivalents and short-term investments with financial institutions. The Company determined that the Company's credit policies reflect normal industry terms and business risk and there is no expectation of non-performance by the counterparties. As of December 31, 2014, $59.3 million of total cash was held in CIS countries, with $34.2 million of that in Belarus. Banking and other financial systems in the CIS region are less developed and regulated than in some more developed markets, and legislation relating to banks and bank accounts is subject to varying interpretations and inconsistent application. Banks in the CIS region generally do not meet the banking standards of more developed markets and bank deposits made by corporate entities in the CIS region are not insured. The CIS banking sector remains subject to periodic instability and the transparency of the banking sector lags behind international standards. A banking crisis, bankruptcy or insolvency of banks that process or hold our funds, particularly in Belarus, may result in the loss of our deposits or adversely affect our ability to complete banking transactions in the CIS region, which could materially adversely affect our business and financial condition.
	As of December 31, 2014, unbilled trade receivables from one customer, UBS AG, individually exceeded 10% and accounted for 16.5% of our total unbilled trade receivables as of that date. There were no customers individually exceeding 10% of our billed trade receivables as of December 31, 2014.
	During the years ended December 31, 2014, 2013 and 2012, revenues from our top five customers were $239,396, $169,987 and $134,484, respectively, representing 32.8%, 30.6% and 31.0%, respectively, of total revenues in the corresponding periods. Revenues from our top ten customers were $320,126, $234,955 and $192,426 in 2014, 2013 and 2012, respectively, representing 43.9%, 42.3% and 44.4%, respectively, of total revenues in corresponding periods.
	During the year ended December 31, 2014, the Company had one customer, UBS AG, with revenues of $97.6 million, which accounted for more than 10% of total revenues. No customer accounted for over 10% of total revenues in 2013 and 2012.
	During the years ended December 31, 2014, 2013 and 2012 the Company incurred subcontractor costs of $1,885, $2,078 and $3,535, respectively, to a vendor for staffing, consulting, training, recruiting and other logistical / support services provided for the Company’s delivery and development operations in Eastern Europe. Such costs are included in cost of revenues and sales, general and administrative expenses, as appropriate, in the accompanying consolidated statements of income and comprehensive income.
	Foreign currency risk — The Company generates revenues in various global markets based on client contracts obtained in non-U.S. dollar currencies, principally, Euros, British pounds, Canadian dollars, and Russian rubles. The Company incurs expenditures in non-U.S. dollar currencies, principally in Hungarian forints, Euros, Russian rubles, and Hong Kong dollars and China yuan renminbi (“CNY”) associated with the IT delivery centers located in CEE and APAC regions. The Company is exposed to fluctuations in foreign currency exchange rates primarily on accounts receivable and unbilled revenues from sales in these foreign currencies, and cash flows for expenditures in foreign currencies. The Company does not use derivative financial instruments to hedge the risk of foreign exchange volatility.
	Interest rate risk — The Company’s exposure to market risk is influenced primarily by changes in interest rates on interest payments received on cash and cash equivalent deposits and paid on any outstanding balance on the Company's revolving line of credit, which is subject to a variety of rates depending on the type and timing of funds borrowed (see Note 12). The Company does not use derivative financial instruments to hedge the risk of interest rate volatility.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In November 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-17, Business Combinations (Topic 805): Pushdown Accounting. The update provides an acquired entity with an option to apply pushdown accounting in its separate financial statements upon occurrence of an event in which an acquirer obtains control of the acquired entity. An acquired entity may also elect the option to apply pushdown accounting in the reporting period in which the change-in-control event occurs. However, if the financial statements for the period in which the most recent change-in-control event occurred already have been issued or made available to be issued, the application of this guidance would be a change in accounting principle. The amendment is effective on November 18, 2014. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements.
	In November 2014, the FASB issued ASU 2014-16, Derivatives and Hedging (Topic 815): Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share Is More Akin to Debt or to Equity. The update aims to eliminate the use of different methods in practice and thereby reduce existing diversity under GAAP in the accounting for hybrid financial instruments issued in the form of a share. The amendments are effective for annual period and interim periods within those annual periods, beginning after December 15, 2015 with early adoption permitted. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements as the Company currently does not engage in derivatives and hedging.
	In August 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements-Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. The amendments in this update provide guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. These amendments aim to reduce diversity in the timing and content of footnote disclosures. The amendments in this update are effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter, with early adoption permitted. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements.
	In June 2014, the FASB issued ASU 2014-12, which requires that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. A reporting entity should apply existing guidance in Topic 718, Compensation - Stock Compensation, as it relates to awards with performance conditions that affect vesting to account for such awards. The standard is effective for annual periods and interim periods within those annual periods beginning after December 15, 2015 with early adoption permitted. Entities may apply the amendments in this ASU either: (a) prospectively to all awards granted or modified after the effective date or (b) retrospectively to all awards with performance targets that are outstanding as of the beginning of the earliest annual period presented in the financial statements and to all new or modified awards thereafter. The implementation of this standard is not expected to have a material effect on the Company’s consolidated financial statements.
	In May 2014, the FASB issued ASU 2014-09, which impacts virtually all aspects of an entity’s revenue recognition. The ASU introduces a new five-step revenue recognition model in which an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. This ASU also requires disclosures sufficient to enable users to understand the nature, amount, timing, and uncertainty of revenue and cash flows arising from contracts with customers, including qualitative and quantitative disclosures about contracts with customers, significant judgments and changes in judgments, and assets recognized from the costs to obtain or fulfill a contract. This standard is effective for fiscal periods beginning after December 15, 2016, including interim periods within that reporting period. The Company is currently evaluating the new guidance to determine the impact it will have on its consolidated financial statements.
	In April 2014, the FASB issued ASU 2014-08, Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, which changes the criteria for determining which disposals can be presented as discontinued operations and modifies the related disclosure requirements. To qualify as a discontinued operation the standard requires a disposal to represent a strategic shift that has, or will have, a major effect on an entity's operations and financial results. The standard also expands the disclosures for discontinued operations and requires new disclosures related to individually material dispositions that do not qualify as discontinued operations. The standard is effective prospectively for fiscal periods beginning after December 15, 2014, including interim periods within that reporting period, with early adoption permitted. The implementation of this standard is not expected to have a material impact on the Company’s consolidated financial statements, but will impact the reporting of any future dispositions.
	In July 2013, the FASB issued ASU 2013-11, Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. ASU 2013-11 is a new accounting standard on the financial statement presentation of unrecognized tax benefits. The new standard provides that a liability related to an unrecognized tax benefit would be presented as a reduction of a deferred tax asset for a net operating loss carryforward, a similar tax loss or a tax credit carryforward if such settlement is required or expected in the event the uncertain tax position is disallowed. The new standard became effective for the periods commencing January 1, 2014, and it should be applied prospectively to unrecognized tax benefits that exist at the effective date with retrospective application permitted. The Company adopted the ASU effective January 1, 2014. The adoption of this standard did not have any effect on the Company’s consolidated financial statements.

NATURE_OF_BUSINESS_AND_SIGNIFI2

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Allowance for Credit Losses on Financing Receivables	The table below summarizes movements in qualifying accounts for the years ended December 31, 2014, 2013 and 2012:
		Balance at		Charged to Costs		Deductions/			Balance at End of Year
		Beginning of		and Expenses		Other
		Period
	Allowance for Doubtful Accounts (Billed and Unbilled):
	Fiscal Year 2012	$	2,250	$	1,244	$	(1,291	)	$	2,203
	Fiscal Year 2013	2,203		619		(1,022		)	1,800
	Fiscal Year 2014	1,800		1,325		(944		)	2,181

ACQUISITIONS_Tables

ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2014
Business Combinations [Abstract]
Summary of Acquisitions in Exchange for Common Stock and/or Cash	The table below discloses respective details of each acquisition.
	Name of Acquisition		Effective Date of Acquisition	Common Shares						Fair Value of Common							Cash, Net of Working Capital and Other Adjustments								Recorded Earnout						Total Recorded Purchase Price		Maximum Potential Earnout Payable
										Shares															Payable
				Issued			Deferred			Issued			Deferred				Paid				Deferred				Cash			Stock
				(in shares)						(in thousands)
	Netsoft		5-Mar-14	—			—			$	—		$	—			$	2,373			$	1,022			$	1,825		$	—		$	5,220	$	1,825
	Jointech		30-Apr-14	—			89,552			—			2,788				10,000				4,000				15,000			5,000			36,788		20,000
	GGA (1)		6-Jun-14	—			—			—			—				14,892				—				11,400			—			26,292
	Great Fridays		31-Oct-14	—			—			—			—				10,854				—				1,173			—			12,027		1,173
				—			89,552			$	—		$	2,788			$	38,119			$	5,022			$	29,398		$	5,000		$	80,327
	-1	The amount of the maximum potential earnout payable to GGA, if any, is not limited based on the terms of the purchase agreement.
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following is a summary of the preliminary estimated fair values of the net assets acquired at the date of each respective acquisition during the year ended December 31, 2014 as originally reported in the quarterly condensed consolidated financial statements and at December 31, 2014:
		Netsoft							Jointech							GGA								Great Fridays			Total
		At Originally Reported			At December 31, 2014				As Originally Reported			At December 31, 2014				As Originally Reported				At December 31, 2014				At December 31, 2014			As Originally Reported			At December 31, 2014
	Cash and cash equivalents	$	—		$	—			$	871		$	871			$	—			$	—			$	259		$	1,130		$	1,130
	Trade receivables and other current assets	788			788				784			784				5,157				5,471				1,825			8,554			8,868
	Property and equipment and other long-term assets	52			52				338			338				444				444				262			1,096			1,096
	Deferred tax asset	351			—				—			—				4,463				—				—			4,814			—
	Acquired intangible assets	1,700			1,700				25,744			22,485				10,959				10,959				5,747			44,150			40,891
	Goodwill	2,776			2,749				11,033			17,404				6,496				12,115				6,947			27,252			39,215
	Total assets acquired	5,667			5,289				38,770			41,882				27,519				28,989				15,040			86,996			91,200
	Accounts payable and accrued expenses	69			69				728			728				2,593				2,593				872			4,262			4,262
	Deferred revenue	—			—				—			—				—				104				317			317			421
	Due to employees	—			—				1,254			1,254				—				—				624			1,878			1,878
	Deferred tax liability	—			—				—			3,112				—				—				1,200			1,200			4,312
	Total liabilities assumed	69			69				1,982			5,094				2,593				2,697				3,013			7,657			10,873
	Net assets acquired	$	5,598		$	5,220			$	36,788		$	36,788			$	24,926			$	26,292			$	12,027		$	79,339		$	80,327
	The above estimated fair values of the assets acquired and liabilities assumed are provisional and based on the information that was available as of the acquisition date and updated for any changes as of December 31, 2014. During the year ended December 31, 2014, the following updates were made to the initially reported balances with some of the adjustments being reported in the third quarter between goodwill and deferred tax accounts.
	For Netsoft, the deferred tax asset and goodwill were adjusted and decreased the net assets acquired by $378. For Jointech, intangible assets were adjusted to reflect the results of a preliminary valuation report obtained and a deferred tax liability was established, both increasing goodwill with no change to the net assets acquired. For GGA, additional accounts receivable and deferred revenue were recognized, deferred tax assets were netted with recognized deferred tax liabilities, and the final working capital adjustment was completed, which in aggregate increased the net assets acquired by $1,366.
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	The following table presents the estimated fair values and useful lives of intangible assets acquired during the year ended December 31, 2014:
		Netsoft						Jointech					GGA							Great Fridays
		Weighted Average		Amount				Weighted Average		Amount			Weighted Average			Amount				Weighted Average			Amount
		Useful Life						Useful Life					Useful Life							Useful Life
		(in years)						(in years)					(in years)							(in years)
	Customer relationships	10		$	1,700			10		$	22,173		10			$	10,959			10			$	5,747
	Trade names	—		—				2		312			—			—				—			—
	Total			$	1,700					$	22,485					$	10,959						$	5,747
Summary of Revenues, Net Income/(Losses) And Acquisition-Related Costs	The following is a summary of revenues, net income and acquisition-related costs included in the consolidated statements of income and comprehensive income for the year ended December 31, 2014:
		For the Year Ended December 31, 2014
		Netsoft					Jointech					GGA						Great Fridays						Total
	Revenues	$	5,068				$	13,060				$	19,809					$	1,821					$	39,758
	Net Income	806		1			(3,090		)	2		822			3			(72		)	4			(1,534		)
	Acquisition-related costs	$	75				$	361				$	325					$	24					$	785
	-1	Included in net income is $252 of stock-based compensation expense related to the Netsoft Employment Shares for the year ended December 31, 2014.
	-2	Included in net income is $1,738 of stock-based compensation expense related to the Jointech Employment Shares for the year ended December 31, 2014.
	-3	Included in net income is $4,322 of stock-based compensation expense related to the GGA Employment Shares for the year ended December 31, 2014.
	-4	Included in net income is $239 of stock-based compensation expense related to the Great Fridays Employment Shares for the year ended December 31, 2014.

GOODWILL_AND_INTANGIBLE_ASSETS1

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill By Reportable Segment	Goodwill by reportable segment was as follows:
		North America				Europe				Russia				Total
	Balance as of January 1, 2013	$	16,643			$	2,864			$	3,191			$	22,698
	Net effect of foreign currency exchange rate changes	(205		)		—				(225		)		(430		)
	Balance as of December 31, 2013	16,438				2,864				2,966				22,268
	Acquisition of Netsoft (Note 2)	2,749				—				—				2,749
	Acquisition of Jointech (Note 2)	—				17,404				—				17,404
	Acquisition of GGA (Note 2)	12,115				—				—				12,115
	Acquisition of Great Fridays (Note 2)	—				6,947				—				6,947
	Goodwill written-off	—				—				(2,241		)		(2,241		)
	Net effect of foreign currency exchange rate changes	(224		)		(876		)		(725		)		(1,825		)
	Balance as of December 31, 2014	$	31,078			$	26,339			$	—			$	57,417
Components of Intangible Assets
		2014
		Weighted average life at acquisition (in years)		Gross carrying amount				Accumulated amortization				Net
												carrying amount
	Client relationships	10		$	48,482			$	(4,664	)		$	43,818
	Trade name	5		6,372				(2,894		)		3,478
	Non-competition agreements	5		813				(420		)		393
	Total			$	55,667			$	(7,978	)		$	47,689
		2013
		Weighted average life at acquisition (in years)		Gross carrying amount				Accumulated amortization				Net
												carrying amount
	Client relationships	9		$	13,432			$	(4,885	)		$	8,547
	Trade name	5		6,232				(1,643		)		4,589
	Non-competition agreements	5		848				(250		)		598
	Total			$	20,512			$	(6,778	)		$	13,734
		2012
		Weighted average life at acquisition (in years)		Gross carrying amount				Accumulated amortization				Net
												carrying amount
	Client relationships	9		$	13,724			$	(3,640	)		$	10,084
	Trade name	5		6,372				(439		)		5,933
	Non-competition agreements	5		881				(64		)		817
	Total			$	20,977			$	(4,143	)		$	16,834
Finite-lived Intangible Assets Amortization Expense [Table Text Block]	All of the intangible assets have finite lives and as such are subject to amortization. Recognized amortization expense for the years ended December 31 is presented in the table below:
			For the Years Ended December 31,
			2014				2013				2012
	Client relationships		$	3,843			$	1,373			$	627
	Trade name		1,319				1,222				333
	Non-competition agreements		187				190				64
	Total		$	5,349			$	2,785			$	1,024
Estimated Amortization Expenses	Estimated amortization expenses of the Company’s existing intangible assets for the next five years ending December 31, were as follows:
			Amount
	2015		$	6,520
	2016		6,383
	2017		5,957
	2018		5,032
	2019		4,748
	Thereafter		19,049
	Total		$	47,689

PREPAID_AND_OTHER_CURRENT_ASSE1

PREPAID AND OTHER CURRENT ASSETS (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid and Other Current Assets	Prepaid and other current assets consisted of the following:
		December 31,		December 31,
		2014		2013
	Taxes receivable	$	3,966	$	7,295
	Prepaid expenses	3,703		3,399
	Security deposits under operating leases	476		1,005
	Prepaid equipment	185		986
	Unamortized software licenses and subscriptions	454		981
	Due from employees	96		218
	Other	409		471
	Total	$	9,289	$	14,355

EMPLOYEE_LOANS_AND_ALLOWANCE_F1

EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES (Tables)	12 Months Ended
	Dec. 31, 2014
Loans and Leases Receivable, Related Parties Disclosure [Abstract]
Categories of Employee Loans Included in Loans Portfolio	At December 31, 2014 and December 31, 2013, categories of employee loans included in the loan portfolio were as follows:
		December 31,		December 31,
		2014		2013
	Housing loans	$	5,848	$	5,896
	Relocation and other loans	667		494
	Total employee loans	6,515		6,390
	Less:
	Allowance for loan losses	—		—
	Total loans, net of allowance for loan losses	$	6,515	$	6,390

RESTRICTED_CASH_AND_TIME_DEPOS1

RESTRICTED CASH AND TIME DEPOSITS (Tables)	12 Months Ended
	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Schedule of Restricted Cash and Cash Equivalents	Restricted cash and time deposits consisted of the following:
		December 31,		December 31,
		2014		2013
	Time deposits	$	—	$	1,188
	Short-term security deposits under customer contracts	—		298
	Long-term deposits under employee loan programs	156		225
	Long-term deposits under operating leases	—		—
	Total	$	156	$	1,711

PROPERTY_AND_EQUIPMENT_NET_Tab

PROPERTY AND EQUIPMENT - NET (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment
	7	PROPERTY AND EQUIPMENT — NET
	Property and equipme

ACCRUED_EXPENSES_AND_OTHER_LIA1

ACCRUED EXPENSES AND OTHER LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued expenses consisted of the following:
		December 31,		December 31,
		2014		2013
	Compensation	$	22,766	$	13,674
	Acquisition related deferred consideration	1,022		—
	Subcontractor costs	2,815		2,933
	Professional fees	1,162		947
	Facilities costs	757		334
	Other	3,681		2,287
	Total	$	32,203	$	20,175

TAXES_PAYABLE_TAXES_PAYABLE_Ta

TAXES PAYABLE TAXES PAYABLE (Tables)	12 Months Ended
	Dec. 31, 2014
Taxes Payable, Current [Abstract]
TaxesPayable	Current taxes payable consisted of the following:
		December 31,		December 31,
		2014		2013
	Corporate profit tax	$	7,982	$	3,717
	Value added taxes	6,279		5,975
	Payroll, social security, and other taxes	10,443		4,479
	Total	$	24,704	$	14,171

INCOME_TAXES_Tables

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income before provision of income taxes	Income before provision for income taxes shown below was based on the geographic location to which such income was attributed as follows:
		For the Years Ended December 31,
		2014			2013			2012
	Income before income tax expense:
	Domestic	$	(7,229	)	$	7,001		$	9,291
	Foreign	94,182			69,769			56,572
	Total	$	86,953		$	76,770		$	65,863
Components of income tax expense
		For the Years Ended December 31,
		2014			2013			2012
	Income tax expense (benefit) consists of:
	Current
	Federal	$	7,741		$	6,150		$	6,881
	State	338			310			319
	Foreign	12,504			8,275			7,969
	Deferred
	Federal	(3,979		)	(668		)	(625		)
	State	(43		)	14			24
	Foreign	751			695			(3,189		)
	Total	$	17,312		$	14,776		$	11,379
Components of deferred tax assets and liabilities	The components of the Company’s deferred tax assets and liabilities were as follows:
		December 31,			December 31,
		2014			2013
	Deferred tax assets:
	Fixed assets	$	181		$	732
	Intangible assets	3,789			4,532
	Accrued expenses	1,282			3,488
	Net operating loss carryforward	844			—
	Deferred revenue	4,328			2,050
	Stock-based compensation	6,994			407
	Valuation allowance	(149		)	—
	Restricted stock options	2			1,336
	Other assets	30			680
	Deferred tax assets	17,301			13,225
	Deferred tax liabilities:
	Fixed assets	800			804
	Accrued revenue and expenses	635			846
	Deferred inter-company gain	405			405
	Equity compensation	7,013			1,593
	Other liabilities	24			254
	Deferred tax liability	8,877			3,902
	Net deferred tax asset	$	8,424		$	9,323
Reconciliation of effective income tax	The provision for income taxes differs from the amount of income tax determined by applying the applicable US statutory federal income tax rate to pretax income as follows:
		For the Years Ended December 31,
		2014			2013			2012
	Statutory federal tax	$	29,564		$	26,102		$	22,393
	Increase/ (decrease) in taxes resulting from:
	State taxes, net of federal benefit	311			368			280
	Provision adjustment for current year uncertain tax position	(1,220		)	—			—
	Effect of permanent differences	8,589			2,524			2,177
	Stock-based compensation	3,782			1,948			1,165
	Rate differential between U.S. and foreign	(24,772		)	(17,279		)	(14,472		)
	Change in foreign tax rate	754			(59		)	148
	Change in valuation allowance	149			489			(489		)
	Other	155			683			177
	Provision for income taxes	$	17,312		$	14,776		$	11,379
Unrecognized tax benefits	The beginning to ending reconciliation of the gross unrecognized tax benefits were as follows:
		For the Years Ended December 31,
		2014			2013			2012
	Gross Balance at January 1	$	1,271		$	1,271		$	1,271
	Increases in tax positions in current year	—			—			—
	Increases in tax positions in prior year	—			—			—
	Decreases due to settlement	(1,071		)	—			—
	Balance at December 31	$	200		$	1,271		$	1,271

COMMON_AND_PREFERRED_STOCK_Tab

COMMON AND PREFERRED STOCK (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Conversion of Convertible Preferred Stock	Upon the closing of the initial public offering, all outstanding Series-A1 and Series-A2 convertible redeemable preferred stock, and Series A3 convertible preferred stock were converted into a total of 21,840,128 shares of common stock, as shown in the table below.
		Conversion Shares
	Series A-1 Convertible Redeemable Preferred Stock	16,439,480
	Series A-2 Convertible Redeemable Preferred Stock	3,078,432
	Series A-3 Convertible Preferred Stock	2,322,216
	Total	21,840,128

STOCKBASED_COMPENSATION_Tables

STOCK-BASED COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Costs Related to Stock Compensation Plans	The following costs related to the Company’s stock compensation plans were included in the consolidated statements of income and comprehensive income:
			For the Years Ended December 31,
			2014				2013				2012
	Cost of revenues		$	8,648			$	4,823			$	2,809
	Selling, general and administrative expenses		15,972				8,327				4,017
	Total		$	24,620			$	13,150			$	6,826
Stock Option Activity	Stock option activity under the Company’s plans is set forth below:
		Number of			Weighted Average				Aggregate
		Options			Exercise Price				Intrinsic Value
	Options outstanding at January 1, 2012	6,595,136			$	4.65			$	48,447
	Options granted	1,443,810			16.8				1,877
	Options exercised	(1,552,742	)		3.53				(22,623		)
	Options forfeited/cancelled	(189,495	)		11.35				(1,279		)
	Options outstanding at December 31, 2012	6,296,709			$	7.51			$	66,682
	Options granted	1,987,952			23.6				22,543
	Options exercised	(2,156,898	)		4.31				(66,066		)
	Options forfeited/cancelled	(304,227	)		11.5				(7,131		)
	Options outstanding at December 31, 2013	5,823,536			$	13.99			$	122,003
	Options granted	2,400,500			32.51				36,584
	Options exercised	(1,171,097	)		9.05				(45,321		)
	Options forfeited/cancelled	(214,193	)		25.33				(4,802		)
	Options outstanding at December 31, 2014	6,838,746			$	20.98			$	183,073
	Options vested and exercisable at December 31, 2014	2,406,016			$	9.83			$	91,236
	Options expected to vest	4,074,226			$	26.82			$	85,274
Service-based Awards Activity	Summarized activity related to the Company’s service-based awards for the years ended December 31, 2014, 2013 and 2012 was as follows:
		Number of			Weighted Average Grant Date
		Shares			Fair Value Per Share
	Unvested service-based awards outstanding at January 1, 2012	—			$	—
	Awards granted	757,272			17.15
	Awards vested	(97,400	)		12
	Unvested service-based awards outstanding at December 31, 2012	659,872			$	17.92
	Awards granted	15,524			23.69
	Awards vested	(330,468	)		17.33
	Unvested service-based awards outstanding at December 31, 2013	344,928			$	18.74
	Awards granted	523,220			40.41
	Awards vested	(217,668	)		17.84
	Awards forfeited/cancelled	(17,038	)		21.14
	Unvested service-based awards outstanding at December 31, 2014	633,442			$	36.88
Performance-based Awards Activity	Summarized activity related to the Company’s performance-based awards for the years ended December 31, 2014, was as follows:
		Number of Shares			Weighted Average Grant Date Fair Value Per Share
	Unvested performance-based awards outstanding at December 31, 2013	—			$	—
	Awards granted	387,058			38.18
	Awards vested	—			—
	Awards forfeited/cancelled	(2,550	)		36.57
	Changes in the number of awards expected to be delivered	(12,998	)		5.47
	Unvested performance-based awards outstanding at December 31, 2014	371,510			$	39.34

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share of common stock as follows:
		For the Years Ended December 31,
		2014		2013		2012
	Numerator for common earnings per share:
	Net income	$	69,641	$	61,994	$	54,484
	Net income allocated to participating securities	—		—		(3,341		)
	Numerator for basic earnings per share	69,641		61,994		51,143
	Effect on income available from reallocation of options	—		—		261
	Numerator for diluted earnings per share	$	69,641	$	61,994	$	51,404
	Denominator for basic earnings per share:
	Weighted average common shares outstanding	47,189		45,754		40,190
	Effect of dilutive securities:
	Stock options, RSUs and performance-based awards	2,545		2,604		3,631
	Denominator for diluted earnings per share	49,734		48,358		43,821
	Net income per share:
	Basic	$	1.48	$	1.35	$	1.27
	Diluted	$	1.4	$	1.28	$	1.17

COMMITMENTS_AND_CONTINGENCIES_

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Future minimum rental payments under operating leases	Future minimum rental payments under operating leases that have initial or remaining lease terms in excess of one year as of December 31, 2014 were as follows:
	Year Ending December 31,	Operating Leases
	2015	$	16,718
	2016	10,482
	2017	7,668
	2018	4,993
	2019	3,589
	Thereafter	952
	Total minimum lease payments	$	44,402

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value on Recurring Basis	The following table represents the Company’s fair value hierarchy for its financial assets as of December 31, 2014 and 2013.
			As of December 2014
			Balance			Level 1		Level 2		Level 3
	Cash and cash equivalents		$	220,534		$	220,534	$	—	$	—
	Time deposits and restricted cash		156			—		156		—
	Employee loans		6,515			—		—		6,515
	Total assets measured at fair value on recurring basis		$	227,205		$	220,534	$	156	$	6,515
			As of December 2013
			Balance			Level 1		Level 2		Level 3
	Cash and cash equivalents		$	169,207		$	169,207	$	—	$	—
	Time deposits and restricted cash		1,711			—		1,711		—
	Employee loans		6,390			—		—		6,390
	Total assets measured at fair value on recurring basis		$	177,308		$	169,207	$	1,711	$	6,390
Liabilities Measured at Fair Value on Recurring Basis	The following tables show the fair values of the Company’s financial liabilities measured at fair value on a recurring basis:
		As of December 31, 2014
		Balance			Level 3
	Contingent consideration	$	37,400		$	37,400
	Performance-based equity awards	3,223			3,223
	Total liabilities measured at fair value on a recurring basis	$	40,623		$	40,623
Reconciliation of Liabilities Measured on Recurring Basis, Unobservable Input	A reconciliation of the beginning and ending balances of acquisition-related contractual contingent liabilities using significant unobservable inputs (Level 3) for the year ended December 31, 2014 , was as follows:
		Amount
	Contractual contingent liabilities at January 1, 2014	$	—
	Acquisition date fair value of contractual contingent liabilities — Netsoft	1,825
	Acquisition date fair value of contractual contingent liabilities — Jointech	20,000
	Acquisition date fair value of contractual contingent liabilities — GGA	11,400
	Acquisition date fair value of contractual contingent liabilities — Great Fridays	1,173
	Liability-classified stock-based awards	3,088
	Changes in fair value of contractual contingent liabilities included in earnings	2,059
	Changes in fair value of contractual contingent liabilities recorded against goodwill	1,366
	Effect of net foreign currency exchange rate changes	(288		)
	Contractual contingent liabilities at December 31, 2014	$	40,623

OPERATING_SEGMENTS_Tables

OPERATING SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Revenues from External Customers and Segment Operating Profit Before Unallocated Expenses	Revenues from external customers and segment operating profit, before unallocated expenses, for the North America, Europe, Russia and Other reportable segments were as follows:
			For the years ended December 31,
			2014				2013			2012
	Total segment revenues:
	North America		$	374,509			$	284,636		$	197,271
	Europe		299,279				204,150			168,913
	Russia		50,663				55,764			50,552
	Other		5,552				10,493			16,986
	Total segment revenues		$	730,003			$	555,043		$	433,722
	Segment operating profit:
	North America		$	90,616			$	66,814		$	38,671
	Europe		50,189				34,573			32,750
	Russia		7,034				7,077			9,049
	Other		(3,220		)		844			6,985
	Total segment operating profit		$	144,619			$	109,308		$	87,455
Reconciliation of Segment Revenues and Operating Profit to Consolidated Income Before Provision for Income Taxes	Reconciliation of segment revenues and operating profit to consolidated income before provision for income taxes is presented below:
			For the Years Ended December 31,
			2014				2013			2012
	Total segment revenues		$	730,003			$	555,043		$	433,722
	Unallocated revenue		24				74			77
	Revenues		$	730,027			$	555,117		$	433,799
	Total segment operating profit:		$	144,619			$	109,308		$	87,455
	Unallocated amounts:
	Other revenues		24				74			77
	Stock-based compensation expense		(24,620		)		(13,150		)	(6,826		)
	Non-corporate taxes		(6,882		)		(3,201		)	(2,346		)
	Professional fees		(5,312		)		(3,651		)	(2,850		)
	Depreciation and amortization		(7,988		)		(2,829		)	(1,100		)
	Bank charges		(1,049		)		(1,194		)	(1,136		)
	Asset impairment		(5,983		)		—			—
	Stock charge		—				—			(640		)
	Provision for bad debts		—				(36		)	—
	Other corporate expenses		(6,626		)		(8,828		)	(6,628		)
	Income from operations		86,183				76,493			66,006
	Interest and other income, net		4,769				3,077			1,941
	Change in fair value of contingent consideration		(1,924		)		—			—
	Foreign exchange loss		(2,075		)		(2,800		)	(2,084		)
	Income before provision for income taxes		$	86,953			$	76,770		$	65,863
Geographical Information of Long-Lived Assets Based on Physical Location	Long-lived assets include property and equipment, net of accumulated depreciation and amortization, and management has determined that it is not practical to allocate these assets by segment since such assets are used interchangeably among the segments. Geographical information about the Company’s long-lived assets based on physical location of the assets was as follows:
		December 31,				December 31,
		2014				2013
	Belarus	$	41,652			$	38,697
	Ukraine	4,392				5,525
	Hungary	2,773				2,644
	Russia	2,196				3,414
	United States	2,001				2,217
	Other	2,120				818
	Total	$	55,134			$	53,315
Revenues by Client Location	Information about the Company’s revenues by client location is as follows:
			For the Years Ended December 31,
			2014				2013			2012
	United States		$	318,304			$	247,979		$	197,593
	United Kingdom		141,366				108,892			98,346
	Switzerland		87,111				51,941			30,120
	Russia		48,945				53,328			47,507
	Canada		49,193				33,759			9,256
	Germany		25,740				20,261			16,391
	China		13,445				—			—
	Netherlands		8,838				7,719			3,127
	Sweden		7,892				5,742			4,913
	Kazakhstan		5,238				9,886			11,352
	Other locations		15,545				7,984			8,777
	Reimbursable expenses and other revenues		8,410				7,626			6,417
	Revenues		$	730,027			$	555,117		$	433,799
Revenues by Service Offering	Information about the Company’s revenues by service offering is as follows:
			For the Years Ended December 31,
			2014				2013			2012
	Software development		$	504,590			$	374,426		$	290,139
	Application testing services		140,363				109,222			85,849
	Application maintenance and support		58,840				45,971			36,056
	Infrastructure services		14,198				14,433			12,424
	Licensing		3,626				3,439			2,914
	Reimbursable expenses and other revenues		8,410				7,626			6,417
	Revenues		$	730,027			$	555,117		$	433,799

QUARTERLY_FINANCIAL_DATA_Table

QUARTERLY FINANCIAL DATA (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Summarized quarterly results for the two years ended December 31, 2014 and 2013 were as follows:
			Three Months Ended
	2014		March 31			June 30			September 30			December 31			Full Year
	Revenues		$	160,384		$	174,695		$	192,764		$	202,184		$	730,027
	Operating expenses:
	Cost of revenues (exclusive of depreciation and amortization)		102,454			110,102			122,509			121,465			456,530
	Selling, general and administrative expenses		32,359			38,671			42,875			49,761			163,666
	Depreciation and amortization expense		3,689			5,451			5,510			2,833			17,483
	Goodwill impairment loss		—			—			—			2,241			2,241
	Other operating (income)/ expenses, net		25			1,995			35			1,869			3,924
	Income from operations		21,857			18,476			21,835			24,015			86,183
	Interest and other income, net		976			1,164			1,261			1,368			4,769
	Change in fair value of contingent consideration		—			—			—			(1,924		)	(1,924		)
	Foreign exchange loss		(1,241		)	(1,239		)	(718		)	1,123			(2,075		)
	Income before provision for income taxes		21,592			18,401			22,378			24,582			86,953
	Provision for income taxes		4,228			3,587			3,338			6,159			17,312
	Net income		$	17,364		$	14,814		$	19,040		$	18,423		$	69,641
	Comprehensive income		$	13,787		$	17,708		$	10,780		$	7,115		$	49,390
	Basic net income per share(1)		$	0.37		$	0.31		$	0.4		$	0.39		$	1.48
	Diluted net income per share(1)		$	0.35		$	0.3		$	0.38		$	0.37		$	1.4
	-1	Earnings per share amounts for each quarter may not necessarily total to the yearly earnings per share due to the weighting of shares outstanding on a quarterly and year to date basis.
			Three Months Ended
	2013		March 31			June 30			September 30			December 31			Full Year
	Revenues		$	124,198		$	133,184		$	140,150		$	157,585		$	555,117
	Operating expenses:
	Cost of revenues (exclusive of depreciation and amortization)		77,937			83,547			88,539			97,627			347,650
	Selling, general and administrative expenses		27,083			28,541			27,893			32,980			116,497
	Depreciation and amortization expense		3,617			3,854			3,906			3,743			15,120
	Goodwill impairment loss		—			—			—			—			—
	Other operating (income)/ expenses, net		25			(293		)	(418		)	43			(643		)
	Income from operations		15,536			17,535			20,230			23,192			76,493
	Interest and other income, net		630			769			846			832			3,077
	Change in fair value of contingent consideration		—			—			—			—			—
	Foreign exchange loss		(499		)	(869		)	(720		)	(712		)	(2,800		)
	Income before provision for income taxes		15,667			17,435			20,356			23,312			76,770
	Provision for income taxes		2,987			3,317			3,919			4,553			14,776
	Net income		$	12,680		$	14,118		$	16,437		$	18,759		$	61,994
	Comprehensive income		$	10,337		$	13,073		$	19,412		$	18,361		$	61,183
	Basic net income per share(1)		$	0.28		$	0.31		$	0.36		$	0.4		$	1.35
	Diluted net income per share(1)		$	0.27		$	0.29		$	0.34		$	0.38		$	1.28
	-1	Earnings per share amounts for each quarter may not necessarily total to the yearly earnings per share due to the weighting of shares outstanding on a quarterly and year to date basis.

NATURE_OF_BUSINESS_AND_SIGNIFI3

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Revenue Recognition) (Details) (Sales Revenue, Net, Product Concentration Risk)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Time and Material Contracts
Concentration Risk [Line Items]
Percentage of total revenues	84.70%	82.30%	84.10%
Fixed Price Contracts
Concentration Risk [Line Items]
Percentage of total revenues	13.60%	15.70%	13.70%

NATURE_OF_BUSINESS_AND_SIGNIFI4

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Allowance for Doubtful Accounts) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Period	$1,800	$2,203	$2,250
Charged to Costs and Expenses	1,325	619	1,244
Deductions/ Other	-944	-1,022	-1,291
Balance at End of Year	$2,181	$1,800	$2,203

NATURE_OF_BUSINESS_AND_SIGNIFI5

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Property and Equipment) (Details)	12 Months Ended
	Dec. 31, 2014
Minimum
Property, Plant and Equipment [Line Items]
Useful Life (in years)	3 years
Maximum
Property, Plant and Equipment [Line Items]
Useful Life (in years)	50 years

NATURE_OF_BUSINESS_AND_SIGNIFI6

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Goodwill and Other Intangible Assets) (Details)	12 Months Ended
	Dec. 31, 2014
	unit
Accounting Policies [Abstract]
Number of reporting units	3

NATURE_OF_BUSINESS_AND_SIGNIFI7

NATURE OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES (Risks and Uncertainties) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Concentration Risk [Line Items]
Revenues	$730,027,000	$555,117,000	$433,799,000
Customer Concentration Risk | Unbilled Revenues | UBS AG
Concentration Risk [Line Items]
Concentration risk percentage	16.50%
Number of customers	1
Customer Concentration Risk | Accounts Receivable Billed
Concentration Risk [Line Items]
Number of customers	0
Customer Concentration Risk | Sales Revenue, Net
Concentration Risk [Line Items]
Number of customers		0
Customer Concentration Risk | Sales Revenue, Net | UBS AG
Concentration Risk [Line Items]
Number of customers	1
Revenues	97,600,000
Customer Concentration Risk | Sales Revenue, Net | Top Five Customers
Concentration Risk [Line Items]
Concentration risk percentage	32.80%	30.60%	31.00%
Number of customers	5
Revenues	239,396,000	169,987,000	134,484,000
Customer Concentration Risk | Sales Revenue, Net | Top Ten Customers
Concentration Risk [Line Items]
Concentration risk percentage	43.90%	42.30%	44.40%
Number of customers	10
Revenues	320,126,000	234,955,000	192,426,000
Supplier Concentration Risk | Cost of Goods Sold and Sales, General and Administrative Expenses
Concentration Risk [Line Items]
Subcontractor costs	1,885,000	2,078,000	3,535,000
CIS Countries | Geographic Concentration Risk | Assets, Total
Concentration Risk [Line Items]
Cash	59,300,000
Belarus | Geographic Concentration Risk | Assets, Total
Concentration Risk [Line Items]
Cash	$34,200,000

ACQUISITIONS_Earnout_Obligatio

ACQUISITIONS (Earnout Obligation) (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 05, 2014	Apr. 30, 2014	Jun. 06, 2014	Oct. 31, 2014
Business Acquisition [Line Items]
Cash, Net of Working Capital and Other Adjustments, Deferred	$4,000,000	$0	$0
Netsoft
Business Acquisition [Line Items]
Cash, Net of Working Capital and Other Adjustments, Paid				2,373,000
Cash, Net of Working Capital and Other Adjustments, Deferred				1,022,000
Recorded Earnout Payable, Cash				1,825,000
Recorded Earnout Payable, Stock				0
Total Recorded Purchase Price				5,220,000
Netsoft | Common Stock
Business Acquisition [Line Items]
Common Shares, Issued (in shares)				0
Common Shares, Deferred (in shares)				0
Fair Value of Common Shares, Issued				0
Fair Value of Common Shares, Deferred				0
Netsoft | Maximum
Business Acquisition [Line Items]
Maximum Potential Earnout Payable				1,825,000
Jointech
Business Acquisition [Line Items]
Cash, Net of Working Capital and Other Adjustments, Paid					10,000,000
Cash, Net of Working Capital and Other Adjustments, Deferred					4,000,000
Recorded Earnout Payable, Cash					15,000,000
Recorded Earnout Payable, Stock					5,000,000
Total Recorded Purchase Price					36,788,000
Jointech | Common Stock
Business Acquisition [Line Items]
Common Shares, Issued (in shares)					0
Common Shares, Deferred (in shares)					89,552
Fair Value of Common Shares, Issued					0
Fair Value of Common Shares, Deferred					2,788,000
Jointech | Maximum
Business Acquisition [Line Items]
Maximum Potential Earnout Payable					20,000,000
GGA
Business Acquisition [Line Items]
Cash, Net of Working Capital and Other Adjustments, Paid						14,892,000
Cash, Net of Working Capital and Other Adjustments, Deferred						0
Recorded Earnout Payable, Cash						11,400,000
Recorded Earnout Payable, Stock						0
Total Recorded Purchase Price						26,292,000
GGA | Common Stock
Business Acquisition [Line Items]
Common Shares, Issued (in shares)						0
Common Shares, Deferred (in shares)						0
Fair Value of Common Shares, Issued						0
Fair Value of Common Shares, Deferred						0
Great Fridays
Business Acquisition [Line Items]
Cash, Net of Working Capital and Other Adjustments, Paid							10,854,000
Cash, Net of Working Capital and Other Adjustments, Deferred							0
Recorded Earnout Payable, Cash							1,173,000
Recorded Earnout Payable, Stock						0
Total Recorded Purchase Price							12,027,000
Great Fridays | Common Stock
Business Acquisition [Line Items]
Common Shares, Issued (in shares)							0
Common Shares, Deferred (in shares)							0
Fair Value of Common Shares, Issued						0
Fair Value of Common Shares, Deferred						0
Great Fridays | Maximum
Business Acquisition [Line Items]
Maximum Potential Earnout Payable					1,173,000
Total
Business Acquisition [Line Items]
Cash, Net of Working Capital and Other Adjustments, Paid	38,119,000
Cash, Net of Working Capital and Other Adjustments, Deferred	5,022,000
Recorded Earnout Payable, Cash	29,398,000
Recorded Earnout Payable, Stock	5,000,000
Total Recorded Purchase Price	80,327,000
Total | Common Stock
Business Acquisition [Line Items]
Common Shares, Issued (in shares)	0
Common Shares, Deferred (in shares)	89,552
Fair Value of Common Shares, Issued	0
Fair Value of Common Shares, Deferred	$2,788,000

ACQUISITIONS_Narrative_Details

ACQUISITIONS (Narrative) (Details) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Mar. 05, 2014	Apr. 30, 2014	Jun. 06, 2014	Oct. 31, 2014
		ITprofessional	ITprofessional	ITprofessional	CreativeProfessional
			D
			Owner
Minimum
Business Acquisition [Line Items]
Estimated future operating results period, subsequent to acquisition date (in months)	7 months
Maximum
Business Acquisition [Line Items]
Estimated future operating results period, subsequent to acquisition date (in months)	12 months
Netsoft
Business Acquisition [Line Items]
Number of professionals		40
Cash in escrow		$256,000
Purchase price adjustments	378,000
Jointech
Business Acquisition [Line Items]
Number of professionals			216
Evaluation period (in days)			30
Number of former owners			2
Consideration in escrow (as a percent)			15.00%
GGA
Business Acquisition [Line Items]
Number of professionals				329
Purchase price adjustments	-1,366,000
Great Fridays
Business Acquisition [Line Items]
Number of professionals					50
Percent of equity interest acquired					100.00%
Employment Shares
Business Acquisition [Line Items]
Estimate value of shares		1,017,000
Employment Shares | Netsoft
Business Acquisition [Line Items]
Share vesting term (in years)	3 years	3 years
Employment Shares | Jointech
Business Acquisition [Line Items]
Share vesting term (in years)	3 years
Estimate value of shares			7,788,000
Cash in escrow period (in months)	18 months
Employment Shares | GGA
Business Acquisition [Line Items]
Share vesting term (in years)	3 years
Estimate value of shares				20,655,000
Employment Shares | Great Fridays
Business Acquisition [Line Items]
Share vesting term (in years)	3 years
Estimate value of shares					4,823,000
Consideration place in escrow, value, shares					28,390
Employment Shares, Closing Shares | Netsoft
Business Acquisition [Line Items]
Stock issued (in shares)		2,289
Deferred stock issued (in shares)		9,154
Cash in escrow period (in months)		18 months
Employment Shares, Closing Shares | Jointech
Business Acquisition [Line Items]
Stock issued (in shares)			89,552
Employment Shares, Closing Shares | GGA
Business Acquisition [Line Items]
Stock issued (in shares)				262,277
Consideration in escrow (in shares)				102,631
Employment Shares, Closing Shares | Great Fridays
Business Acquisition [Line Items]
Stock issued (in shares)					90,864
Estimate value of shares					10,092
Employment Shares, Earn-Out Shares | Netsoft | Maximum
Business Acquisition [Line Items]
Stock issued (in shares)		16,349
Employment Shares, Earn-Out Shares | Jointech | Maximum
Business Acquisition [Line Items]
Estimate value of shares			5,000,000
Common Stock | Netsoft
Business Acquisition [Line Items]
Stock issued (in shares)		0
Estimate value of shares		0
Common Stock | Jointech
Business Acquisition [Line Items]
Stock issued (in shares)			0
Estimate value of shares			0
Common Stock | GGA
Business Acquisition [Line Items]
Stock issued (in shares)				0
Estimate value of shares				0
Common Stock | Great Fridays
Business Acquisition [Line Items]
Stock issued (in shares)					0
Estimate value of shares				0

ACQUISITIONS_Estimated_Fair_Va

ACQUISITIONS (Estimated Fair Values) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 05, 2014	Apr. 30, 2014	Jun. 06, 2014
Business Acquisition [Line Items]
Goodwill	$57,417,000	$22,268,000	$22,698,000
Netsoft
Business Acquisition [Line Items]
Cash and cash equivalents	0			0
Trade receivables and other current assets	788,000			788,000
Property and equipment and other long-term assets	52,000			52,000
Deferred tax asset	0			351,000
Acquired intangible assets	1,700,000			1,700,000
Goodwill	2,749,000			2,776,000
Total assets acquired	5,289,000			5,667,000
Accounts payable and accrued expenses	69,000			69,000
Deferred revenue	0			0
Due to employees	0			0
Deferred tax liability	0			0
Total liabilities assumed	69,000			69,000
Net assets acquired	5,220,000			5,598,000
Jointech
Business Acquisition [Line Items]
Cash and cash equivalents	871,000				871,000
Trade receivables and other current assets	784,000				784,000
Property and equipment and other long-term assets	338,000				338,000
Deferred tax asset	0				0
Acquired intangible assets	22,485,000				25,744,000
Goodwill	17,404,000				11,033,000
Total assets acquired	41,882,000				38,770,000
Accounts payable and accrued expenses	728,000				728,000
Deferred revenue	0				0
Due to employees	1,254,000				1,254,000
Deferred tax liability	3,112,000				0
Total liabilities assumed	5,094,000				1,982,000
Net assets acquired	36,788,000				36,788,000
GGA
Business Acquisition [Line Items]
Cash and cash equivalents	0					0
Trade receivables and other current assets	5,471,000					5,157,000
Property and equipment and other long-term assets	444,000					444,000
Deferred tax asset	0					4,463,000
Acquired intangible assets	10,959,000					10,959,000
Goodwill	12,115,000					6,496,000
Total assets acquired	28,989,000					27,519,000
Accounts payable and accrued expenses	2,593,000					2,593,000
Deferred revenue	104,000					0
Due to employees	0					0
Deferred tax liability	0					0
Total liabilities assumed	2,697,000					2,593,000
Net assets acquired	26,292,000					24,926,000
Great Fridays
Business Acquisition [Line Items]
Cash and cash equivalents	259,000
Trade receivables and other current assets	1,825,000
Property and equipment and other long-term assets	262,000
Deferred tax asset	0
Acquired intangible assets	5,747,000
Goodwill	6,947,000
Total assets acquired	15,040,000
Accounts payable and accrued expenses	872,000
Deferred revenue	317,000
Due to employees	624,000
Deferred tax liability	1,200,000
Total liabilities assumed	3,013,000
Net assets acquired	12,027,000
As Originally Reported
Business Acquisition [Line Items]
Cash and cash equivalents	1,130,000
Trade receivables and other current assets	8,554,000
Property and equipment and other long-term assets	1,096,000
Deferred tax asset	4,814,000
Acquired intangible assets	44,150,000
Goodwill	27,252,000
Total assets acquired	86,996,000
Accounts payable and accrued expenses	4,262,000
Deferred revenue	317,000
Due to employees	1,878,000
Deferred tax liability	1,200,000
Total liabilities assumed	7,657,000
Net assets acquired	79,339,000
Total
Business Acquisition [Line Items]
Cash and cash equivalents	1,130,000
Trade receivables and other current assets	8,868,000
Property and equipment and other long-term assets	1,096,000
Deferred tax asset	0
Acquired intangible assets	40,891,000
Goodwill	39,215,000
Total assets acquired	91,200,000
Accounts payable and accrued expenses	4,262,000
Deferred revenue	421,000
Due to employees	1,878,000
Deferred tax liability	4,312,000
Total liabilities assumed	10,873,000
Net assets acquired	$80,327,000

ACQUISITIONS_Intangible_Assets

ACQUISITIONS (Intangible Assets) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Netsoft
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$1,700
Jointech
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	22,485
GGA
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	10,959
Great Fridays
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	5,747
Customer relationships | Netsoft
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Finite-lived Intangible Assets Acquired	1,700
Customer relationships | Jointech
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Finite-lived Intangible Assets Acquired	22,173
Customer relationships | GGA
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Finite-lived Intangible Assets Acquired	10,959
Customer relationships | Great Fridays
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Finite-lived Intangible Assets Acquired	5,747
Trade names | Netsoft
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	0
Trade names | Jointech
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	2 years
Finite-lived Intangible Assets Acquired	312
Trade names | GGA
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	0
Trade names | Great Fridays
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-lived Intangible Assets Acquired	$0

ACQUISITIONS_Income_Statement_

ACQUISITIONS (Income Statement) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Revenues									$730,027	$555,117	$433,799
Net income	18,423	19,040	14,814	17,364	18,759	16,437	14,118	12,680	69,641	61,994	54,484
Netsoft
Business Acquisition [Line Items]
Revenues									5,068
Net income									806
Acquisition related costs									75
Stock-based compensation expense									252
Jointech
Business Acquisition [Line Items]
Revenues									13,060
Net income									-3,090
Acquisition related costs									361
Stock-based compensation expense									1,738
GGA
Business Acquisition [Line Items]
Revenues									19,809
Net income									822
Acquisition related costs									325
Stock-based compensation expense									4,322
Great Fridays
Business Acquisition [Line Items]
Revenues									1,821
Net income									-72
Acquisition related costs									24
Stock-based compensation expense									239
Total
Business Acquisition [Line Items]
Revenues									39,758	46,500
Net income									-1,534
Acquisition related costs									$785

GOODWILL_AND_INTANGIBLE_ASSETS2

GOODWILL AND INTANGIBLE ASSETS (Goodwill Roll Forward) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 05, 2014	Apr. 30, 2014	Jun. 06, 2014
Goodwill [Roll Forward]
Balance beginning of period				$22,268,000				$22,698,000	$22,268,000	$22,698,000
Goodwill written-off	-2,241,000	0	0	0	0	0	0	0	-2,241,000	0	0
Net effect of foreign currency exchange rate changes									-1,825,000	-430,000
Balance end of period	57,417,000				22,268,000				57,417,000	22,268,000	22,698,000
North America
Goodwill [Roll Forward]
Balance beginning of period				16,438,000				16,643,000	16,438,000	16,643,000
Goodwill written-off									0
Net effect of foreign currency exchange rate changes									-224,000	-205,000
Balance end of period	31,078,000				16,438,000				31,078,000	16,438,000
Europe
Goodwill [Roll Forward]
Balance beginning of period				2,864,000				2,864,000	2,864,000	2,864,000
Goodwill written-off									0
Net effect of foreign currency exchange rate changes									-876,000	0
Balance end of period	26,339,000				2,864,000				26,339,000	2,864,000
Russia
Goodwill [Roll Forward]
Balance beginning of period				2,966,000				3,191,000	2,966,000	3,191,000
Goodwill written-off									-2,241,000
Net effect of foreign currency exchange rate changes									-725,000	-225,000
Balance end of period	0				2,966,000				0	2,966,000
Netsoft
Goodwill [Roll Forward]
Balance beginning of period												2,776,000
Acquisition									2,749,000
Balance end of period	2,749,000								2,749,000			2,776,000
Netsoft | North America
Goodwill [Roll Forward]
Acquisition									2,749,000
Netsoft | Europe
Goodwill [Roll Forward]
Acquisition									0
Netsoft | Russia
Goodwill [Roll Forward]
Acquisition									0
Jointech
Goodwill [Roll Forward]
Balance beginning of period													11,033,000
Acquisition									17,404,000
Balance end of period	17,404,000								17,404,000				11,033,000
Jointech | North America
Goodwill [Roll Forward]
Acquisition									0
Jointech | Europe
Goodwill [Roll Forward]
Acquisition									17,404,000
Jointech | Russia
Goodwill [Roll Forward]
Acquisition									0
GGA
Goodwill [Roll Forward]
Balance beginning of period														6,496,000
Acquisition									12,115,000
Balance end of period	12,115,000								12,115,000					6,496,000
GGA | North America
Goodwill [Roll Forward]
Acquisition									12,115,000
GGA | Europe
Goodwill [Roll Forward]
Acquisition									0
GGA | Russia
Goodwill [Roll Forward]
Acquisition									0
Great Fridays
Goodwill [Roll Forward]
Acquisition									6,947,000
Balance end of period	6,947,000								6,947,000
Great Fridays | North America
Goodwill [Roll Forward]
Acquisition									0
Great Fridays | Europe
Goodwill [Roll Forward]
Acquisition									6,947,000
Great Fridays | Russia
Goodwill [Roll Forward]
Acquisition									$0

GOODWILL_AND_INTANGIBLE_ASSETS3

GOODWILL AND INTANGIBLE ASSETS (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Goodwill	$57,417,000				$22,268,000				$57,417,000	$22,268,000	$22,698,000
Goodwill impairment loss	2,241,000	0	0	0	0	0	0	0	2,241,000	0	0
North America
Goodwill [Line Items]
Goodwill	31,078,000				16,438,000				31,078,000	16,438,000	16,643,000
Goodwill impairment loss									0
Accumulated impairment loss	0				0				0	0	0
Europe
Goodwill [Line Items]
Goodwill	26,339,000				2,864,000				26,339,000	2,864,000	2,864,000
Goodwill impairment loss									0
Accumulated impairment loss	0				0				0	0	0
Russia
Goodwill [Line Items]
Goodwill	0				2,966,000				0	2,966,000	3,191,000
Goodwill impairment loss									2,241,000
Other
Goodwill [Line Items]
Goodwill	0				0				0	0	0
Accumulated impairment loss	$1,697,000								$1,697,000

GOODWILL_AND_INTANGIBLE_ASSETS4

GOODWILL AND INTANGIBLE ASSETS (Goodwill, Net) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$55,667	$20,512	$20,977
Accumulated amortization	-7,978	-6,778	-4,143
Net carrying amount	47,689	13,734	16,834
Amortization of Intangible Assets	5,349	2,785	1,024
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Weighted average life at acquisition (in years)	10 years	9 years	9 years
Gross carrying amount	48,482	13,432	13,724
Accumulated amortization	-4,664	-4,885	-3,640
Net carrying amount	43,818	8,547	10,084
Amortization of Intangible Assets	3,843	1,373	627
Trade name
Finite-Lived Intangible Assets [Line Items]
Weighted average life at acquisition (in years)	5 years	5 years	5 years
Gross carrying amount	6,372	6,232	6,372
Accumulated amortization	-2,894	-1,643	-439
Net carrying amount	3,478	4,589	5,933
Amortization of Intangible Assets	1,319	1,222	333
Non-competition agreements
Finite-Lived Intangible Assets [Line Items]
Weighted average life at acquisition (in years)	5 years	5 years	5 years
Gross carrying amount	813	848	881
Accumulated amortization	-420	-250	-64
Net carrying amount	393	598	817
Amortization of Intangible Assets	$187	$190	$64

GOODWILL_AND_INTANGIBLE_ASSETS5

GOODWILL AND INTANGIBLE ASSETS (Estimated Amortization Expense) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2015	$6,520
2016	6,383
2017	5,957
2018	5,032
2019	4,748
Thereafter	19,049
Net carrying amount	$47,689	$13,734	$16,834

PREPAID_AND_OTHER_CURRENT_ASSE2

PREPAID AND OTHER CURRENT ASSETS (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Taxes receivable	$3,966	$7,295
Prepaid expenses	3,703	3,399
Security deposits under operating leases	476	1,005
Prepaid equipment	185	986
Unamortized software licenses and subscriptions	454	981
Due from employees	96	218
Other	409	471
Total	$9,289	$14,355

EMPLOYEE_LOANS_AND_ALLOWANCE_F2

EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES (Employee Loans) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total employee loans	$6,515	$6,390
Less: Allowance for loan losses	0	0
Total loans, net of allowance for loan losses	6,515	6,390
Housing loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total employee loans	5,848	5,896
Relocation and other loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total employee loans	$667	$494

EMPLOYEE_LOANS_AND_ALLOWANCE_F3

EMPLOYEE LOANS AND ALLOWANCE FOR LOAN LOSSES (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans issued to principal officers, directors, or their affiliates	$0	$0	$0
Loans Under Employee Housing Program
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum service period for employee housing program	3 years
Loans authorized for issuance, amount	10,000,000
Loan term (in years)	5 years
Interest rate on loan (as a percent)	7.50%
Material loans past due	0	0
Non-accrual employee loans	0	0
Provision for loan losses	0	0	0
Loans Under Employee Housing Program, Individual Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans authorized for issuance, amount	$50

Schedule_of_Restricted_Cash_an

(Schedule of Restricted Cash and Time Deposits) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Cash and Cash Equivalents [Line Items]
Time deposits	$0	$1,188
Short-term security deposits under customer contracts	0	298
Long-term deposits	156	225
Total	156	1,711
Time deposits
Cash and Cash Equivalents [Line Items]
Time deposits	0	1,188
Short-term security deposits under customer contracts
Cash and Cash Equivalents [Line Items]
Short-term security deposits under customer contracts	0	298
Long-term deposits under employee loan programs
Cash and Cash Equivalents [Line Items]
Long-term deposits	156	225
Long-term deposits under operating leases
Cash and Cash Equivalents [Line Items]
Long-term deposits	$0	$0

RESTRICTED_CASH_AND_TIME_DEPOS2

RESTRICTED CASH AND TIME DEPOSITS (Narrative) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Cash and Cash Equivalents [Line Items]
Time deposits	$0	$1,188,000
Long-term deposits	156,000	225,000
Provision for losses under customer contracts secured by ST deposits	0	0
Time deposits
Cash and Cash Equivalents [Line Items]
Time deposits	0	1,188,000
Interest rate (as a percent)		2.05%
Long-term deposits under employee loan programs
Cash and Cash Equivalents [Line Items]
Long-term deposits	$156,000	$225,000

PROPERTY_AND_EQUIPMENT_NET_Det

PROPERTY AND EQUIPMENT - NET (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$89,666	$83,479
Less accumulated depreciation and amortization	-34,532	-30,164
Total	55,134	53,315
Depreciation and amortization expenses	12,134	12,335	9,858
Computer hardware
Property, Plant and Equipment [Line Items]
Useful Life (in years)	3 years
Property, Plant and Equipment, Gross	32,374	29,884
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	6,287	5,903
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful Life (in years)	7 years
Property, Plant and Equipment, Gross	7,348	5,688
Purchased computer software
Property, Plant and Equipment [Line Items]
Useful Life (in years)	3 years
Property, Plant and Equipment, Gross	3,606	5,042
Office equipment
Property, Plant and Equipment [Line Items]
Useful Life (in years)	7 years
Property, Plant and Equipment, Gross	5,043	4,679
Building
Property, Plant and Equipment [Line Items]
Useful Life (in years)	50 years
Property, Plant and Equipment, Gross	17,123	16,534
Construction in Progress
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$17,885	$15,749

ACCRUED_EXPENSES_AND_OTHER_LIA2

ACCRUED EXPENSES AND OTHER LIABILITIES (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]
Compensation	$22,766	$13,674
Acquisition related deferred consideration	1,022	0
Subcontractor costs	2,815	2,933
Professional fees	1,162	947
Facilities costs	757	334
Other	3,681	2,287
Total	$32,203	$20,175

TAXES_PAYABLE_TAXES_PAYABLE_De

TAXES PAYABLE TAXES PAYABLE (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ComponentsOfTaxesOtherThanIncome [Abstract]
Corporate profit tax	$7,982	$3,717
Value added taxes	6,279	5,975
Payroll, social security, and other taxes	10,443	4,479
Total	$24,704	$14,171

INCOME_TAXES_Provision_for_Inc

INCOME TAXES (Provision for Income Taxes) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income before income tax expense:
Domestic									($7,229)	$7,001	$9,291
Foreign									94,182	69,769	56,572
Income before provision for income taxes	$24,582	$22,378	$18,401	$21,592	$23,312	$20,356	$17,435	$15,667	$86,953	$76,770	$65,863

INCOME_TAXES_Income_Tax_Expens

INCOME TAXES (Income Tax Expense (Benefit) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current
Federal									$7,741	$6,150	$6,881
State									338	310	319
Foreign									12,504	8,275	7,969
Deferred
Federal									-3,979	-668	-625
State									-43	14	24
Foreign									751	695	-3,189
Total	$6,159	$3,338	$3,587	$4,228	$4,553	$3,919	$3,317	$2,987	$17,312	$14,776	$11,379

INCOME_TAXES_Deferred_Tax_Asse

INCOME TAXES (Deferred Tax Assets and Liabilities) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Fixed assets	$181	$732
Intangible assets	3,789	4,532
Accrued expenses	1,282	3,488
Net operating loss carryforward	844	0
Deferred revenue	4,328	2,050
Stock-based compensation	6,994	407
Valuation allowance	-149	0
Restricted stock options	2	1,336
Other assets	30	680
Deferred tax assets	17,301	13,225
Deferred tax liabilities:
Fixed assets	800	804
Accrued revenue and expenses	635	846
Deferred inter-company gain	405	405
Equity compensation	7,013	1,593
Other liabilities	24	254
Deferred tax liability	8,877	3,902
Net deferred tax asset	8,424	9,323
Deferred Tax Assets Classification
Deferred tax assets, current	2,496	5,392
Deferred tax assets, long-term	11,094	4,557
Deferred Tax Liabilities Classification
Net deferred tax liabilities, current	603	275
Net deferred tax liabilities, noncurrent	$4,563	$351

INCOME_TAXES_Effective_Income_

INCOME TAXES (Effective Income Tax Reconciliation) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Statutory federal tax									$29,564	$26,102	$22,393
Increase/ (decrease) in taxes resulting from:
State taxes, net of federal benefit									311	368	280
Provision adjustment for current year uncertain tax position									-1,220	0	0
Effect of permanent differences									8,589	2,524	2,177
Stock-based compensation									3,782	1,948	1,165
Rate differential between U.S. and foreign									-24,772	-17,279	-14,472
Change in foreign tax rate									754	-59	148
Change in valuation allowance									149	489	-489
Other									155	683	177
Total	$6,159	$3,338	$3,587	$4,228	$4,553	$3,919	$3,317	$2,987	$17,312	$14,776	$11,379

INCOME_TAXES_Narrative_Details

INCOME TAXES (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Holiday [Line Items]
Undistributed Earnings of Foreign Subsidiaries	$340,500,000
Aggregate dollar benefits from tax holidays	16,800,000	9,700,000	8,500,000
Income tax holiday benefit (in dollars per share)	$0.34	$0.20	$0.19
Unrecognized tax benefits	200,000	1,271,000	1,271,000	1,271,000
Penalties and interest	12,000	189,000	125,000
Unrecognized tax benefits with favorable impact	$212,000	$1,328,000
Belarus
Income Tax Holiday [Line Items]
Exemption (as a percent)	100.00%
Federal income tax rate (as a percent)	18.00%
Tax exemption period (in years)	15 years
Income tax holiday description	On September 22, 2005, the president of Belarus signed the decree “On the High-Technologies Park” (the “Decree”). The Decree is aimed at boosting the country’s high-technology sector. The Decree stipulates that member technology companies have a 100% exemption from Belarusian income tax of 18% effective July 1, 2006. The Decree is in effect for a period of 15 years from July 1, 2006.
Hungary
Income Tax Holiday [Line Items]
Tax exemption period (in years)	4 years
Income tax credit (as a percent)	70.00%
Income tax holiday description	The Company’s subsidiary in Hungary benefits from a tax credit of 10% of annual qualified salaries, taken over a 4-year period, for up to 70% of the total tax due for that period. The Company has been able to take the full 70% credit for 2008 - 2014. The Hungarian tax authorities repealed the tax credit beginning with 2012. However, credits earned in the years prior to 2012, will be allowed to be used through 2014. The Company has utilized the 70% limit through 2014.
Tax credit on annual qualified salaries (as a percent)	10.00%

INCOME_TAXES_Unrecognized_Tax_

INCOME TAXES (Unrecognized Tax Benefits) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$1,271	$1,271	$1,271
Increases in tax positions in current year	0	0	0
Increases in tax positions in prior year	0	0	0
Decreases due to settlement	-1,071	0	0
Balance at end of period	$200	$1,271	$1,271

EMPLOYEE_BENEFITS_Details

EMPLOYEE BENEFITS (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Discretionary matching contribution to retirement plan by employer (as a percent)	2.00%
Contribution by employer for retirement plan	$549	$404

LONGTERM_DEBT_Details

LONG-TERM DEBT (Details) (USD $)	0 Months Ended	12 Months Ended	0 Months Ended
	Jan. 15, 2013	Dec. 31, 2014	Sep. 12, 2014
2013 Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	40,000,000
2013 Credit Facility | LIBOR | Revolving Credit Facility
Debt Instrument [Line Items]
Variable rate spread (as a percent)	1.25%
2014 Credit Facility
Debt Instrument [Line Items]
Line of credit, current borrowing capacity		100,000,000
2014 Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity			200,000,000
Line of credit, maximum borrowing capacity in foreign currency			50,000,000
Percentage of foreign subsidiaries outstanding shares of capital stock serves as collateral		65.00%
Line of credit, current borrowing capacity			100,000,000
Outstanding debt		$0
2014 Credit Facility | LIBOR | Revolving Credit Facility
Debt Instrument [Line Items]
Variable rate spread (as a percent)			1.00%
2014 Credit Facility | Federal Funds Open Rate | Revolving Credit Facility
Debt Instrument [Line Items]
Variable rate spread (as a percent)			0.50%

COMMON_AND_PREFERRED_STOCK_IPO

COMMON AND PREFERRED STOCK (IPO and Other Transactions) (Details) (USD $)	0 Months Ended	12 Months Ended			3 Months Ended	1 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 19, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Feb. 29, 2012	Feb. 07, 2012
Class of Stock [Line Items]
Common stock, stock split ratio	8
Common stock, shares authorized	160,000,000	160,000,000	160,000,000
Preferred stock, shares authorized	40,000,000
Common stock issued (in shares)		48,748,298	47,569,463				2,900,000
Payment for stock issuance costs		$0	$0	$1,765
Instant Information Inc
Class of Stock [Line Items]
Stock issued in connection with acquisition (in shares)					53,336
Stock issued in connection with acquisition				640	640
IPO
Class of Stock [Line Items]
Common stock sold (in shares)						6,900,000
Gross proceeds from issuance of common stock						34,800
Conversion of preferred stock (in shares)						21,840,128
IPO | Common Stock
Class of Stock [Line Items]
Common stock sold pursuant to over-allotment option granted to underwriters (in shares)						900,000
Sale of stock price per share (in dollars per share)							12
Net proceeds from issuance of stock						28,969
IPO | Stockholders
Class of Stock [Line Items]
Common stock sold (in shares)						4,000,000
IPO | Underwriting Discounts and Commissions
Class of Stock [Line Items]
Payment for stock issuance costs						2,436
IPO | Offering expenses
Class of Stock [Line Items]
Payment for stock issuance costs						$3,395

COMMON_AND_PREFERRED_STOCK_Con

COMMON AND PREFERRED STOCK (Conversion of Preferred Stock) (Details) (IPO)	1 Months Ended
	Feb. 29, 2012
Class of Stock [Line Items]
Conversion of preferred stock (in shares)	21,840,128
Series A-1 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Conversion of preferred stock (in shares)	16,439,480
Series A-2 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Conversion of preferred stock (in shares)	3,078,432
Series A-3 Convertible Preferred Stock
Class of Stock [Line Items]
Conversion of preferred stock (in shares)	2,322,216

COMMON_AND_PREFERRED_STOCK_Ser

COMMON AND PREFERRED STOCK (Series A-1 Preferred) (Details) (USD $)	0 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 20, 2006	Dec. 31, 2014	Dec. 31, 2011	Jan. 20, 2006
		vote
Class of Stock [Line Items]
Deemed dividend	6,803			6,803
Series A-1 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Issuance of preferred stock (in shares)	657,354			657,354
Compounded annual rate of return (as a percent)	12.50%
Number of votes		1
Redemption value			41,245
Private Placement
Class of Stock [Line Items]
Common stock converted to preferred stock (in shares)	11,180,648
Private Placement | Common Stock
Class of Stock [Line Items]
Sale of stock price per share (in dollars per share)	1.13			1.13
Private Placement | Series A-1 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Sale of stock price per share (in dollars per share)	12.17			12.17
Number of installments		4
Net proceeds from issuance of stock	8,000
Stock issued during period shares convertible preferred new issues (in shares)	1,397,581
Minimum | Private Placement | Series A-1 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Redemption period (in years)		30
Maximum | Private Placement | Series A-1 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Redemption period (in days)		1 year 6 months

COMMON_AND_PREFERRED_STOCK_Ser1

COMMON AND PREFERRED STOCK (Series A-2 Preferred) (Details) (USD $)	12 Months Ended			0 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 19, 2010	Feb. 19, 2008
Class of Stock [Line Items]
Payment for stock issuance costs	$0	$0	$1,765
Series A-2 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Issuance of preferred stock (in shares)				290,277	675,081
Repurchase and retirement of Series A-2 convertible redeemable preferred stock				15,050
Percentage of equity securities subject to liquidation evaluation				100.00%
Compounded annual rate of return (as a percent)				12.50%
Percentage of liquidation price to cash and non-cash proceeds				17.10%
Maximum | Series A-2 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Compounded annual rate of return (as a percent)				18.00%
Minimum | Series A-2 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Number of installments	3
Compounded annual rate of return, hurdle rate (as a percent)				17.00%
Private Placement | Series A-2 Convertible Redeemable Preferred Stock
Class of Stock [Line Items]
Net proceeds from issuance of stock					47,601
Gross proceeds from issuance of preferred stock					50,000
Payment for stock issuance costs					$2,399
Sale of stock price per share (in dollars per share)				$51.85	$74.07
Number of votes	1

COMMON_AND_PREFERRED_STOCK_Ser2

COMMON AND PREFERRED STOCK (Series A-3 Preferred) (Details) (Series A-3 Convertible Preferred Stock, USD $)	0 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Apr. 15, 2010	Dec. 31, 2014	Apr. 15, 2010
		vote
Class of Stock [Line Items]
Issuance of preferred stock (in shares)	290,277		290,277
Percentage of equity securities subject to liquidation evaluation	100.00%
Private Placement
Class of Stock [Line Items]
Sale of stock price per share (in dollars per share)	$51.85		$51.85
Net proceeds from issuance of stock	$14,971
Number of votes		1

COMMON_AND_PREFERRED_STOCK_Tre

COMMON AND PREFERRED STOCK (Treasury Stock) (Details)	12 Months Ended
	Dec. 31, 2012
Equity [Abstract]
Treasury stock retired (in shares)	38,792

STOCKBASED_COMPENSATION_Costs_

STOCK-BASED COMPENSATION (Costs Related to Stock Compensation Plans) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$24,620	$13,150	$6,826
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	8,648	4,823	2,809
Selling, general and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$15,972	$8,327	$4,017

STOCKBASED_COMPENSATION_Equity

STOCK-BASED COMPENSATION (Equity Plans) (Details) (USD $)	0 Months Ended	12 Months Ended	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 11, 2012	Dec. 31, 2014	Jun. 30, 2013
2012 Directors Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized to be reserved for issuance (in shares)	600,000
2012 Directors Plan expiration period (in years)	10 years
2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares available for issuance (in shares)		4,785,761
2006 Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares subject to outstanding awards that expire or terminate that are available for awards to be granted (in shares)		1,743,034
2006 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options issued expiration period (in years)		10 years
Empathy Lab, LLC
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested common stock shares issued (in shares)			1,483
Percentage of restricted stock vested			33.33%
Fair value at grant date			$42

STOCKBASED_COMPENSATION_Stock_

STOCK-BASED COMPENSATION (Stock Option Activity) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Options (in shares)
Options outstanding, beginning of period	5,823,536	6,296,709	6,595,136
Options granted	2,400,500	1,987,952	1,443,810
Options exercised	-1,171,097	-2,156,898	-1,552,742
Options forfeited/cancelled	-214,193	-304,227	-189,495
Options outstanding, end of period	6,838,746	5,823,536	6,296,709
Options vested and exercisable at December 31, 2014	2,406,016
Options expected to vest	4,074,226
Weighted Average Exercise Price (in dollars per share)
Options outstanding, beginning of period	$13.99	$7.51	$4.65
Options granted	$32.51	$23.60	$16.80
Options exercised	$9.05	$4.31	$3.53
Options forfeited/cancelled	$25.33	$11.50	$11.35
Options outstanding, end of period	$20.98	$13.99	$7.51
Options vested and exercisable at December 31, 2014	$9.83
Options expected to vest	$26.82
Aggregate Intrinsic Value
Options outstanding, beginning of period	$122,003	$66,682	$48,447
Options granted	36,584	22,543	1,877
Options exercised	-45,321	-66,066	-22,623
Options forfeited/cancelled	-4,802	-7,131	-1,279
Options outstanding, end of period	183,073	122,003	66,682
Options vested and exercisable at December 31, 2014	91,236
Options expected to vest	$85,274

STOCKBASED_COMPENSATION_Stock_1

STOCK-BASED COMPENSATION (Stock Options) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Underlying options (in shares)	1,554
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (as a percent)	46.00%	46.00%	46.00%
Expected term (in years)	6 years 2 months 13 days	6 years 2 months 26 days	6 years 3 months
Risk free interest rate (as a percent)	2.01%	1.41%	1.13%
Dividend rate (as a percent)	0.00%	0.00%	0.00%
Unrecognized compensation cost, net of forfeitures	$41,669
Total unrecognized compensation cost related to non-vested share-based compensation awards granted, period for recognition (in years)	1 year 10 months 22 days
Weighted average remaining contractual term, exercisable (in years)	5 years 1 month 24 days
Weighted average remaining contractual term, outstanding (in years)	8 years 7 months
2012 Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate grant-date fair value of stock options	$33,004
Share vesting term (in years)	4 years

STOCKBASED_COMPENSATION_Other_

STOCK-BASED COMPENSATION (Other Awards Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Service-Based Awards
Number of Shares
Unvested awards outstanding, beginning of period	344,928	659,872	0
Awards granted	523,220	15,524	757,272
Awards vested	-217,668	-330,468	-97,400
Awards forfeited/cancelled	-17,038
Unvested awards outstanding, end of period	633,442	344,928	659,872
Weighted Average Grant Date Fair Value Per Share (in dollars per share)
Unvested awards outstanding, beginning of period	$18.74	$17.92	$0
Awards granted	$40.41	$23.69	$17.15
Awards vested	$17.84	$17.33	$12
Awards forfeited/cancelled	$21.14
Unvested awards outstanding, end of period	$36.88	$18.74	$17.92
Performance-Based Awards
Number of Shares
Unvested awards outstanding, beginning of period	0
Awards granted	387,058
Awards vested	0
Awards forfeited/cancelled	-2,550
Changes in the number of awards expected to be delivered	-12,998
Unvested awards outstanding, end of period	371,510
Weighted Average Grant Date Fair Value Per Share (in dollars per share)
Unvested awards outstanding, beginning of period	$0
Awards granted	$38.18
Awards vested	$0
Awards forfeited/cancelled	$36.57
Changes in the number of awards expected to be delivered	$5.47
Unvested awards outstanding, end of period	$39.34

STOCKBASED_COMPENSATION_Other_1

STOCK-BASED COMPENSATION (Other Awards) (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Service-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options issued (in shares)	523,220	15,524	757,272
Underlying service-based awards, unvested and outstanding (in shares)	633,442	344,928	659,872	0
Service-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to non-vested share-based compensation awards granted, period for recognition (in years)	1 year 8 months 15 days
Stock options issued (in shares)	444,982
Stock options issued, grant date fair value	18,471
Underlying service-based awards, unvested and outstanding (in shares)	545,379
Underlying options, value at grant date	20,544
Performance-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to non-vested share-based compensation awards granted	13,953
Total unrecognized compensation cost related to non-vested share-based compensation awards granted, period for recognition (in years)	1 year 9 months
Stock options issued (in shares)	387,058
Underlying service-based awards, unvested and outstanding (in shares)	371,510	0
2012 Directors Plan | Service-Based Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested common stock shares issued (in shares)	7,738
Restricted stock issued, value at grant date	325
Total unrecognized compensation cost related to non-vested share-based compensation awards granted	282
Total unrecognized compensation cost related to non-vested share-based compensation awards granted, period for recognition (in years)	1 year 6 months 19 days
2012 Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to non-vested share-based compensation awards granted	1,643
Total unrecognized compensation cost related to non-vested share-based compensation awards granted, period for recognition (in years)	2 years 2 months 1 day
Deferred compensation, shares issued	70,500
Deferred compensation arrangement, fair value of shares issued	2,295

EARNINGS_PER_SHARE_Details

EARNINGS PER SHARE (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator for common earnings per share:
Net income	$18,423	$19,040	$14,814	$17,364	$18,759	$16,437	$14,118	$12,680	$69,641	$61,994	$54,484
Net income allocated to participating securities									0	0	-3,341
Numerator for basic earnings per share									69,641	61,994	51,143
Effect on income available from reallocation of options									0	0	261
Numerator for diluted earnings per share									$69,641	$61,994	$51,404
Denominator for basic earnings per share:
Weighted average common shares outstanding (in shares)									47,189	45,754	40,190
Effect of dilutive securities:
Stock options, RSUs and performance-based awards (in shares)									2,545	2,604	3,631
Denominator for diluted earnings per share (in shares)									49,734	48,358	43,821
Net income per share:
Basic (in dollars per share)	$0.39	$0.40	$0.31	$0.37	$0.40	$0.36	$0.31	$0.28	$1.48	$1.35	$1.27
Diluted (in dollars per share)	$0.37	$0.38	$0.30	$0.35	$0.38	$0.34	$0.29	$0.27	$1.40	$1.28	$1.17
Anti-dilutive options not included in the calculation (in shares)									2,260	1,080	1,534

COMMITMENTS_AND_CONTINGENCIES_1

COMMITMENTS AND CONTINGENCIES (Future Minimum Rental Payments) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	$16,718
2016	10,482
2017	7,668
2018	4,993
2019	3,589
Thereafter	952
Total minimum lease payments	$44,402

COMMITMENTS_AND_CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES (Narrative) (Details) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014
Commitments and Contingencies [Line Items]
Operating lease expense	$18,200,000	$15,664,000	$11,594,000
Breach of Contract Against IDEAB
Commitments and Contingencies [Line Items]
Penalties	20,000
Legal settlement amount				1,000,000
Construction in Progress
Commitments and Contingencies [Line Items]
Capitalized construction costs	17,885,000
Estimate additional costs	8,200,000
Estimate of probable losses	2,593,000
Construction in Progress | Maximum
Commitments and Contingencies [Line Items]
Estimate of probable losses	4,500,000
Employee Housing Program
Commitments and Contingencies [Line Items]
Provision for losses	0	0	0
2006 Employee Loan Program
Commitments and Contingencies [Line Items]
Provision for losses	$0	$0	$0

FAIR_VALUE_MEASUREMENTS_Recurr

FAIR VALUE MEASUREMENTS (Recurring Fair Value Measurements) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Equity, Fair Value Disclosure [Abstract]
Employee housing loans	$3,162	$8,963
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

FAIR_VALUE_MEASUREMENTS_Contin

FAIR VALUE MEASUREMENTS (Contingent Consideration Roll Forward) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contractual contingent liabilities	$1,924	$0	$0	$0	$0	$0	$0	$0	$1,924	$0	$0
Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contractual contingent liabilities at January 1, 2014				0					0
Liability-classified stock-based awards									3,088
Changes in fair value of contractual contingent liabilities included in earnings									2,059
Changes in fair value of contractual contingent liabilities recorded against goodwill									1,366
Effect of net foreign currency exchange rate changes									-288
Contractual contingent liabilities at September 30, 2014	40,623								40,623
Level 3 | Netsoft
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contractual contingent liabilities									1,825
Level 3 | Jointech
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contractual contingent liabilities									20,000
Level 3 | GGA
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contractual contingent liabilities									11,400
Level 3 | Great Fridays
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contractual contingent liabilities									$1,173

OPERATING_SEGMENTS_Revenues_fr

OPERATING SEGMENTS (Revenues from External Customers and Segment Operating Profit Before Unallocated Expenses) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$202,184	$192,764	$174,695	$160,384	$157,585	$140,150	$133,184	$124,198	$730,027	$555,117	$433,799
Operating profit	24,015	21,835	18,476	21,857	23,192	20,230	17,535	15,536	86,183	76,493	66,006
Entity-wide revenue, major customer, amount									730,027	555,117	433,799
Russia
Segment Reporting Information [Line Items]
Revenues									48,945	53,328	47,507
Operating Segments
Segment Reporting Information [Line Items]
Revenues									730,003	555,043	433,722
Operating profit									144,619	109,308	87,455
Entity-wide revenue, major customer, amount									730,003	555,043	433,722
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues									374,509	284,636	197,271
Operating profit									90,616	66,814	38,671
Operating Segments | Europe
Segment Reporting Information [Line Items]
Revenues									299,279	204,150	168,913
Operating profit									50,189	34,573	32,750
Operating Segments | Russia
Segment Reporting Information [Line Items]
Revenues									50,663	55,764	50,552
Operating profit									7,034	7,077	9,049
Operating Segments | Other
Segment Reporting Information [Line Items]
Revenues									5,552	10,493	16,986
Operating profit									-3,220	844	6,985
Sales Revenue, Net | Customer Concentration Risk
Segment Reporting Information [Line Items]
Number of customers										0
Sales Revenue, Net | Customer Concentration Risk | UBS AG
Segment Reporting Information [Line Items]
Entity-wide revenue, major customer, amount									97,600
Number of customers									1
Sales Revenue, Net | Customer Concentration Risk | Europe | UBS AG
Segment Reporting Information [Line Items]
Entity-wide revenue, major customer, amount									$97,872
Unbilled Revenues | Customer Concentration Risk | UBS AG
Segment Reporting Information [Line Items]
Percentage of total revenues									16.50%
Number of customers									1
Accounts Receivable Billed | Customer Concentration Risk
Segment Reporting Information [Line Items]
Number of customers									0

OPERATING_SEGMENTS_Reconciliat

OPERATING SEGMENTS (Reconciliation of Segment Revenues and Operating Profit to Consolidated Income From Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									$730,027	$555,117	$433,799
Segment Reporting Information [Line Items]
Total segment operating profit:	24,015	21,835	18,476	21,857	23,192	20,230	17,535	15,536	86,183	76,493	66,006
Stock-based compensation expense									-24,620	-13,150	-6,826
Depreciation and amortization	-2,833	-5,510	-5,451	-3,689	-3,743	-3,906	-3,854	-3,617	-17,483	-15,120	-10,882
Provision for bad debts									-1,325	-619	-1,244
Interest and other income, net	1,368	1,261	1,164	976	832	846	769	630	4,769	3,077	1,941
Change in fair value of contingent consideration	-1,924	0	0	0	0	0	0	0	-1,924	0	0
Foreign exchange loss	1,123	-718	-1,239	-1,241	-712	-720	-869	-499	-2,075	-2,800	-2,084
Income before provision for income taxes	24,582	22,378	18,401	21,592	23,312	20,356	17,435	15,667	86,953	76,770	65,863
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									730,003	555,043	433,722
Segment Reporting Information [Line Items]
Total segment operating profit:									144,619	109,308	87,455
Unallocated Amounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									24	74	77
Segment Reporting Information [Line Items]
Other revenues									24	74	77
Stock-based compensation expense									-24,620	-13,150	-6,826
Non-corporate taxes									-6,882	-3,201	-2,346
Professional fees									-5,312	-3,651	-2,850
Depreciation and amortization									-7,988	-2,829	-1,100
Bank charges									-1,049	-1,194	-1,136
Asset impairment									-5,983	0	0
Stock charge									0	0	-640
Provision for bad debts									0	-36	0
Other corporate expenses									($6,626)	($8,828)	($6,628)

OPERATING_SEGMENTS_Geographica

OPERATING SEGMENTS (Geographical Information of Long-Lived Assets Based on Physical Location) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$55,134	$53,315
Belarus
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	41,652	38,697
Ukraine
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	4,392	5,525
Hungary
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,773	2,644
Russia
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,196	3,414
United States
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,001	2,217
Other
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$2,120	$818

OPERATING_SEGMENTS_Revenues_by

OPERATING SEGMENTS (Revenues by Client Location) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$202,184	$192,764	$174,695	$160,384	$157,585	$140,150	$133,184	$124,198	$730,027	$555,117	$433,799
Reimbursable expenses and other revenues
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									8,410	7,626	6,417
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									318,304	247,979	197,593
United Kingdom
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									141,366	108,892	98,346
Switzerland
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									87,111	51,941	30,120
Russia
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									48,945	53,328	47,507
Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									49,193	33,759	9,256
Germany
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									25,740	20,261	16,391
China
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									13,445	0	0
Netherlands
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									8,838	7,719	3,127
Sweden
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									7,892	5,742	4,913
Kazakhstan
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									5,238	9,886	11,352
Other locations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues									$15,545	$7,984	$8,777

OPERATING_SEGMENTS_Revenues_by1

OPERATING SEGMENTS (Revenues by Service Offering) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Revenues	$202,184	$192,764	$174,695	$160,384	$157,585	$140,150	$133,184	$124,198	$730,027	$555,117	$433,799
Software development
Revenue from External Customer [Line Items]
Revenues									504,590	374,426	290,139
Application testing services
Revenue from External Customer [Line Items]
Revenues									140,363	109,222	85,849
Application maintenance and support
Revenue from External Customer [Line Items]
Revenues									58,840	45,971	36,056
Infrastructure services
Revenue from External Customer [Line Items]
Revenues									14,198	14,433	12,424
Licensing
Revenue from External Customer [Line Items]
Revenues									3,626	3,439	2,914
Reimbursable expenses and other revenues
Revenue from External Customer [Line Items]
Revenues									$8,410	$7,626	$6,417

QUARTERLY_FINANCIAL_DATA_Detai

QUARTERLY FINANCIAL DATA (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Revenues	$202,184	$192,764	$174,695	$160,384	$157,585	$140,150	$133,184	$124,198	$730,027	$555,117	$433,799
Cost of revenues (exclusive of depreciation and amortization)	121,465	122,509	110,102	102,454	97,627	88,539	83,547	77,937	456,530	347,650	270,361
Selling, general and administrative expenses	49,761	42,875	38,671	32,359	32,980	27,893	28,541	27,083	163,666	116,497	85,868
Depreciation and amortization expense	2,833	5,510	5,451	3,689	3,743	3,906	3,854	3,617	17,483	15,120	10,882
Goodwill impairment loss	2,241	0	0	0	0	0	0	0	2,241	0	0
Other operating (income)/ expenses, net	1,869	35	1,995	25	43	-418	-293	25	3,924	-643	682
Total segment operating profit:	24,015	21,835	18,476	21,857	23,192	20,230	17,535	15,536	86,183	76,493	66,006
Interest and other income, net	1,368	1,261	1,164	976	832	846	769	630	4,769	3,077	1,941
Change in fair value of contingent consideration	-1,924	0	0	0	0	0	0	0	-1,924	0	0
Foreign exchange loss	1,123	-718	-1,239	-1,241	-712	-720	-869	-499	-2,075	-2,800	-2,084
Income before provision for income taxes	24,582	22,378	18,401	21,592	23,312	20,356	17,435	15,667	86,953	76,770	65,863
Provision for income taxes	6,159	3,338	3,587	4,228	4,553	3,919	3,317	2,987	17,312	14,776	11,379
Net income	18,423	19,040	14,814	17,364	18,759	16,437	14,118	12,680	69,641	61,994	54,484
Comprehensive income	$7,115	$10,780	$17,708	$13,787	$18,361	$19,412	$13,073	$10,337	$49,390	$61,183	$56,977
Basic (in dollars per share)	$0.39	$0.40	$0.31	$0.37	$0.40	$0.36	$0.31	$0.28	$1.48	$1.35	$1.27
Diluted (in dollars per share)	$0.37	$0.38	$0.30	$0.35	$0.38	$0.34	$0.29	$0.27	$1.40	$1.28	$1.17