EPAM Systems (EPAM) 10-Q 5 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-35418
Entity Registrant Name	EPAM SYSTEMS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-3536104
Entity Address, Street Name	41 University Drive
Entity Address, Suite No.	Suite 202
Entity Address, City or Town	Newtown
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	18940
City Area Code	267
Local Phone Number	759-9000
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	EPAM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Central Index Key	0001352010
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		55,988,929
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets
Cash and cash equivalents	$ 1,161,065	$ 936,552
Short-term investments	60,089	9
Trade receivables and contract assets, net of allowance of $5,371 and $2,920, respectively	493,225	497,716
Prepaid and other current assets	37,843	39,934
Total current assets	1,752,222	1,474,211
Property and equipment, net	163,689	165,259
Operating lease right-of-use assets, net	232,780	238,991
Intangible assets, net	54,321	56,258
Goodwill	207,764	195,043
Deferred tax assets	90,071	75,013
Other noncurrent assets	54,578	39,433
Total assets	2,555,425	2,244,208
Current liabilities
Accounts payable	10,785	7,831
Accrued compensation and benefits expenses	263,918	230,035
Accrued expenses and other current liabilities	65,242	82,476
Income taxes payable, current	13,779	9,064
Operating lease liabilities, current	61,107	57,542
Total current liabilities	414,831	386,948
Long-term debt	25,039	25,074
Income taxes payable, noncurrent	43,259	45,878
Operating lease liabilities, noncurrent	183,935	180,848
Other noncurrent liabilities	28,127	9,315
Total liabilities	695,191	648,063
Commitments and contingencies (Note 12)
Stockholders’ equity
Common stock, $0.001 par value; 160,000,000 authorized; 56,001,270 and 55,207,446 shares issued, 55,981,535 and 55,187,711 shares outstanding at September 30, 2020 and December 31, 2019, respectively	56	55
Additional paid-in capital	648,686	607,051
Retained earnings	1,262,341	1,020,590
Treasury stock	(177)	(177)
Accumulated other comprehensive loss	(50,672)	(31,374)
Total stockholders’ equity	1,860,234	1,596,145
Total liabilities and stockholders’ equity	$ 2,555,425	$ 2,244,208

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets
Trade receivables and contract assets allowance	$ 5,371	$ 2,920
Stockholders' equity
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	160,000,000	160,000,000
Common stock, shares issued (in shares)	56,001,270	55,207,446
Common stock, shares outstanding (in shares)	55,981,535	55,187,711

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 652,243	$ 588,103	$ 1,935,985	$ 1,661,023
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	423,388	377,525	1,266,730	1,078,129
Selling, general and administrative expenses	116,530	118,886	355,829	332,434
Depreciation and amortization expense	15,929	11,127	46,095	32,355
Income from operations	96,396	80,565	267,331	218,105
Interest and other income, net	1,672	2,509	5,875	6,775
Foreign exchange gain/(loss)	5,896	(3,105)	3,253	(10,151)
Income before provision for income taxes	103,964	79,969	276,459	214,729
Provision for income taxes	14,532	12,967	34,838	28,196
Net income	89,432	67,002	241,621	186,533
Foreign currency translation adjustments, net of tax	199	(10,114)	(15,878)	(4,551)
Unrealized (loss)/gain on cash-flow hedging instruments, net of tax	(498)	(2,163)	(3,420)	2,474
Comprehensive income	$ 89,133	$ 54,725	$ 222,323	$ 184,456
Net income per share:
Basic (in dollars per share)	$ 1.60	$ 1.22	$ 4.34	$ 3.42
Diluted (in dollars per share)	$ 1.53	$ 1.16	$ 4.14	$ 3.24
Shares used in calculation of net income per share:
Basic (in shares)	55,883,879	54,877,666	55,624,727	54,603,903
Diluted (in shares)	58,616,106	57,844,355	58,341,178	57,567,339

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Restricted stock units	Cumulative effect of adoption	Adjusted balance	Common Stock	Common StockRestricted stock units	Common StockAdjusted balance	Additional Paid-in Capital	Additional Paid-in CapitalRestricted stock units	Additional Paid-in CapitalAdjusted balance	Retained Earnings	Retained EarningsCumulative effect of adoption	Retained EarningsAdjusted balance	Treasury Stock	Treasury StockAdjusted balance	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive LossAdjusted balance
Balance, beginning of period (in shares) at Dec. 31, 2018					54,080,192
Balance, beginning of period at Dec. 31, 2018	$ 1,262,596				$ 54			$ 544,700			$ 759,533					$ (41,514)
Treasury stock, beginning of period (in shares) at Dec. 31, 2018														19,735
Treasury stock, beginning period at Dec. 31, 2018														$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)						242,414
Stock units withheld for employee taxes		$ (13,483)							$ (13,483)
Stock units withheld for employee taxes (in shares)						(81,562)
Proceeds from stock options exercises	11,890							11,890
Proceeds from stock options exercises (in shares)					323,464
Stock-based compensation expense	10,425							10,425
Foreign currency translation adjustments, net of tax	2,943															2,943
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	3,100															3,100
Net income	60,754										60,754
Balance, end of period (in shares) at Mar. 31, 2019					54,564,508
Balance, end of period at Mar. 31, 2019	1,338,225				$ 54			553,532			820,287					(35,471)
Treasury stock, end of period (in shares) at Mar. 31, 2019														19,735
Treasury stock, end of period at Mar. 31, 2019														$ (177)
Balance, beginning of period (in shares) at Dec. 31, 2018					54,080,192
Balance, beginning of period at Dec. 31, 2018	1,262,596				$ 54			544,700			759,533					(41,514)
Treasury stock, beginning of period (in shares) at Dec. 31, 2018														19,735
Treasury stock, beginning period at Dec. 31, 2018														$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Foreign currency translation adjustments, net of tax	(4,551)
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	2,474
Net income	186,533
Balance, end of period (in shares) at Sep. 30, 2019					54,949,098
Balance, end of period at Sep. 30, 2019	1,492,117				$ 55			589,764			946,066					(43,591)
Treasury stock, end of period (in shares) at Sep. 30, 2019														19,735
Treasury stock, end of period at Sep. 30, 2019														$ (177)
Balance, beginning of period (in shares) at Mar. 31, 2019					54,564,508
Balance, beginning of period at Mar. 31, 2019	1,338,225				$ 54			553,532			820,287					(35,471)
Treasury stock, beginning of period (in shares) at Mar. 31, 2019														19,735
Treasury stock, beginning period at Mar. 31, 2019														$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)						11,757
Stock units withheld for employee taxes		(363)							(363)
Stock units withheld for employee taxes (in shares)						(2,084)
Proceeds from stock options exercises	10,584				$ 1			10,583
Proceeds from stock options exercises (in shares)					205,108
Stock-based compensation expense	10,867							10,867
Foreign currency translation adjustments, net of tax	2,620															2,620
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	1,537															1,537
Net income	58,777										58,777
Balance, end of period (in shares) at Jun. 30, 2019					54,779,289
Balance, end of period at Jun. 30, 2019	1,422,247				$ 55			574,619			879,064					(31,314)
Treasury stock, end of period (in shares) at Jun. 30, 2019														19,735
Treasury stock, end of period at Jun. 30, 2019														$ (177)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock issued in connection with acquisitions						18,787
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)						17,216
Stock units withheld for employee taxes		(1,090)							(1,090)
Stock units withheld for employee taxes (in shares)						(5,961)
Proceeds from stock options exercises	6,326							6,326
Proceeds from stock options exercises (in shares)					139,767
Stock-based compensation expense	9,909							9,909
Foreign currency translation adjustments, net of tax	(10,114)															(10,114)
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	(2,163)															(2,163)
Net income	67,002										67,002
Balance, end of period (in shares) at Sep. 30, 2019					54,949,098
Balance, end of period at Sep. 30, 2019	$ 1,492,117				$ 55			589,764			946,066					(43,591)
Treasury stock, end of period (in shares) at Sep. 30, 2019														19,735
Treasury stock, end of period at Sep. 30, 2019														$ (177)
Balance, beginning of period (in shares) at Dec. 31, 2019	55,187,711				55,187,711		55,187,711
Balance, beginning of period at Dec. 31, 2019	$ 1,596,145			$ 1,596,275	$ 55		$ 55	607,051		$ 607,051	1,020,590		$ 1,020,720			(31,374)	$ (31,374)
Balance, beginning of period (ASU 2016-13) at Dec. 31, 2019			$ 130									$ 130
Treasury stock, beginning of period (in shares) at Dec. 31, 2019														19,735	19,735
Treasury stock, beginning period at Dec. 31, 2019														$ (177)	$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)						273,904
Stock units withheld for employee taxes		(15,822)							(15,822)
Stock units withheld for employee taxes (in shares)						(89,990)
Proceeds from stock options exercises	7,141				$ 1			7,140
Proceeds from stock options exercises (in shares)					217,475
Stock-based compensation expense	12,210							12,210
Foreign currency translation adjustments, net of tax	(28,519)															(28,519)
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	(9,368)															(9,368)
Net income	85,565										85,565
Balance, end of period (in shares) at Mar. 31, 2020					55,589,100
Balance, end of period at Mar. 31, 2020	$ 1,647,482				$ 56			610,579			1,106,285					(69,261)
Treasury stock, end of period (in shares) at Mar. 31, 2020														19,735
Treasury stock, end of period at Mar. 31, 2020														$ (177)
Balance, beginning of period (in shares) at Dec. 31, 2019	55,187,711				55,187,711		55,187,711
Balance, beginning of period at Dec. 31, 2019	$ 1,596,145			$ 1,596,275	$ 55		$ 55	607,051		$ 607,051	1,020,590		$ 1,020,720			(31,374)	$ (31,374)
Balance, beginning of period (ASU 2016-13) at Dec. 31, 2019			$ 130									$ 130
Treasury stock, beginning of period (in shares) at Dec. 31, 2019														19,735	19,735
Treasury stock, beginning period at Dec. 31, 2019														$ (177)	$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Foreign currency translation adjustments, net of tax	(15,878)
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	(3,420)
Net income	$ 241,621
Balance, end of period (in shares) at Sep. 30, 2020	55,981,535				55,981,535
Balance, end of period at Sep. 30, 2020	$ 1,860,234				$ 56			648,686			1,262,341					(50,672)
Treasury stock, end of period (in shares) at Sep. 30, 2020														19,735
Treasury stock, end of period at Sep. 30, 2020														$ (177)
Balance, beginning of period (in shares) at Mar. 31, 2020					55,589,100
Balance, beginning of period at Mar. 31, 2020	1,647,482				$ 56			610,579			1,106,285					(69,261)
Treasury stock, beginning of period (in shares) at Mar. 31, 2020														19,735
Treasury stock, beginning period at Mar. 31, 2020														$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)						18,649
Stock units withheld for employee taxes		(1,169)							(1,169)
Stock units withheld for employee taxes (in shares)						(5,522)
Proceeds from stock options exercises	10,116							10,116
Proceeds from stock options exercises (in shares)					223,724
Stock-based compensation expense	11,153							11,153
Foreign currency translation adjustments, net of tax	12,442															12,442
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	6,446															6,446
Net income	66,624										66,624
Balance, end of period (in shares) at Jun. 30, 2020					55,825,951
Balance, end of period at Jun. 30, 2020	1,753,094				$ 56			630,679			1,172,909					(50,373)
Treasury stock, end of period (in shares) at Jun. 30, 2020														19,735
Treasury stock, end of period at Jun. 30, 2020														$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)						4,696
Stock units withheld for employee taxes		$ (294)							$ (294)
Stock units withheld for employee taxes (in shares)						(1,015)
Proceeds from stock options exercises	5,735							5,735
Proceeds from stock options exercises (in shares)					151,903
Stock-based compensation expense	12,566							12,566
Foreign currency translation adjustments, net of tax	199															199
Change in unrealized gains and losses on cash flow hedging instruments, net of tax	(498)															(498)
Net income	$ 89,432										89,432
Balance, end of period (in shares) at Sep. 30, 2020	55,981,535				55,981,535
Balance, end of period at Sep. 30, 2020	$ 1,860,234				$ 56			$ 648,686			$ 1,262,341					$ (50,672)
Treasury stock, end of period (in shares) at Sep. 30, 2020														19,735
Treasury stock, end of period at Sep. 30, 2020														$ (177)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 241,621	$ 186,533
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	46,095	32,355
Operating lease right-of-use assets amortization expense	50,467	40,203
Bad debt expense	2,794	133
Deferred taxes	(4,546)	(3,105)
Stock-based compensation expense	54,794	53,024
Other	3,225	7,522
Changes in assets and liabilities:
Trade receivables and contract assets	3,477	(77,833)
Prepaid and other assets	4,261	237
Accounts payable	1,836	(1,844)
Accrued expenses and other liabilities	30,787	(11,230)
Operating lease liabilities	(47,023)	(39,230)
Income taxes payable	(2,813)	(23,899)
Net cash provided by operating activities	384,975	162,866
Cash flows from investing activities:
Purchases of property and equipment	(50,311)	(52,295)
Purchases of short-term investments	(60,000)	0
Acquisition of business, net of cash acquired (Note 2)	(18,888)	(28,655)
Purchases of non-marketable securities	(20,500)	(5,000)
Other investing activities, net	452	(1,632)
Net cash used in investing activities	(149,247)	(87,582)
Cash flows from financing activities:
Proceeds from stock option exercises	23,027	28,798
Payments of withholding taxes related to net share settlements of restricted stock units	(16,213)	(14,521)
Payment of contingent consideration for previously acquired business	(7,869)	(1,104)
Other financing activities, net	(28)	(26)
Net cash (used in)/provided by financing activities	(1,083)	13,147
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(10,110)	(5,753)
Net increase in cash, cash equivalents and restricted cash	224,535	82,678
Cash, cash equivalents and restricted cash, beginning of period	937,688	771,711
Cash, cash equivalents and restricted cash, end of period	$ 1,162,223	$ 854,389

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOW (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Cash and cash equivalents	$ 1,161,065	$ 936,552
Total restricted cash	1,158	1,136
Total cash, cash equivalents, restricted cash and restricted cash equivalents	1,162,223	937,688
Other noncurrent assets
Restricted cash	$ 1,158	$ 1,136

BUSINESS AND SUMMARY OF SIGNIFI

BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES EPAM Systems, Inc. (the “Company” or “EPAM”) is a leading global provider of digital platform engineering and software development services to customers located around the world, primarily in North America, Europe, Asia and Australia. The Company’s industry expertise includes financial services, travel and consumer, software and hi-tech, business information and media, life sciences and healthcare, as well as other emerging industries. The Company is incorporated in Delaware with headquarters in Newtown, Pennsylvania. Basis of Presentation — The accompanying unaudited condensed consolidated financial statements of EPAM have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP” or “U.S. GAAP”) and Article 10 of Regulation S-X under the Securities Exchange Act of 1934, as amended. The unaudited condensed consolidated financial statements include the financial statements of EPAM Systems, Inc. and its subsidiaries with all intercompany balances and transactions eliminated. These unaudited condensed consolidated financial statements and accompanying notes should be read in conjunction with the Company’s audited consolidated financial statements and the notes thereto for the year ended December 31, 2019 included in its Annual Report on Form 10-K. The preparation of these condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in these condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates, and such differences may be material to the condensed consolidated financial statements. Operating results for the interim periods are not necessarily indicative of results that may be expected to occur for the entire year. In management’s opinion, all adjustments considered necessary for a fair presentation of the accompanying unaudited condensed consolidated financial statements have been included, and all adjustments are of a normal and recurring nature. As previously disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, certain amounts recorded in the prior-period consolidated statement of cash flows presented have been reclassified to conform to the current-period financial statement presentation. These reclassifications had no effect on previously reported results of operations. Adoption of New Accounting Standards Unless otherwise discussed below, the adoption of new accounting standards did not have a material impact on the Company’s consolidated financial position, results of operations, changes in stockholders’ equity and cash flows. Measurement of Credit Losses on Financial Instruments — In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this update changed how companies measure and recognize credit impairment for many financial assets. The new credit loss model requires companies to immediately recognize an estimate of credit losses expected to occur over the remaining life of the financial assets (including trade receivables) that are in the scope of the update. The update also made amendments to the current impairment model for held-to-maturity and available-for-sale debt securities and certain guarantees. The Company adopted Topic 326, effective January 1, 2020, using a modified-retrospective approach through a cumulative effect adjustment to retained earnings as of the beginning of the period of adoption. As a result of the adoption of Topic 326, the Company recorded an immaterial reduction to its allowance for doubtful accounts for trade receivables and contract assets . Pending Accounting Standards From time to time, new accounting pronouncements are issued by the FASB or other standards-setting bodies that the Company will adopt according to the various timetables the FASB specifies. The Company believes the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position, results of operations and cash flows upon adoption.

ACQUISITION

ACQUISITION	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
ACQUISITION	ACQUISITIONS 2020 Acquisitions — During the nine months ended September 30, 2020, the Company completed two acquisitions with an aggregate purchase price of $22,526 including contingent consideration with an acquisition-date fair value of $5,292. The Company committed to making contingent consideration payments with a maximum amount payable of $18,582 subject to attainment of specified performance targets in the first and second calendar years after the respective acquisition dates. These acquisitions increased EPAM’s software and service capabilities and expanded EPAM’s offerings in financial services as well as added $7,280 of intangible assets, consisting mainly of customer relationships. Revenues generated by these acquisitions totaled $1,245 and $3,478 during the three and nine months ended September 30, 2020, respectively. Pro forma results of operations have not been presented because the effect of these acquisitions on the Company’s condensed consolidated financial statements was not material individually or in aggregate. test IO — During the second quarter of 2020, the Company finalized the fair value of the assets acquired and liabilities assumed in the acquisition of test IO. During 2020, the Company recorded insignificant purchase price adjustments to various accounts with corresponding net decreases to goodwill of $226. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed as of the date of acquisition as updated for any changes as of June 30, 2020 for test IO: test IO Cash and cash equivalents $ 663 Trade receivables and contract assets 621 Prepaid and other current assets 150 Goodwill 11,926 Intangible assets 6,219 Property and equipment and other noncurrent assets 305 Total assets acquired $ 19,884 Accounts payable, accrued expenses and other current liabilities $ 993 Other noncurrent liabilities 1,568 Total liabilities assumed $ 2,561 Net assets acquired $ 17,323

GOODWILL

GOODWILL	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	GOODWILL Goodwill by reportable segment was as follows: North America Europe Russia Total Balance as of January 1, 2020 $ 113,426 $ 80,873 $ 744 $ 195,043 test IO purchase accounting adjustment 863 (1,089) — (226) Other 2019 acquisitions purchase accounting adjustments 219 71 21 311 2020 Acquisitions 6,236 6,822 — 13,058 Effect of net foreign currency exchange rate changes 98 (457) (63) (422) Balance as of September 30, 2020 $ 120,842 $ 86,220 $ 702 $ 207,764

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS The Company carries certain assets and liabilities at fair value on a recurring basis on its consolidated balance sheets. The following tables present the fair values of the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2020 and December 31, 2019: As of September 30, 2020 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 936 $ — $ 936 $ — Total assets measured at fair value on a recurring basis $ 936 $ — $ 936 $ — Foreign exchange derivative liabilities $ 3,689 $ — $ 3,689 $ — Contingent consideration 5,913 — — 5,913 Total liabilities measured at fair value on a recurring basis $ 9,602 $ — $ 3,689 $ 5,913 As of December 31, 2019 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 1,910 $ — $ 1,910 $ — Total assets measured at fair value on a recurring basis $ 1,910 $ — $ 1,910 $ — Foreign exchange derivative liabilities $ 243 $ — $ 243 $ — Contingent consideration 10,495 — — 10,495 Total liabilities measured at fair value on a recurring basis $ 10,738 $ — $ 243 $ 10,495 The foreign exchange derivatives are valued using pricing models and discounted cash flow methodologies based on observable foreign exchange data at the measurement date. See Note 5 “Derivative Financial Instruments” in the condensed consolidated interim financial statements for additional information regarding derivative financial instruments. The fair value of the contingent consideration was determined using a probability-weighted expected return method and is based on 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. Although there is significant judgment involved, the Company believes its estimates and assumptions are reasonable. In determining fair value, the Company considered a variety of factors, including future performance of the acquired businesses using financial projections developed by the Company and market risk assumptions that were derived for revenue growth and earnings before interest and taxes. The Company estimated future payments using the earnout formula and performance targets specified in the purchase agreements and adjusted those estimates to reflect the probability of their achievement. Those weighted-average estimated future payments were then discounted to present value using a rate based on the weighted-average cost of capital of guideline companies. The discount rates used to determine the fair value of contingent consideration for the 2020 Acquisitions ranged from a minimum of 15.5% to a maximum of 17.5%. Changes in financial projections, market risk assumptions, discount rates or probability assumptions related to achieving the various earnout criteria would result in a change in the fair value of the recorded contingent liabilities. Such changes, if any, are recorded within Interest and other income, net in the Company’s condensed consolidated statement of income and comprehensive income. A reconciliation of the beginning and ending balances of Level 3 acquisition-related contingent consideration using significant unobservable inputs for the nine months ended September 30, 2020 is as follows: Amount Contingent consideration liabilities as of January 1, 2020 $ 10,495 Payment of contingent consideration for previously acquired business (7,869) Acquisition date fair value of contingent consideration — 2020 Acquisitions (Note 2) 5,292 Changes in fair value of contingent consideration included in Interest and other income, net (1,480) Effect of net foreign currency exchange rate changes (525) Contingent consideration liabilities as of September 30, 2020 $ 5,913 Financial Assets and Liabilities Not Measured at Fair Value on a Recurring Basis Estimates of fair value of financial instruments not carried at fair value on a recurring basis on the Company’s consolidated balance sheets are generally subjective in nature, and are determined as of a specific point in time based on the characteristics of the financial instruments and relevant market information. The generally short maturities of certain assets and liabilities result in a number of assets and liabilities for which fair value equals or closely approximates the amount recorded on the Company’s condensed consolidated balance sheets. The following tables present the estimated fair values of the Company’s financial assets and liabilities not measured at fair value on a recurring basis as of the dates indicated: Fair Value Hierarchy Balance Estimated Fair Value Level 1 Level 2 Level 3 September 30, 2020 Financial Assets: Cash equivalents: Money market funds $ 171,903 $ 171,903 $ 171,903 $ — $ — Total cash equivalents $ 171,903 $ 171,903 $ 171,903 $ — $ — Restricted cash $ 1,158 $ 1,158 $ 1,158 $ — $ — Time deposits $ 60,089 $ 60,089 $ — $ 60,089 $ — Employee loans $ 1,168 $ 1,168 $ — $ — $ 1,168 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,006 $ 25,006 $ — $ 25,006 $ — Fair Value Hierarchy Balance Estimated Fair Value Level 1 Level 2 Level 3 December 31, 2019 Financial Assets: Cash equivalents: Money market funds $ 407,817 $ 407,817 $ 407,817 $ — $ — Time deposits 10,002 10,002 — 10,002 — Total cash equivalents $ 417,819 $ 417,819 $ 407,817 $ 10,002 $ — Restricted cash $ 1,136 $ 1,136 $ 1,136 $ — $ — Employee loans $ 2,434 $ 2,434 $ — $ — $ 2,434 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,017 $ 25,017 $ — $ 25,017 $ — Non-Marketable Securities Without Readily Determinable Fair Values The Company holds investments in equity securities that do not have readily determinable fair values. These investments are recorded at cost and are remeasured to fair value based on certain observable price changes or impairment events as they occur. The carrying amount of these investments was $25,000 and $5,750 as of September 30, 2020 and December 31, 2019, respectively and is classified as Other noncurrent assets in the Company’s condensed consolidated balance sheets.

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	DERIVATIVE FINANCIAL INSTRUMENTS In the normal course of business, the Company uses derivative financial instruments to manage the risk of fluctuations in foreign currency exchange rates. The Company has a hedging program whereby it enters into a series of foreign exchange forward contracts with durations of twelve months or less that are designated as cash flow hedges of forecasted Russian ruble, Polish zloty and Indian rupee transactions. As of September 30, 2020, all of the Company’s foreign exchange forward contracts were designated as hedges and there is no financial collateral (including cash collateral) required to be posted by the Company related to the foreign exchange forward contracts. The fair value of derivative instruments on the Company’s consolidated balance sheets as of September 30, 2020 and December 31, 2019 were as follows: As of September 30, 2020 As of December 31, 2019 Balance Sheet Classification Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives Foreign exchange forward contracts - Prepaid expenses and other current assets $ 936 $ 1,910 Accrued expenses and other current liabilities $ 3,689 $ 243 The Company records changes in the fair value of its cash flow hedges in accumulated other comprehensive loss in the condensed consolidated balance sheets until the forecasted transaction occurs. When the forecasted transaction occurs, the Company reclassifies the related gain or loss on the cash flow hedge to cost of revenues (exclusive of depreciation and amortization). In the event the underlying forecasted transaction does not occur, or it becomes probable that it will not occur, the Company reclassifies the gain or loss on the related cash flow hedge into income. If the Company does not elect hedge accounting, or the contract does not qualify for hedge accounting treatment, the changes in fair value from period to period are recorded in income. The changes in the fair value of foreign currency derivative instruments in our unaudited condensed consolidated statements of income and comprehensive income for the three and nine months ended September 30, 2020 and 2019 were as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Foreign exchange forward contracts - Designated as hedging instruments: Net (loss)/gain in fair value recognized in accumulated other comprehensive loss $ (650) $ (2,791) $ (4,420) $ 3,192 Net (loss)/gain reclassified from accumulated other comprehensive loss into cost of revenues (exclusive of depreciation and amortization) $ (1,094) $ 848 $ (3,605) $ 738

LEASES

LEASES	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
LEASES	LEASESThe Company leases office space, corporate apartments, office equipment, and vehicles. Many of the Company’s leases contain variable payments including changes in base rent and charges for common area maintenance or other miscellaneous expenses. Due to this variability, the cash flows associated with these variable payments are not included in the minimum lease payments used in determining the right-of-use assets and associated lease liabilities and are recognized in the period in which the obligation for such payments is incurred. The Company’s leases have remaining lease terms ranging from 0.1 years to 10.6 years. Certain lease agreements, mainly for office space, include options to extend or terminate the lease before the expiration date. The Company considers such options when determining the lease term when it is reasonably certain that the Company will exercise that option. The Company leases and subleases a portion of its office space to third parties. Lease income and sublease income were immaterial for the three and nine months ended September 30, 2020 and 2019. During the three and nine months ended September 30, 2020 and 2019, the components of lease expense were as follows: Three Months Ended Nine Months Ended Income Statement Classification 2020 2019 2020 2019 Operating lease cost Selling, general and administrative expenses $ 18,437 $ 16,210 $ 56,151 $ 45,125 Variable lease cost Selling, general and administrative expenses 1,442 2,439 4,656 6,535 Short-term lease cost Selling, general and administrative expenses 180 1,085 989 2,989 Total lease cost $ 20,059 $ 19,734 $ 61,796 $ 54,649 Supplemental cash flow information related to leases for the three and nine months ended September 30, 2020 and 2019 was as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 17,952 $ 14,709 $ 51,324 $ 43,510 Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 2,277 $ 14,251 $ 45,205 $ 67,798 Non-cash net increase due to lease modifications: Operating lease right-of-use assets $ 11,726 $ 3,233 $ 7,744 $ 6,383 Operating lease liabilities $ 11,708 $ 3,199 $ 7,719 $ 6,451 Weighted average remaining lease term and discount rate as of September 30, 2020 and 2019 were as follows: As of September 30, 2020 As of September 30, 2019 Weighted average remaining lease term, in years: Operating leases 5.9 5.9 Weighted average discount rate: Operating leases 3.1 % 3.8 % As of September 30, 2020, operating lease liabilities will mature as follows: Year ending December 31, Lease Payments 2020 (excluding nine months ended September 30, 2020) $ 18,334 2021 63,652 2022 48,523 2023 35,343 2024 30,360 Thereafter 71,115 Total lease payments 267,327 Less: imputed interest (22,285) Total $ 245,042 The Company had committed to payments of $5,724 related to operating lease agreements that had not yet commenced as of September 30, 2020. These operating leases will commence on various dates during 2020 with lease terms ranging from 1.0 to 5.0 years. The Company did not have any material finance lease agreements that had not yet commenced.

LONG-TERM DEBT

LONG-TERM DEBT	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT Revolving Line of Credit — On May 24, 2017, the Company entered into an unsecured credit facility (the “2017 Credit Facility”), as may be amended from time to time, with PNC Bank, National Association; PNC Capital Markets LLC; Citibank N.A.; Wells Fargo Bank, National Association; Fifth Third Bank and Santander Bank, N.A. (collectively the “Lenders”). The 2017 Credit Facility provides for a borrowing capacity of $300,000, with potential to increase the borrowing capacity up to $400,000 if certain conditions are met. The 2017 Credit Facility matures on May 24, 2022. Borrowings under the 2017 Credit Facility may be denominated in U.S. dollars or up to a maximum of $100,000 equivalent in British pounds sterling, Canadian dollars, euros or Swiss francs and other currencies as may be approved by the administrative agent and the Lenders. Borrowings under the 2017 Credit Facility bear interest at either a base rate or Euro-rate plus a margin based on the Company’s leverage ratio. The base rate is equal to the highest of (a) the Overnight Bank Funding Rate, plus 0.5%, (b) the Prime Rate, and (c) the Daily LIBOR Rate, plus 1.0%. As of September 30, 2020, the Company’s outstanding borrowings are subject to a LIBOR-based interest rate which resets regularly at issuance, based on lending terms. The 2017 Credit Facility includes customary business and financial covenants that may restrict the Company’s ability to make or pay dividends (other than certain intercompany dividends) if a potential or an actual event of default has occurred or would be triggered. As of September 30, 2020, the Company was in compliance with all covenants contained in the 2017 Credit Facility. The following table presents the outstanding debt and borrowing capacity of the Company under the 2017 Credit Facility: As of As of Outstanding debt $ 25,000 $ 25,000 Interest rate 1.2 % 2.8 % Irrevocable standby letters of credit $ — $ 303 Available borrowing capacity $ 275,000 $ 274,697 Current maximum borrowing capacity $ 300,000 $ 300,000

REVENUES

REVENUES	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
REVENUES	REVENUES Disaggregation of Revenues The following tables present the disaggregation of the Company’s revenues by customer location, including a reconciliation of the disaggregated revenues with the reportable segments (Note 13 “Segment Information”) for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 378,493 $ 10,853 $ 630 $ 389,976 Europe 11,278 203,255 — 214,533 CIS 1,433 16 28,590 30,039 APAC 401 17,294 — 17,695 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 1,126,970 $ 32,107 $ 2,665 $ 1,161,742 Europe 32,805 615,843 6 648,654 CIS 6,223 32 70,722 76,977 APAC 1,538 47,074 — 48,612 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 349,875 $ 8,484 $ 42 $ 358,401 Europe 6,756 182,533 23 189,312 CIS 2,349 53 24,099 26,501 APAC 7 13,882 — 13,889 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 976,841 $ 32,926 $ 74 $ 1,009,841 Europe 16,722 523,180 263 540,165 CIS 6,093 66 63,607 69,766 APAC 1,045 40,206 — 41,251 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 The following tables present the disaggregation of the Company’s revenues by industry vertical, including a reconciliation of the disaggregated revenues with the reportable segments (Note 13 “Segment Information”) for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 84,384 $ 55,228 $ 402 $ 140,014 Financial Services 48,415 68,419 19,881 136,715 Software & Hi-Tech 100,847 17,492 515 118,854 Travel & Consumer 54,590 51,449 4,135 110,174 Life Sciences & Healthcare 66,071 7,963 169 74,203 Emerging Verticals 37,298 30,867 4,118 72,283 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 246,085 $ 171,712 $ 1,201 $ 418,998 Financial Services 143,970 202,668 49,695 396,333 Software & Hi-Tech 303,385 53,803 3,000 360,188 Travel & Consumer 161,507 163,769 11,698 336,974 Life Sciences & Healthcare 189,458 22,651 217 212,326 Emerging Verticals 123,131 80,453 7,582 211,166 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 65,153 $ 40,624 $ 22 $ 105,799 Financial Services 50,510 61,067 18,760 130,337 Software & Hi-Tech 90,880 16,952 552 108,384 Travel & Consumer 51,476 57,735 3,171 112,382 Life Sciences & Healthcare 60,049 6,713 7 66,769 Emerging Verticals 40,919 21,861 1,652 64,432 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 189,854 $ 108,846 $ 266 $ 298,966 Financial Services 132,421 181,781 49,801 364,003 Software & Hi-Tech 255,601 56,762 1,470 313,833 Travel & Consumer 146,654 169,112 8,056 323,822 Life Sciences & Healthcare 164,492 16,176 73 180,741 Emerging Verticals 111,679 63,701 4,278 179,658 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 The following tables present the disaggregation of the Company’s revenues by contract type including a reconciliation of the disaggregated revenues with the Company’s reportable segments (Note 13 “Segment Information”) for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 348,570 $ 196,719 $ 13,844 $ 559,133 Fixed-price 41,050 34,057 15,314 90,421 Licensing 1,717 242 53 2,012 Other revenues 268 400 9 677 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 1,054,548 $ 579,212 $ 41,412 $ 1,675,172 Fixed-price 106,760 111,565 30,394 248,719 Licensing 5,445 949 1,520 7,914 Other revenues 783 3,330 67 4,180 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 322,573 $ 171,261 $ 13,815 $ 507,649 Fixed-price 35,273 33,093 10,304 78,670 Licensing 883 149 9 1,041 Other revenues 258 449 36 743 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 907,624 $ 507,055 $ 37,134 $ 1,451,813 Fixed-price 89,694 87,543 26,534 203,771 Licensing 2,343 689 211 3,243 Other revenues 1,040 1,091 65 2,196 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 Timing of Revenue Recognition The following tables present the timing of revenue recognition for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 390,295 $ 231,281 $ 29,174 $ 650,750 Transferred at a point of time 1,310 137 46 1,493 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 1,163,678 $ 694,525 $ 71,882 $ 1,930,085 Transferred at a point of time 3,858 531 1,511 5,900 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 358,426 $ 204,833 $ 24,110 $ 587,369 Transferred at a point of time 561 119 54 734 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 999,530 $ 596,106 $ 63,890 $ 1,659,526 Transferred at a point of time 1,171 272 54 1,497 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 During the three and nine months ended September 30, 2020 the Company recognized $9,105 and $4,719 of revenues, respectively, from performance obligations satisfied in previous periods compared to $4,915 and $7,039 during the three and nine months ended September 30, 2019, respectively. The following table includes the estimated revenues expected to be recognized in the future related to performance obligations that are partially or fully unsatisfied as of September 30, 2020. The Company applies a practical expedient and does not disclose the value of unsatisfied performance obligations for contracts that (i) have an original expected duration of one year or less and (ii) contracts for which it recognizes revenues at the amount to which it has the right to invoice for services provided: Less than 1 year 1 Year 2 Years 3 Years Total Contract Type Fixed-price $ 19,644 $ 288 $ — $ — $ 19,932 The Company applies a practical expedient and does not disclose the amount of the transaction price allocated to the remaining performance obligations nor provide an explanation of when the Company expects to recognize that amount as revenue for certain variable consideration. Contract Balances The following table provides information on the classification of contract assets and liabilities in the condensed consolidated balance sheets: As of As of Contract assets included in Trade receivables and contract assets $ 21,548 $ 14,320 Contract liabilities included in Accrued expenses and other current liabilities $ 12,415 $ 9,132 Contract assets have increased from December 31, 2019 primarily due to contracts where the Company’s right to bill is contingent upon achievement of contractual milestones. Contract liabilities comprise amounts collected from the Company’s customers for revenues not yet earned. Such amounts are anticipated to be recorded as revenues when services are performed in subsequent periods. Contract liabilities have not materially changed from December 31, 2019. During the three and nine months ended September 30, 2020, the Company recognized $439 and $8,301 of revenues, respectively, that were included in Accrued expenses and other current liabilities at December 31, 2019. During the three and nine months ended September 30, 2019, the Company recognized $140 and $3,801 of revenues, respectively, that were included in Accrued expenses and other current liabilities at December 31, 2018.

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION The following table summarizes the components of stock-based compensation expense recognized in the Company’s condensed consolidated statements of income and comprehensive income for the periods indicated: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Cost of revenues (exclusive of depreciation and amortization) $ 10,854 $ 7,580 $ 23,796 $ 27,841 Selling, general and administrative expenses 12,620 7,891 30,998 25,183 Total $ 23,474 $ 15,471 $ 54,794 $ 53,024 Stock Options Stock option activity under the Company’s plans is set forth below: Number of Weighted Average Aggregate Weighted Average Options outstanding at January 1, 2020 3,322,930 $ 50.85 Options granted 147,351 $ 176.21 Options modified (198) $ 73.27 Options exercised (592,904) $ 38.76 Options forfeited/cancelled (9,137) $ 117.40 Options outstanding at September 30, 2020 2,868,042 $ 59.58 $ 756,305 4.5 Options vested and exercisable at September 30, 2020 2,489,928 $ 46.31 $ 689,630 3.9 Options expected to vest at September 30, 2020 353,203 $ 145.98 $ 62,624 8.4 As of September 30, 2020, $15,575 of total remaining unrecognized stock-based compensation cost related to unvested stock options, net of estimated forfeitures, is expected to be recognized over the weighted-average remaining requisite service period of 2.8 years. Restricted Stock and Restricted Stock Units Service-Based Awards The table below summarizes activity related to the Company’s equity-classified and liability-classified service-based awards for the nine months ended September 30, 2020: Equity-Classified Restricted Stock Equity-Classified Equity-Settled Restricted Stock Units Liability-Classified Cash-Settled Restricted Stock Units Number of Shares Weighted Average Grant Date Number of Shares Weighted Average Grant Date Number of Shares Weighted Average Grant Date Unvested service-based awards outstanding at January 1, 2020 9,791 $ 162.96 758,785 $ 122.48 242,288 $ 105.40 Awards granted — $ — 252,376 $ 180.39 59,770 $ 180.37 Awards modified — $ — (1,237) $ 122.55 — $ — Awards vested (397) $ 63.10 (298,331) $ 107.31 (121,399) $ 91.22 Awards forfeited/cancelled — $ — (35,446) $ 140.33 (4,106) $ 112.58 Unvested service-based awards outstanding at September 30, 2020 9,394 $ 167.18 676,147 $ 149.85 176,553 $ 140.36 As of September 30, 2020, $897 of total remaining unrecognized stock-based compensation cost related to service-based equity-classified restricted stock is expected to be recognized over the weighted-average remaining requisite service period of 1.9 years. As of September 30, 2020, $73,991 of total remaining unrecognized stock-based compensation cost related to service-based equity-classified restricted stock units (“RSUs”), net of estimated forfeitures, is expected to be recognized over the weighted-average remaining requisite service period of 2.6 years. During the nine months ended September 30, 2020, 19,201 equity-classified RSUs were granted in connection with 2020 acquisitions of businesses. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. During the first quarter of 2020, in connection with a 2019 acquisition of a business, the Company formally issued 5,793 equity-classified RSUs. As of September 30, 2020, $34,399 of total remaining unrecognized stock-based compensation cost related to service-based liability-classified cash-settled RSUs, net of estimated forfeitures, is expected to be recognized over the weighted-average remaining requisite service period of 2.4 years. During the nine months ended September 30, 2020, 9,736 liability-classified cash-settled RSUs were granted in connection with 2020 acquisitions of businesses. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. The liability associated with the service-based liability-classified RSUs as of September 30, 2020 and December 31, 2019, was $18,577 and $21,902, respectively, and was classified as Accrued compensation and benefits expenses in the condensed consolidated balance sheets. Performance-Based Awards The table below summarizes activity related to the Company’s equity-classified performance-based awards for the nine months ended September 30, 2020: Equity-Classified Equity-Settled Restricted Stock Equity-Classified Equity-Settled Restricted Stock Units Number of Shares Weighted Average Grant Date Number of Shares Weighted Average Grant Date Unvested performance-based awards outstanding at January 1, 2020 9,393 $ 165.87 — $ — Awards granted — $ — 31,354 $ 210.44 Unvested performance-based awards outstanding at September 30, 2020 9,393 $ 165.87 31,354 $ 210.44 As of September 30, 2020, $1,137 of total remaining unrecognized stock-based compensation cost related to performance-based restricted stock is expected to be recognized over the weighted-average remaining requisite service period of 2.9 years. During the nine months ended September 30, 2020, in connection with a 2019 acquisition of a business, the Company formally issued 24,836 performance-based equity-classified RSUs. During the nine months ended September 30, 2020, 6,518 performance-based equity-classified RSUs were granted in connection with 2020 acquisitions of businesses. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. As of September 30, 2020, $4,096 of total remaining unrecognized stock-based compensation cost related to performance-based equity-classified RSUs is expected to be recognized over the weighted-average remaining requisite service period of 3.0 years.

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES In determining its interim provision for income taxes, the Company uses an estimated annual effective tax rate, which is based on expected annual profit before tax, statutory tax rates and tax planning opportunities available in the various jurisdictions in which the Company operates. Certain significant or unusual items are separately recognized in the quarter in which they occur and can be a source of variability in the effective tax rates from quarter to quarter. The Company’s worldwide effective tax rates for the three months ended September 30, 2020 and 2019 were 14.0% and 16.2%, respectively, and 12.6% and 13.1% during the nine months ended September 30, 2020 and 2019, respectively.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Basic earnings per share is computed by dividing net income available to common shareholders by the weighted-average number of shares of common stock outstanding during the period. For purposes of computing basic earnings per share, any nonvested shares of restricted stock that have been issued by the Company and are contingently returnable to the Company are excluded from the weighted-average number of shares of common stock outstanding during the period. Diluted earnings per share is computed by dividing net income available to common shareholders by the weighted-average number of shares of common stock outstanding during the period increased to include the number of additional shares of common stock that would have been outstanding if the potentially dilutive securities had been issued. Potentially dilutive securities include outstanding stock options, unvested restricted stock and unvested equity-settled RSUs. The dilutive effect of potentially dilutive securities is reflected in diluted earnings per share by application of the treasury stock method. The following table sets forth the computation of basic and diluted earnings per share of common stock as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Numerator for basic and diluted earnings per share: Net income $ 89,432 $ 67,002 $ 241,621 $ 186,533 Numerator for basic and diluted earnings per share $ 89,432 $ 67,002 $ 241,621 $ 186,533 Denominator: Weighted average common shares for basic earnings per share 55,883,879 54,877,666 55,624,727 54,603,903 Net effect of dilutive stock options, restricted stock units and restricted stock awards 2,732,227 2,966,689 2,716,451 2,963,436 Weighted average common shares for diluted earnings per share 58,616,106 57,844,355 58,341,178 57,567,339 Net income per share: Basic $ 1.60 $ 1.22 $ 4.34 $ 3.42 Diluted $ 1.53 $ 1.16 $ 4.14 $ 3.24 The number of shares underlying equity-based awards that were excluded from the calculation of diluted earnings per share as their effect would be anti-dilutive was 2,627 and 40,276 during the three and nine months ended September 30, 2020, respectively. The number of shares underlying equity-based awards that were excluded from the calculation of diluted earnings per share as their effect would be anti-dilutive was 143,617 and 112,757 during the three and nine months ended September 30, 2019, respectively.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES 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, infringement of third party intellectual property rights, data privacy violations, and certain tortious conduct in the course of providing services. 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 would have a material effect on the condensed consolidated financial statements of the Company. Litigation — From time to time, the Company is involved in litigation, claims or other contingencies arising in the ordinary course of business. The Company accrues a liability when a loss is considered probable and the amount can be reasonably estimated. When a material loss contingency is reasonably possible but not probable, the Company does not record a liability, but instead discloses the nature and the amount of the claim, and an estimate of the loss or range of loss, if such an estimate can be made. Legal fees are expensed as incurred. In the opinion of management, the outcome of any existing claims and legal or regulatory proceedings, if decided adversely, is not expected to have a material effect on the Company’s business, financial condition, results of operations or cash flows. Building Acquisition Commitments — During the year ended December 31, 2019, the Company entered into an agreement to purchase office space in Ukraine intended to support the global delivery center in that country. The agreement is subject to completion of construction and other ordinary closing conditions. As of September 30, 2020, the Company has committed to making future payments totaling approximately $36,900 including VAT to the sellers upon transfer of the building.

SEGMENTS INFORMATION

SEGMENTS INFORMATION	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
SEGMENT INFORMATION	SEGMENT INFORMATION The Company determines its business segments and reports segment information in accordance with how the Company’s chief operating decision maker (“CODM”) organizes the segments to evaluate performance, allocate resources and make business decisions. Segment results are based on the segment’s revenues and operating profit, where segment operating profit is defined as income from operations before unallocated costs. 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 corporate expenses are not allocated to specific segments as these expenses are not controllable at the segment level. Such expenses include certain types of professional fees, non-corporate taxes, compensation to non-employee directors and certain other general and administrative expenses, including compensation of specific groups of non-production employees. In addition, the Company does not allocate amortization of intangible assets acquired through business combinations, goodwill and other asset impairment charges, stock-based compensation expenses, acquisition-related costs and certain other one-time charges. These unallocated amounts are combined with total segment operating profit to arrive at consolidated income from operations as reported below in the reconciliation of segment operating profit to consolidated income before provision for income taxes. Additionally, management has determined that it is not practical to allocate identifiable assets by segment since such assets are used interchangeably among the segments. The Company manages its business primarily based on the managerial responsibility for its client base and market. As managerial responsibility for a particular customer relationship generally correlates with the customer’s geographic location, there is a high degree of similarity between customer locations and the geographic boundaries of the Company’s reportable segments. In some cases, managerial responsibility for a particular customer is assigned to a management team in another region and is usually based on the strength of the relationship between customer executives and particular members of EPAM’s senior management team. In such cases, the customer’s activity would be reported through the management team’s reportable segment. During the fourth quarter of 2019, the Company changed its management reporting of segment revenue to exclude other income. Prior year amounts presented below have been changed to conform to the new presentation. Revenues from external customers and operating profit/(loss), before unallocated expenses, by reportable segment for the three and nine months ended September 30, 2020 and 2019, were as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Segment revenues: North America $ 391,605 $ 358,987 $ 1,167,536 $ 1,000,701 Europe 231,418 204,952 695,056 596,378 Russia 29,220 24,164 73,393 63,944 Total segment revenues $ 652,243 $ 588,103 $ 1,935,985 $ 1,661,023 Segment operating profit/(loss): North America $ 87,272 $ 79,310 $ 248,951 $ 213,114 Europe 43,018 27,550 109,223 87,014 Russia 2,958 5,524 (2,168) 11,765 Total segment operating profit $ 133,248 $ 112,384 $ 356,006 $ 311,893 Intersegment transactions were excluded from the above on the basis that they are neither included in the measure of a segment’s profit and loss results, nor considered by the CODM during the review of segment results. There were no customers that accounted for more than 10% of total segment revenues during the three and nine months ended September 30, 2020 and 2019. Reconciliation of segment operating profit to consolidated income before provision for income taxes is presented below: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Total segment operating profit: $ 133,248 $ 112,384 $ 356,006 $ 311,893 Unallocated amounts: Stock-based compensation expense (23,474) (15,471) (54,794) (53,024) Amortization of intangibles assets (3,086) (2,554) (9,215) (7,293) Other acquisition-related expenses (243) (1,144) (859) (2,505) Other unallocated expenses (10,049) (12,650) (23,807) (30,966) Income from operations 96,396 80,565 267,331 218,105 Interest and other income, net 1,672 2,509 5,875 6,775 Foreign exchange gain/(loss) 5,896 (3,105) 3,253 (10,151) Income before provision for income taxes $ 103,964 $ 79,969 $ 276,459 $ 214,729 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. Physical locations and values of the Company’s long-lived assets are presented below: As of As of Belarus $ 72,507 $ 75,984 Ukraine 30,142 24,652 United States 16,329 15,637 Russia 13,686 17,980 India 6,349 7,443 Poland 5,032 5,029 Hungary 4,820 5,201 Spain 2,685 1,106 China 2,556 3,036 Mexico 2,431 2,353 Other 7,152 6,838 Total $ 163,689 $ 165,259 The table below presents information about the Company’s revenues by customer location for the three and nine months ended September 30, 2020 and 2019: Three Months Ended Nine Months Ended 2020 2019 2020 2019 United States $ 371,366 $ 340,803 $ 1,106,459 $ 959,471 United Kingdom 77,519 74,992 251,928 209,773 Switzerland 50,399 38,781 144,158 110,378 Netherlands 28,827 22,161 81,973 63,816 Russia 27,963 23,668 69,372 62,020 Germany 22,172 20,940 62,163 59,716 Canada 18,219 17,582 52,724 50,339 Other locations 55,778 49,176 167,208 145,510 Total $ 652,243 $ 588,103 $ 1,935,985 $ 1,661,023

BUSINESS AND SUMMARY OF SIGNI_2

BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Nature of Operations	EPAM Systems, Inc. (the “Company” or “EPAM”) is a leading global provider of digital platform engineering and software development services to customers located around the world, primarily in North America, Europe, Asia and Australia. The Company’s industry expertise includes financial services, travel and consumer, software and hi-tech, business information and media, life sciences and healthcare, as well as other emerging industries. The Company is incorporated in Delaware with headquarters in Newtown, Pennsylvania.
Basis of Presentation	Basis of Presentation — The accompanying unaudited condensed consolidated financial statements of EPAM have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP” or “U.S. GAAP”) and Article 10 of Regulation S-X under the Securities Exchange Act of 1934, as amended. The unaudited condensed consolidated financial statements include the financial statements of EPAM Systems, Inc. and its subsidiaries with all intercompany balances and transactions eliminated.
Use of Estimates	The preparation of these condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in these condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates, and such differences may be material to the condensed consolidated financial statements. Operating results for the interim periods are not necessarily indicative of results that may be expected to occur for the entire year. In management’s opinion, all adjustments considered necessary for a fair presentation of the accompanying unaudited condensed consolidated financial statements have been included, and all adjustments are of a normal and recurring nature.
Reclassifications	As previously disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, certain amounts recorded in the prior-period consolidated statement of cash flows presented have been reclassified to conform to the current-period financial statement presentation. These reclassifications had no effect on previously reported results of operations.
Adoption of New Accounting Standards	Adoption of New Accounting Standards Unless otherwise discussed below, the adoption of new accounting standards did not have a material impact on the Company’s consolidated financial position, results of operations, changes in stockholders’ equity and cash flows. Measurement of Credit Losses on Financial Instruments — In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this update changed how companies measure and recognize credit impairment for many financial assets. The new credit loss model requires companies to immediately recognize an estimate of credit losses expected to occur over the remaining life of the financial assets (including trade receivables) that are in the scope of the update. The update also made amendments to the current impairment model for held-to-maturity and available-for-sale debt securities and certain guarantees. The Company adopted Topic 326, effective January 1, 2020, using a modified-retrospective approach through a cumulative effect adjustment to retained earnings as of the beginning of the period of adoption. As a result of the adoption of Topic 326, the Company recorded an immaterial reduction to its allowance for doubtful accounts for trade receivables and contract assets . Pending Accounting Standards From time to time, new accounting pronouncements are issued by the FASB or other standards-setting bodies that the Company will adopt according to the various timetables the FASB specifies. The Company believes the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position, results of operations and cash flows upon adoption.

FAIR VALUE MEASUREMENTS (Polici

FAIR VALUE MEASUREMENTS (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Fair Value of Financial Instruments	The foreign exchange derivatives are valued using pricing models and discounted cash flow methodologies based on observable foreign exchange data at the measurement date. See Note 5 “Derivative Financial Instruments” in the condensed consolidated interim financial statements for additional information regarding derivative financial instruments. The fair value of the contingent consideration was determined using a probability-weighted expected return method and is based on 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. Although there is significant judgment involved, the Company believes its estimates and assumptions are reasonable. In determining fair value, the Company considered a variety of factors, including future performance of the acquired businesses using financial projections developed by the Company and market risk assumptions that were derived for revenue growth and earnings before interest and taxes. The Company estimated future payments using the earnout formula and performance targets specified in the purchase agreements and adjusted those estimates to reflect the probability of their achievement. Those weighted-average estimated future payments were then discounted to present value using a rate based on the weighted-average cost of capital of guideline companies. The discount rates used to determine the fair value of contingent consideration for the 2020 Acquisitions ranged from a minimum of 15.5% to a maximum of 17.5%. Changes in financial projections, market risk assumptions, discount rates or probability assumptions related to achieving the various earnout criteria would result in a change in the fair value of the recorded contingent liabilities. Such changes, if any, are recorded within Interest and other income, net in the Company’s condensed consolidated statement of income and comprehensive income.
Equity Securities without Readily Determinable Fair Value	The Company holds investments in equity securities that do not have readily determinable fair values. These investments are recorded at cost and are remeasured to fair value based on certain observable price changes or impairment events as they occur.

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Reporting of Cash Flow Hedges	The Company records changes in the fair value of its cash flow hedges in accumulated other comprehensive loss in the condensed consolidated balance sheets until the forecasted transaction occurs. When the forecasted transaction occurs, the Company reclassifies the related gain or loss on the cash flow hedge to cost of revenues (exclusive of depreciation and amortization). In the event the underlying forecasted transaction does not occur, or it becomes probable that it will not occur, the Company reclassifies the gain or loss on the related cash flow hedge into income.
Reporting of Derivative Activity	If the Company does not elect hedge accounting, or the contract does not qualify for hedge accounting treatment, the changes in fair value from period to period are recorded in income.

INCOME TAXES (Policies)

INCOME TAXES (Policies)	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	In determining its interim provision for income taxes, the Company uses an estimated annual effective tax rate, which is based on expected annual profit before tax, statutory tax rates and tax planning opportunities available in the various jurisdictions in which the Company operates. Certain significant or unusual items are separately recognized in the quarter in which they occur and can be a source of variability in the effective tax rates from quarter to quarter.

ACQUISITION (Tables)

ACQUISITION (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Fair Value of the Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed as of the date of acquisition as updated for any changes as of June 30, 2020 for test IO: test IO Cash and cash equivalents $ 663 Trade receivables and contract assets 621 Prepaid and other current assets 150 Goodwill 11,926 Intangible assets 6,219 Property and equipment and other noncurrent assets 305 Total assets acquired $ 19,884 Accounts payable, accrued expenses and other current liabilities $ 993 Other noncurrent liabilities 1,568 Total liabilities assumed $ 2,561 Net assets acquired $ 17,323

GOODWILL (Tables)

GOODWILL (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill By Reportable Segment	Goodwill by reportable segment was as follows: North America Europe Russia Total Balance as of January 1, 2020 $ 113,426 $ 80,873 $ 744 $ 195,043 test IO purchase accounting adjustment 863 (1,089) — (226) Other 2019 acquisitions purchase accounting adjustments 219 71 21 311 2020 Acquisitions 6,236 6,822 — 13,058 Effect of net foreign currency exchange rate changes 98 (457) (63) (422) Balance as of September 30, 2020 $ 120,842 $ 86,220 $ 702 $ 207,764

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following tables present the fair values of the Company’s financial assets and liabilities measured at fair value on a recurring basis as of September 30, 2020 and December 31, 2019: As of September 30, 2020 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 936 $ — $ 936 $ — Total assets measured at fair value on a recurring basis $ 936 $ — $ 936 $ — Foreign exchange derivative liabilities $ 3,689 $ — $ 3,689 $ — Contingent consideration 5,913 — — 5,913 Total liabilities measured at fair value on a recurring basis $ 9,602 $ — $ 3,689 $ 5,913 As of December 31, 2019 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 1,910 $ — $ 1,910 $ — Total assets measured at fair value on a recurring basis $ 1,910 $ — $ 1,910 $ — Foreign exchange derivative liabilities $ 243 $ — $ 243 $ — Contingent consideration 10,495 — — 10,495 Total liabilities measured at fair value on a recurring basis $ 10,738 $ — $ 243 $ 10,495
Acquisition-Related Contingent Consideration Roll Forward	A reconciliation of the beginning and ending balances of Level 3 acquisition-related contingent consideration using significant unobservable inputs for the nine months ended September 30, 2020 is as follows: Amount Contingent consideration liabilities as of January 1, 2020 $ 10,495 Payment of contingent consideration for previously acquired business (7,869) Acquisition date fair value of contingent consideration — 2020 Acquisitions (Note 2) 5,292 Changes in fair value of contingent consideration included in Interest and other income, net (1,480) Effect of net foreign currency exchange rate changes (525) Contingent consideration liabilities as of September 30, 2020 $ 5,913
Estimated Fair Values of Financial Assets and Liabilities not Measured at Fair Value on Recurring Basis	The following tables present the estimated fair values of the Company’s financial assets and liabilities not measured at fair value on a recurring basis as of the dates indicated: Fair Value Hierarchy Balance Estimated Fair Value Level 1 Level 2 Level 3 September 30, 2020 Financial Assets: Cash equivalents: Money market funds $ 171,903 $ 171,903 $ 171,903 $ — $ — Total cash equivalents $ 171,903 $ 171,903 $ 171,903 $ — $ — Restricted cash $ 1,158 $ 1,158 $ 1,158 $ — $ — Time deposits $ 60,089 $ 60,089 $ — $ 60,089 $ — Employee loans $ 1,168 $ 1,168 $ — $ — $ 1,168 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,006 $ 25,006 $ — $ 25,006 $ — Fair Value Hierarchy Balance Estimated Fair Value Level 1 Level 2 Level 3 December 31, 2019 Financial Assets: Cash equivalents: Money market funds $ 407,817 $ 407,817 $ 407,817 $ — $ — Time deposits 10,002 10,002 — 10,002 — Total cash equivalents $ 417,819 $ 417,819 $ 407,817 $ 10,002 $ — Restricted cash $ 1,136 $ 1,136 $ 1,136 $ — $ — Employee loans $ 2,434 $ 2,434 $ — $ — $ 2,434 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,017 $ 25,017 $ — $ 25,017 $ —

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivative Instruments	The fair value of derivative instruments on the Company’s consolidated balance sheets as of September 30, 2020 and December 31, 2019 were as follows: As of September 30, 2020 As of December 31, 2019 Balance Sheet Classification Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives Foreign exchange forward contracts - Prepaid expenses and other current assets $ 936 $ 1,910 Accrued expenses and other current liabilities $ 3,689 $ 243
Changes in the Fair Value of Derivative Instruments	The changes in the fair value of foreign currency derivative instruments in our unaudited condensed consolidated statements of income and comprehensive income for the three and nine months ended September 30, 2020 and 2019 were as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Foreign exchange forward contracts - Designated as hedging instruments: Net (loss)/gain in fair value recognized in accumulated other comprehensive loss $ (650) $ (2,791) $ (4,420) $ 3,192 Net (loss)/gain reclassified from accumulated other comprehensive loss into cost of revenues (exclusive of depreciation and amortization) $ (1,094) $ 848 $ (3,605) $ 738

LEASES (Tables)

LEASES (Tables)	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Components of Lease Expenses	During the three and nine months ended September 30, 2020 and 2019, the components of lease expense were as follows: Three Months Ended Nine Months Ended Income Statement Classification 2020 2019 2020 2019 Operating lease cost Selling, general and administrative expenses $ 18,437 $ 16,210 $ 56,151 $ 45,125 Variable lease cost Selling, general and administrative expenses 1,442 2,439 4,656 6,535 Short-term lease cost Selling, general and administrative expenses 180 1,085 989 2,989 Total lease cost $ 20,059 $ 19,734 $ 61,796 $ 54,649
Supplemental Cash Flow Information	Supplemental cash flow information related to leases for the three and nine months ended September 30, 2020 and 2019 was as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 17,952 $ 14,709 $ 51,324 $ 43,510 Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 2,277 $ 14,251 $ 45,205 $ 67,798 Non-cash net increase due to lease modifications: Operating lease right-of-use assets $ 11,726 $ 3,233 $ 7,744 $ 6,383 Operating lease liabilities $ 11,708 $ 3,199 $ 7,719 $ 6,451
Weighted Average Lease Terms and Discount Rates	Weighted average remaining lease term and discount rate as of September 30, 2020 and 2019 were as follows: As of September 30, 2020 As of September 30, 2019 Weighted average remaining lease term, in years: Operating leases 5.9 5.9 Weighted average discount rate: Operating leases 3.1 % 3.8 %
Maturity of Operating Lease Liabilities	As of September 30, 2020, operating lease liabilities will mature as follows: Year ending December 31, Lease Payments 2020 (excluding nine months ended September 30, 2020) $ 18,334 2021 63,652 2022 48,523 2023 35,343 2024 30,360 Thereafter 71,115 Total lease payments 267,327 Less: imputed interest (22,285) Total $ 245,042

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Outstanding Debt And Borrowing Capacity	The following table presents the outstanding debt and borrowing capacity of the Company under the 2017 Credit Facility: As of As of Outstanding debt $ 25,000 $ 25,000 Interest rate 1.2 % 2.8 % Irrevocable standby letters of credit $ — $ 303 Available borrowing capacity $ 275,000 $ 274,697 Current maximum borrowing capacity $ 300,000 $ 300,000

REVENUES (Tables)

REVENUES (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenues	The following tables present the disaggregation of the Company’s revenues by customer location, including a reconciliation of the disaggregated revenues with the reportable segments (Note 13 “Segment Information”) for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 378,493 $ 10,853 $ 630 $ 389,976 Europe 11,278 203,255 — 214,533 CIS 1,433 16 28,590 30,039 APAC 401 17,294 — 17,695 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 1,126,970 $ 32,107 $ 2,665 $ 1,161,742 Europe 32,805 615,843 6 648,654 CIS 6,223 32 70,722 76,977 APAC 1,538 47,074 — 48,612 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 349,875 $ 8,484 $ 42 $ 358,401 Europe 6,756 182,533 23 189,312 CIS 2,349 53 24,099 26,501 APAC 7 13,882 — 13,889 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Customer Locations North America $ 976,841 $ 32,926 $ 74 $ 1,009,841 Europe 16,722 523,180 263 540,165 CIS 6,093 66 63,607 69,766 APAC 1,045 40,206 — 41,251 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 The following tables present the disaggregation of the Company’s revenues by industry vertical, including a reconciliation of the disaggregated revenues with the reportable segments (Note 13 “Segment Information”) for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 84,384 $ 55,228 $ 402 $ 140,014 Financial Services 48,415 68,419 19,881 136,715 Software & Hi-Tech 100,847 17,492 515 118,854 Travel & Consumer 54,590 51,449 4,135 110,174 Life Sciences & Healthcare 66,071 7,963 169 74,203 Emerging Verticals 37,298 30,867 4,118 72,283 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 246,085 $ 171,712 $ 1,201 $ 418,998 Financial Services 143,970 202,668 49,695 396,333 Software & Hi-Tech 303,385 53,803 3,000 360,188 Travel & Consumer 161,507 163,769 11,698 336,974 Life Sciences & Healthcare 189,458 22,651 217 212,326 Emerging Verticals 123,131 80,453 7,582 211,166 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 65,153 $ 40,624 $ 22 $ 105,799 Financial Services 50,510 61,067 18,760 130,337 Software & Hi-Tech 90,880 16,952 552 108,384 Travel & Consumer 51,476 57,735 3,171 112,382 Life Sciences & Healthcare 60,049 6,713 7 66,769 Emerging Verticals 40,919 21,861 1,652 64,432 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Industry Verticals Business Information & Media $ 189,854 $ 108,846 $ 266 $ 298,966 Financial Services 132,421 181,781 49,801 364,003 Software & Hi-Tech 255,601 56,762 1,470 313,833 Travel & Consumer 146,654 169,112 8,056 323,822 Life Sciences & Healthcare 164,492 16,176 73 180,741 Emerging Verticals 111,679 63,701 4,278 179,658 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 The following tables present the disaggregation of the Company’s revenues by contract type including a reconciliation of the disaggregated revenues with the Company’s reportable segments (Note 13 “Segment Information”) for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 348,570 $ 196,719 $ 13,844 $ 559,133 Fixed-price 41,050 34,057 15,314 90,421 Licensing 1,717 242 53 2,012 Other revenues 268 400 9 677 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 1,054,548 $ 579,212 $ 41,412 $ 1,675,172 Fixed-price 106,760 111,565 30,394 248,719 Licensing 5,445 949 1,520 7,914 Other revenues 783 3,330 67 4,180 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 322,573 $ 171,261 $ 13,815 $ 507,649 Fixed-price 35,273 33,093 10,304 78,670 Licensing 883 149 9 1,041 Other revenues 258 449 36 743 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Contract Types Time-and-material $ 907,624 $ 507,055 $ 37,134 $ 1,451,813 Fixed-price 89,694 87,543 26,534 203,771 Licensing 2,343 689 211 3,243 Other revenues 1,040 1,091 65 2,196 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023 Timing of Revenue Recognition The following tables present the timing of revenue recognition for the periods indicated: Three Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 390,295 $ 231,281 $ 29,174 $ 650,750 Transferred at a point of time 1,310 137 46 1,493 Revenues $ 391,605 $ 231,418 $ 29,220 $ 652,243 Nine Months Ended September 30, 2020 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 1,163,678 $ 694,525 $ 71,882 $ 1,930,085 Transferred at a point of time 3,858 531 1,511 5,900 Revenues $ 1,167,536 $ 695,056 $ 73,393 $ 1,935,985 Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 358,426 $ 204,833 $ 24,110 $ 587,369 Transferred at a point of time 561 119 54 734 Revenues $ 358,987 $ 204,952 $ 24,164 $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Consolidated Revenues Timing of Revenue Recognition Transferred over time $ 999,530 $ 596,106 $ 63,890 $ 1,659,526 Transferred at a point of time 1,171 272 54 1,497 Revenues $ 1,000,701 $ 596,378 $ 63,944 $ 1,661,023
Revenue Expected to be Recognized in Future Related to Remaining Performance Obligations	The following table includes the estimated revenues expected to be recognized in the future related to performance obligations that are partially or fully unsatisfied as of September 30, 2020. The Company applies a practical expedient and does not disclose the value of unsatisfied performance obligations for contracts that (i) have an original expected duration of one year or less and (ii) contracts for which it recognizes revenues at the amount to which it has the right to invoice for services provided: Less than 1 year 1 Year 2 Years 3 Years Total Contract Type Fixed-price $ 19,644 $ 288 $ — $ — $ 19,932
Contract Balances	The following table provides information on the classification of contract assets and liabilities in the condensed consolidated balance sheets: As of As of Contract assets included in Trade receivables and contract assets $ 21,548 $ 14,320 Contract liabilities included in Accrued expenses and other current liabilities $ 12,415 $ 9,132

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2020
Share-based Payment Arrangement [Abstract]
Components of Stock-Based Compensation Expenses	The following table summarizes the components of stock-based compensation expense recognized in the Company’s condensed consolidated statements of income and comprehensive income for the periods indicated: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Cost of revenues (exclusive of depreciation and amortization) $ 10,854 $ 7,580 $ 23,796 $ 27,841 Selling, general and administrative expenses 12,620 7,891 30,998 25,183 Total $ 23,474 $ 15,471 $ 54,794 $ 53,024
Stock Options Activity	Stock option activity under the Company’s plans is set forth below: Number of Weighted Average Aggregate Weighted Average Options outstanding at January 1, 2020 3,322,930 $ 50.85 Options granted 147,351 $ 176.21 Options modified (198) $ 73.27 Options exercised (592,904) $ 38.76 Options forfeited/cancelled (9,137) $ 117.40 Options outstanding at September 30, 2020 2,868,042 $ 59.58 $ 756,305 4.5 Options vested and exercisable at September 30, 2020 2,489,928 $ 46.31 $ 689,630 3.9 Options expected to vest at September 30, 2020 353,203 $ 145.98 $ 62,624 8.4
Service-Based Awards Activity	The table below summarizes activity related to the Company’s equity-classified and liability-classified service-based awards for the nine months ended September 30, 2020: Equity-Classified Restricted Stock Equity-Classified Equity-Settled Restricted Stock Units Liability-Classified Cash-Settled Restricted Stock Units Number of Shares Weighted Average Grant Date Number of Shares Weighted Average Grant Date Number of Shares Weighted Average Grant Date Unvested service-based awards outstanding at January 1, 2020 9,791 $ 162.96 758,785 $ 122.48 242,288 $ 105.40 Awards granted — $ — 252,376 $ 180.39 59,770 $ 180.37 Awards modified — $ — (1,237) $ 122.55 — $ — Awards vested (397) $ 63.10 (298,331) $ 107.31 (121,399) $ 91.22 Awards forfeited/cancelled — $ — (35,446) $ 140.33 (4,106) $ 112.58 Unvested service-based awards outstanding at September 30, 2020 9,394 $ 167.18 676,147 $ 149.85 176,553 $ 140.36
Performance-Based Awards Activity	The table below summarizes activity related to the Company’s equity-classified performance-based awards for the nine months ended September 30, 2020: Equity-Classified Equity-Settled Restricted Stock Equity-Classified Equity-Settled Restricted Stock Units Number of Shares Weighted Average Grant Date Number of Shares Weighted Average Grant Date Unvested performance-based awards outstanding at January 1, 2020 9,393 $ 165.87 — $ — Awards granted — $ — 31,354 $ 210.44 Unvested performance-based awards outstanding at September 30, 2020 9,393 $ 165.87 31,354 $ 210.44

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2020
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: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Numerator for basic and diluted earnings per share: Net income $ 89,432 $ 67,002 $ 241,621 $ 186,533 Numerator for basic and diluted earnings per share $ 89,432 $ 67,002 $ 241,621 $ 186,533 Denominator: Weighted average common shares for basic earnings per share 55,883,879 54,877,666 55,624,727 54,603,903 Net effect of dilutive stock options, restricted stock units and restricted stock awards 2,732,227 2,966,689 2,716,451 2,963,436 Weighted average common shares for diluted earnings per share 58,616,106 57,844,355 58,341,178 57,567,339 Net income per share: Basic $ 1.60 $ 1.22 $ 4.34 $ 3.42 Diluted $ 1.53 $ 1.16 $ 4.14 $ 3.24

SEGMENTS INFORMATION (Tables)

SEGMENTS INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Revenues from External Customers and Operating Profit/(Loss), Before Unallocated Expenses	Revenues from external customers and operating profit/(loss), before unallocated expenses, by reportable segment for the three and nine months ended September 30, 2020 and 2019, were as follows: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Segment revenues: North America $ 391,605 $ 358,987 $ 1,167,536 $ 1,000,701 Europe 231,418 204,952 695,056 596,378 Russia 29,220 24,164 73,393 63,944 Total segment revenues $ 652,243 $ 588,103 $ 1,935,985 $ 1,661,023 Segment operating profit/(loss): North America $ 87,272 $ 79,310 $ 248,951 $ 213,114 Europe 43,018 27,550 109,223 87,014 Russia 2,958 5,524 (2,168) 11,765 Total segment operating profit $ 133,248 $ 112,384 $ 356,006 $ 311,893
Reconciliation of Segment Operating Profit to Consolidated Income Before Provision for Income Taxes	Reconciliation of segment operating profit to consolidated income before provision for income taxes is presented below: Three Months Ended Nine Months Ended 2020 2019 2020 2019 Total segment operating profit: $ 133,248 $ 112,384 $ 356,006 $ 311,893 Unallocated amounts: Stock-based compensation expense (23,474) (15,471) (54,794) (53,024) Amortization of intangibles assets (3,086) (2,554) (9,215) (7,293) Other acquisition-related expenses (243) (1,144) (859) (2,505) Other unallocated expenses (10,049) (12,650) (23,807) (30,966) Income from operations 96,396 80,565 267,331 218,105 Interest and other income, net 1,672 2,509 5,875 6,775 Foreign exchange gain/(loss) 5,896 (3,105) 3,253 (10,151) Income before provision for income taxes $ 103,964 $ 79,969 $ 276,459 $ 214,729
Physical Location and Values of Long-Lived Assets	Physical locations and values of the Company’s long-lived assets are presented below: As of As of Belarus $ 72,507 $ 75,984 Ukraine 30,142 24,652 United States 16,329 15,637 Russia 13,686 17,980 India 6,349 7,443 Poland 5,032 5,029 Hungary 4,820 5,201 Spain 2,685 1,106 China 2,556 3,036 Mexico 2,431 2,353 Other 7,152 6,838 Total $ 163,689 $ 165,259
Revenues by Customer Location	The table below presents information about the Company’s revenues by customer location for the three and nine months ended September 30, 2020 and 2019: Three Months Ended Nine Months Ended 2020 2019 2020 2019 United States $ 371,366 $ 340,803 $ 1,106,459 $ 959,471 United Kingdom 77,519 74,992 251,928 209,773 Switzerland 50,399 38,781 144,158 110,378 Netherlands 28,827 22,161 81,973 63,816 Russia 27,963 23,668 69,372 62,020 Germany 22,172 20,940 62,163 59,716 Canada 18,219 17,582 52,724 50,339 Other locations 55,778 49,176 167,208 145,510 Total $ 652,243 $ 588,103 $ 1,935,985 $ 1,661,023

ACQUISITION (Narrative) (Detail

ACQUISITION (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Business Acquisition [Line Items]
Revenues	$ 652,243	$ 588,103	$ 1,935,985	$ 1,661,023
2020 Acquisitions
Business Acquisition [Line Items]
Number of acquisitions			2
Purchase price including contingent consideration	22,526		$ 22,526
Contingent consideration fair value	5,292		5,292
Maximum amount of earnout payable	18,582		18,582
Intangible assets	7,280		7,280
Revenues	$ 1,245		$ 3,478

ACQUISITION (Fair Value of the

ACQUISITION (Fair Value of the Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	6 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020	Dec. 31, 2019	Apr. 30, 2019
Business Acquisition [Line Items]
Goodwill		$ 207,764	$ 195,043
test IO
Business Acquisition [Line Items]
Cash and cash equivalents				$ 663
Trade receivables and contract assets				621
Prepaid and other current assets				150
Goodwill				11,926
Intangible assets				6,219
Property and equipment and other noncurrent assets				305
Total assets acquired				19,884
Accounts payable, accrued expenses and other current liabilities				993
Other noncurrent liabilities				1,568
Total liabilities assumed				2,561
Net assets acquired				$ 17,323
Decrease to goodwill	$ 226	$ 226

GOODWILL (Goodwill Roll Forward

GOODWILL (Goodwill Roll Forward) (Details) - USD ($) $ in Thousands	6 Months Ended	9 Months Ended
	Jun. 30, 2020	Sep. 30, 2020
Goodwill [Roll Forward]
Balance as of January 1, 2020	$ 195,043	$ 195,043
Effect of net foreign currency exchange rate changes		(422)
Balance as of September 30, 2020		207,764
test IO
Goodwill [Roll Forward]
Purchase accounting adjustments	(226)	(226)
Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		311
2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		13,058
North America
Goodwill [Roll Forward]
Balance as of January 1, 2020	113,426	113,426
Effect of net foreign currency exchange rate changes		98
Balance as of September 30, 2020		120,842
North America | test IO
Goodwill [Roll Forward]
Purchase accounting adjustments		863
North America | Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		219
North America | 2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		6,236
Europe
Goodwill [Roll Forward]
Balance as of January 1, 2020	80,873	80,873
Effect of net foreign currency exchange rate changes		(457)
Balance as of September 30, 2020		86,220
Europe | test IO
Goodwill [Roll Forward]
Purchase accounting adjustments		(1,089)
Europe | Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		71
Europe | 2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		6,822
Russia
Goodwill [Roll Forward]
Balance as of January 1, 2020	$ 744	744
Effect of net foreign currency exchange rate changes		(63)
Balance as of September 30, 2020		702
Russia | test IO
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Russia | Other 2019 Acquisitions
Goodwill [Roll Forward]
Purchase accounting adjustments		21
Russia | 2020 Acquisitions
Goodwill [Roll Forward]
Acquisition		$ 0

GOODWILL (Goodwill Accumulated

GOODWILL (Goodwill Accumulated Impairment Losses) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
North America
Goodwill [Line Items]
Accumulated impairment loss	$ 0	$ 0
Europe
Goodwill [Line Items]
Accumulated impairment loss	0	0
Russia
Goodwill [Line Items]
Accumulated impairment loss	$ 2,241	$ 2,241

FAIR VALUE MEASUREMENTS (Financ

FAIR VALUE MEASUREMENTS (Financial Assets and Liabilities at Fair Value on Recurring Basis) (Details) - Recurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financial Assets:
Total assets measured at fair value on a recurring basis	$ 936	$ 1,910
Financial Liabilities:
Contingent consideration	5,913	10,495
Total liabilities measured at fair value on a recurring basis	9,602	10,738
Foreign exchange contracts
Financial Assets:
Derivative assets	936	1,910
Financial Liabilities:
Derivative liabilities	3,689	243
Level 1
Financial Assets:
Total assets measured at fair value on a recurring basis	0	0
Financial Liabilities:
Contingent consideration	0	0
Total liabilities measured at fair value on a recurring basis	0	0
Level 1 | Foreign exchange contracts
Financial Assets:
Derivative assets	0	0
Financial Liabilities:
Derivative liabilities	0	0
Level 2
Financial Assets:
Total assets measured at fair value on a recurring basis	936	1,910
Financial Liabilities:
Contingent consideration	0	0
Total liabilities measured at fair value on a recurring basis	3,689	243
Level 2 | Foreign exchange contracts
Financial Assets:
Derivative assets	936	1,910
Financial Liabilities:
Derivative liabilities	3,689	243
Level 3
Financial Assets:
Total assets measured at fair value on a recurring basis	0	0
Financial Liabilities:
Contingent consideration	5,913	10,495
Total liabilities measured at fair value on a recurring basis	5,913	10,495
Level 3 | Foreign exchange contracts
Financial Assets:
Derivative assets	0	0
Financial Liabilities:
Derivative liabilities	$ 0	$ 0

FAIR VALUE MEASUREMENTS (Acquis

FAIR VALUE MEASUREMENTS (Acquisition-Related Contingent Consideration Roll Forward) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Discount rate | 2020 Acquisitions | Maximum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Measurement input to determine fair value of contingent consideration	0.175
Discount rate | 2020 Acquisitions | Minimum
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Measurement input to determine fair value of contingent consideration	0.155
Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration liabilities as of January 1, 2020	$ 10,495
Payment of contingent consideration for previously acquired business	(7,869)
Effect of net foreign currency exchange rate changes	(525)
Contingent consideration liabilities as of September 30, 2020	5,913
Level 3 | Interest and other income, net
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Changes in the fair value of contingent consideration	(1,480)
Level 3 | 2020 Acquisitions
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contingent consideration	$ 5,292

FAIR VALUE MEASUREMENTS (Estima

FAIR VALUE MEASUREMENTS (Estimated Fair Values of the Financial Assets and Liabilities not Measured at Fair Value on a Recurring Basis) (Details) - Nonrecurring - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Level 1
Financial Assets:
Cash equivalents:		$ 407,817
Restricted cash		1,136
Employee loans		0
Level 1 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings		0
Level 2
Financial Assets:
Cash equivalents:		10,002
Restricted cash		0
Employee loans		0
Level 2 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings		25,017
Level 3
Financial Assets:
Cash equivalents:		0
Restricted cash		0
Employee loans		2,434
Level 3 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings		0
Balance
Financial Assets:
Cash equivalents:	$ 171,903	417,819
Restricted cash	1,158	1,136
Employee loans	1,168	2,434
Balance | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	25,006	25,017
Estimated Fair Value
Financial Assets:
Cash equivalents:	171,903	417,819
Restricted cash	1,158	1,136
Employee loans	1,168	2,434
Estimated Fair Value | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	25,006	25,017
Estimated Fair Value | Level 1
Financial Assets:
Cash equivalents:	171,903
Restricted cash	1,158	1,136
Employee loans	0	0
Estimated Fair Value | Level 1 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	0	0
Estimated Fair Value | Level 2
Financial Assets:
Cash equivalents:	0
Restricted cash	0	0
Employee loans	0	0
Estimated Fair Value | Level 2 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	25,006	25,017
Estimated Fair Value | Level 3
Financial Assets:
Cash equivalents:	0
Restricted cash	0	0
Employee loans	1,168	2,434
Estimated Fair Value | Level 3 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	0	0
Money market funds | Level 1
Financial Assets:
Cash equivalents:		407,817
Money market funds | Level 2
Financial Assets:
Cash equivalents:		0
Money market funds | Level 3
Financial Assets:
Cash equivalents:		0
Money market funds | Balance
Financial Assets:
Cash equivalents:	171,903	407,817
Money market funds | Estimated Fair Value
Financial Assets:
Cash equivalents:	171,903	407,817
Money market funds | Estimated Fair Value | Level 1
Financial Assets:
Cash equivalents:	171,903	407,817
Money market funds | Estimated Fair Value | Level 2
Financial Assets:
Cash equivalents:	0	0
Money market funds | Estimated Fair Value | Level 3
Financial Assets:
Cash equivalents:	0	0
Time deposits | Level 1
Financial Assets:
Cash equivalents:		0
Time deposits | Level 2
Financial Assets:
Cash equivalents:		10,002
Time deposits | Level 3
Financial Assets:
Cash equivalents:		0
Time deposits | Balance
Financial Assets:
Cash equivalents:		10,002
Short-term investments	60,089
Time deposits | Estimated Fair Value
Financial Assets:
Cash equivalents:		10,002
Short-term investments	60,089
Time deposits | Estimated Fair Value | Level 1
Financial Assets:
Cash equivalents:		0
Short-term investments	0
Time deposits | Estimated Fair Value | Level 2
Financial Assets:
Cash equivalents:		10,002
Short-term investments	60,089
Time deposits | Estimated Fair Value | Level 3
Financial Assets:
Cash equivalents:		$ 0
Short-term investments	$ 0

FAIR VALUE MEASUREMENTS (Equity

FAIR VALUE MEASUREMENTS (Equity Securities Without Readily Determinable Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Other noncurrent assets
Equity Securities without Readily Determinable Fair Value [Line Items]
Carrying amount of equity securities that do not have readily determinable fair values	$ 25,000	$ 5,750

DERIVATIVE FINANCIAL INSTRUME_4

DERIVATIVE FINANCIAL INSTRUMENTS (Fair Value of Derivative Instruments) (Details) - Foreign exchange contracts - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Financial collateral (including cash collateral) required to be posted	$ 0
Designated as hedging instruments | Cash flow hedging | Prepaid expenses and other current assets
Derivatives, Fair Value [Line Items]
Asset Derivatives	936	$ 1,910
Designated as hedging instruments | Cash flow hedging | Accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 3,689	$ 243

DERIVATIVE FINANCIAL INSTRUME_5

DERIVATIVE FINANCIAL INSTRUMENTS (Changes in the Fair Value of Derivative Instruments) (Details) - Foreign exchange contracts - Designated as hedging instruments - Cash flow hedging - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cost of revenues (exclusive of depreciation and amortization)
Derivative Instruments, Gain (Loss) [Line Items]
Net (loss)/gain reclassified	$ (1,094)	$ 848	$ (3,605)	$ 738
Accumulated other comprehensive loss
Derivative Instruments, Gain (Loss) [Line Items]
Net (loss)/gain in fair value	$ (650)	$ (2,791)	$ (4,420)	$ 3,192

LEASES (Narrative) (Details)

LEASES (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Lessee, Lease, Description [Line Items]
Operating leases description	The Company leases office space, corporate apartments, office equipment, and vehicles
Terms and conditions of variable lease payments	Many of the Company’s leases contain variable payments including changes in base rent and charges for common area maintenance or other miscellaneous expenses
Existence of options to extend	true
Existence of options to terminate	true
Description of operating leases that have not yet commenced	The Company had committed to payments of $5,724 related to operating lease agreements that had not yet commenced as of September 30, 2020. These operating leases will commence on various dates during 2020 with lease terms ranging from 1.0 to 5.0 years
Description of finance leases that have not yet commenced	The Company did not have any material finance lease agreements that had not yet commenced.
Commitments related to operating lease agreements that have not yet commenced	$ 5,724
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 month 6 days
Lease term of lease agreements that have not yet commenced	1 year 7 days
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	10 years 7 months 6 days
Lease term of lease agreements that have not yet commenced	5 years

LEASES (Components of Lease Exp

LEASES (Components of Lease Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lease, Cost [Line Items]
Total lease cost	$ 20,059	$ 19,734	$ 61,796	$ 54,649
Selling, general and administrative expenses
Lease, Cost [Line Items]
Operating lease cost	18,437	16,210	56,151	45,125
Variable lease cost	1,442	2,439	4,656	6,535
Short-term lease cost	$ 180	$ 1,085	$ 989	$ 2,989

LEASES (Supplemental Cash Flow

LEASES (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows used for operating leases	$ 17,952	$ 14,709	$ 51,324	$ 43,510
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	2,277	14,251	45,205	67,798
Non-cash net increase due to lease modifications:
Operating lease right-of-use assets	11,726	3,233	7,744	6,383
Operating lease liabilities	$ 11,708	$ 3,199	$ 7,719	$ 6,451

LEASES (Weighted Average Lease

LEASES (Weighted Average Lease Terms and Discount Rates) (Details)	Sep. 30, 2020	Dec. 31, 2019
Weighted average remaining lease term, in years:
Operating leases	5 years 10 months 24 days	5 years 10 months 24 days
Weighted average discount rate:
Operating leases	3.10%	3.80%

LEASES (Maturity of Operating L

LEASES (Maturity of Operating Lease Liabilities) (Details) $ in Thousands	Sep. 30, 2020USD ($)
Leases [Abstract]
2020 (excluding nine months ended September 30, 2020)	$ 18,334
2021	63,652
2022	48,523
2023	35,343
2024	30,360
Thereafter	71,115
Total lease payments	267,327
Less: imputed interest	(22,285)
Total	$ 245,042

LONG-TERM DEBT (Details)

LONG-TERM DEBT (Details) - Credit Facility 2017 - USD ($) $ in Thousands	May 24, 2017	Sep. 30, 2020	Dec. 31, 2019
Revolving credit facility
Debt Instrument [Line Items]
Maturity date	May 24, 2022
Revolving credit facility | Overnight Bank Funding Rate
Debt Instrument [Line Items]
Variable interest rate spread	0.50%
Revolving credit facility | Daily LIBOR Rate
Debt Instrument [Line Items]
Variable interest rate spread	1.00%
Revolving credit facility | U.S. dollars
Debt Instrument [Line Items]
Line of credit, current borrowing capacity	$ 300,000
Line of credit, maximum borrowing capacity	400,000
Outstanding debt		$ 25,000	$ 25,000
Interest rate		1.20%	2.80%
Available borrowing capacity		$ 275,000	$ 274,697
Revolving credit facility | U.S. dollars | Maximum
Debt Instrument [Line Items]
Line of credit, current borrowing capacity		300,000	300,000
Revolving credit facility | Other currencies, excluding U.S. dollars
Debt Instrument [Line Items]
Line of credit, maximum borrowing capacity	$ 100,000
Standby letters of credit
Debt Instrument [Line Items]
Irrevocable standby letters of credit		$ 0	$ 303

REVENUES (Disaggregation of Rev

REVENUES (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Revenues	$ 652,243	$ 588,103	$ 1,935,985	$ 1,661,023
Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	650,750	587,369	1,930,085	1,659,526
Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	1,493	734	5,900	1,497
Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	559,133	507,649	1,675,172	1,451,813
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	90,421	78,670	248,719	203,771
Licensing
Disaggregation of Revenue [Line Items]
Revenues	2,012	1,041	7,914	3,243
Other revenues
Disaggregation of Revenue [Line Items]
Revenues	677	743	4,180	2,196
Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	140,014	105,799	418,998	298,966
Financial Services
Disaggregation of Revenue [Line Items]
Revenues	136,715	130,337	396,333	364,003
Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	118,854	108,384	360,188	313,833
Travel & Consumer
Disaggregation of Revenue [Line Items]
Revenues	110,174	112,382	336,974	323,822
Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	74,203	66,769	212,326	180,741
Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	72,283	64,432	211,166	179,658
North America
Disaggregation of Revenue [Line Items]
Revenues	389,976	358,401	1,161,742	1,009,841
Europe
Disaggregation of Revenue [Line Items]
Revenues	214,533	189,312	648,654	540,165
CIS
Disaggregation of Revenue [Line Items]
Revenues	30,039	26,501	76,977	69,766
APAC
Disaggregation of Revenue [Line Items]
Revenues	17,695	13,889	48,612	41,251
North America
Disaggregation of Revenue [Line Items]
Revenues	391,605	358,987	1,167,536	1,000,701
North America | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	390,295	358,426	1,163,678	999,530
North America | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	1,310	561	3,858	1,171
North America | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	348,570	322,573	1,054,548	907,624
North America | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	41,050	35,273	106,760	89,694
North America | Licensing
Disaggregation of Revenue [Line Items]
Revenues	1,717	883	5,445	2,343
North America | Other revenues
Disaggregation of Revenue [Line Items]
Revenues	268	258	783	1,040
North America | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	84,384	65,153	246,085	189,854
North America | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	48,415	50,510	143,970	132,421
North America | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	100,847	90,880	303,385	255,601
North America | Travel & Consumer
Disaggregation of Revenue [Line Items]
Revenues	54,590	51,476	161,507	146,654
North America | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	66,071	60,049	189,458	164,492
North America | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	37,298	40,919	123,131	111,679
North America | North America
Disaggregation of Revenue [Line Items]
Revenues	378,493	349,875	1,126,970	976,841
North America | Europe
Disaggregation of Revenue [Line Items]
Revenues	11,278	6,756	32,805	16,722
North America | CIS
Disaggregation of Revenue [Line Items]
Revenues	1,433	2,349	6,223	6,093
North America | APAC
Disaggregation of Revenue [Line Items]
Revenues	401	7	1,538	1,045
Europe
Disaggregation of Revenue [Line Items]
Revenues	231,418	204,952	695,056	596,378
Europe | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	231,281	204,833	694,525	596,106
Europe | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	137	119	531	272
Europe | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	196,719	171,261	579,212	507,055
Europe | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	34,057	33,093	111,565	87,543
Europe | Licensing
Disaggregation of Revenue [Line Items]
Revenues	242	149	949	689
Europe | Other revenues
Disaggregation of Revenue [Line Items]
Revenues	400	449	3,330	1,091
Europe | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	55,228	40,624	171,712	108,846
Europe | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	68,419	61,067	202,668	181,781
Europe | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	17,492	16,952	53,803	56,762
Europe | Travel & Consumer
Disaggregation of Revenue [Line Items]
Revenues	51,449	57,735	163,769	169,112
Europe | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	7,963	6,713	22,651	16,176
Europe | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	30,867	21,861	80,453	63,701
Europe | North America
Disaggregation of Revenue [Line Items]
Revenues	10,853	8,484	32,107	32,926
Europe | Europe
Disaggregation of Revenue [Line Items]
Revenues	203,255	182,533	615,843	523,180
Europe | CIS
Disaggregation of Revenue [Line Items]
Revenues	16	53	32	66
Europe | APAC
Disaggregation of Revenue [Line Items]
Revenues	17,294	13,882	47,074	40,206
Russia
Disaggregation of Revenue [Line Items]
Revenues	29,220	24,164	73,393	63,944
Russia | Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	29,174	24,110	71,882	63,890
Russia | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	46	54	1,511	54
Russia | Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	13,844	13,815	41,412	37,134
Russia | Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	15,314	10,304	30,394	26,534
Russia | Licensing
Disaggregation of Revenue [Line Items]
Revenues	53	9	1,520	211
Russia | Other revenues
Disaggregation of Revenue [Line Items]
Revenues	9	36	67	65
Russia | Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	402	22	1,201	266
Russia | Financial Services
Disaggregation of Revenue [Line Items]
Revenues	19,881	18,760	49,695	49,801
Russia | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	515	552	3,000	1,470
Russia | Travel & Consumer
Disaggregation of Revenue [Line Items]
Revenues	4,135	3,171	11,698	8,056
Russia | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	169	7	217	73
Russia | Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	4,118	1,652	7,582	4,278
Russia | North America
Disaggregation of Revenue [Line Items]
Revenues	630	42	2,665	74
Russia | Europe
Disaggregation of Revenue [Line Items]
Revenues	0	23	6	263
Russia | CIS
Disaggregation of Revenue [Line Items]
Revenues	28,590	24,099	70,722	63,607
Russia | APAC
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0	$ 0	$ 0

REVENUES (Revenue Expected to b

REVENUES (Revenue Expected to be Recognized in Future Related to Remaining Performance Obligations) (Details) - Fixed-price $ in Thousands	Sep. 30, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenues expected to be recognized in the future	$ 19,932
Less than 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenues expected to be recognized in the future	19,644
1 Year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenues expected to be recognized in the future	288
2 Years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenues expected to be recognized in the future	0
3 Years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenues expected to be recognized in the future	$ 0

REVENUES (Contract Balances) (D

REVENUES (Contract Balances) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Change in Contract with Customer, Liability [Abstract]
Revenue recognized	$ 439	$ 140	$ 8,301	$ 3,801
Revenues from performance obligations satisfied in previous period	9,105	$ 4,915	4,719	$ 7,039
Trade receivables and contract assets
Change in Contract with Customer, Liability [Abstract]
Contract assets	21,548		21,548		$ 14,320
Accrued expenses and other current liabilities
Change in Contract with Customer, Liability [Abstract]
Contract liabilties	$ 12,415		$ 12,415		$ 9,132

STOCK-BASED COMPENSATION (Compo

STOCK-BASED COMPENSATION (Components of Stock-Based Compensation Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 23,474	$ 15,471	$ 54,794	$ 53,024
Cost of revenues (exclusive of depreciation and amortization)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	10,854	7,580	23,796	27,841
Selling, general and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 12,620	$ 7,891	$ 30,998	$ 25,183

STOCK-BASED COMPENSATION (Stock

STOCK-BASED COMPENSATION (Stock Options Activity) (Details) - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2020
Number of Options
Options outstanding at January 1, 2020	3,322,930
Options granted	147,351
Options modified	(198)
Options exercised	(592,904)
Options forfeited/cancelled	(9,137)
Options outstanding at September 30, 2020	2,868,042
Options vested and exercisable at September 30, 2020	2,489,928
Options expected to vest at September 30, 2020	353,203
Weighted Average Exercise Price
Options outstanding at January 1, 2020	$ 50.85
Options granted	176.21
Options modified	73.27
Options exercised	38.76
Options forfeited/cancelled	117.40
Options outstanding at September 30, 2020	59.58
Options vested and exercisable at September 30, 2020	46.31
Options expected to vest at September 30, 2020	$ 145.98
Aggregate Intrinsic Value
Options outstanding at September 30, 2020	$ 756,305
Options vested and exercisable at September 30, 2020	689,630
Options expected to vest at September 30, 2020	$ 62,624
Weighted Average Remaining Contractual Term (in years)
Options outstanding at September 30, 2020	4 years 6 months
Options vested and exercisable at September 30, 2020	3 years 10 months 24 days
Options expected to vest at September 30, 2020	8 years 4 months 24 days

STOCK-BASED COMPENSATION (Sto_2

STOCK-BASED COMPENSATION (Stock Option Additional Information) (Details) - Employee Stock Option $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 15,575
Weighted-average remaining requisite service period	2 years 9 months 18 days

STOCK-BASED COMPENSATION (Restr

STOCK-BASED COMPENSATION (Restricted Stock and Restricted Stock Units Activity) (Details) - $ / shares	3 Months Ended	9 Months Ended
	Mar. 31, 2020	Sep. 30, 2020
Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock
Number of Shares
Unvested awards outstanding at January 1, 2020	9,791	9,791
Awards granted		0
Awards modified		0
Awards vested		(397)
Awards forfeited/cancelled		0
Unvested awards outstanding at June 30, 2020		9,394
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2020	$ 162.96	$ 162.96
Awards granted		0
Awards modified		0
Awards vested		63.10
Awards forfeited/cancelled		0
Unvested awards outstanding at June 30, 2020		$ 167.18
Service Period | Equity Classified Award | Equity-Settled Award | Restricted stock units
Number of Shares
Unvested awards outstanding at January 1, 2020	758,785	758,785
Awards granted		252,376
Awards modified		(1,237)
Awards vested		(298,331)
Awards forfeited/cancelled		(35,446)
Unvested awards outstanding at June 30, 2020		676,147
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2020	$ 122.48	$ 122.48
Awards granted		180.39
Awards modified		122.55
Awards vested		107.31
Awards forfeited/cancelled		140.33
Unvested awards outstanding at June 30, 2020		$ 149.85
Service Period | Liability Classified Award | Cash-Settled Award | Restricted stock units
Number of Shares
Unvested awards outstanding at January 1, 2020	242,288	242,288
Awards granted		59,770
Awards modified		0
Awards vested		(121,399)
Awards forfeited/cancelled		(4,106)
Unvested awards outstanding at June 30, 2020		176,553
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2020	$ 105.40	$ 105.40
Awards granted		180.37
Awards modified		0
Awards vested		91.22
Awards forfeited/cancelled		112.58
Unvested awards outstanding at June 30, 2020		$ 140.36
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted Stock
Number of Shares
Unvested awards outstanding at January 1, 2020	9,393	9,393
Awards granted		0
Unvested awards outstanding at June 30, 2020		9,393
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2020	$ 165.87	$ 165.87
Awards granted		0
Unvested awards outstanding at June 30, 2020		$ 165.87
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted stock units
Number of Shares
Unvested awards outstanding at January 1, 2020	0	0
Awards granted		31,354
Unvested awards outstanding at June 30, 2020		31,354
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2020	$ 0	$ 0
Awards granted		210.44
Unvested awards outstanding at June 30, 2020		$ 210.44
2020 Acquisitions | Service Period | Equity Classified Award | Equity-Settled Award | Restricted stock units
Number of Shares
Awards granted		19,201
2020 Acquisitions | Service Period | Liability Classified Award | Cash-Settled Award | Restricted stock units
Number of Shares
Awards granted		9,736
2020 Acquisitions | Performance Target | Equity Classified Award | Equity-Settled Award | Restricted stock units
Number of Shares
Awards granted		6,518
2019 Acquisitions | Service Period | Equity Classified Award | Equity-Settled Award | Restricted stock units
Number of Shares
Awards granted	5,793
2019 Acquisitions | Performance Target | Equity Classified Award | Equity-Settled Award | Restricted stock units
Number of Shares
Awards granted		24,836

STOCK-BASED COMPENSATION (Res_2

STOCK-BASED COMPENSATION (Restricted Stock and Restricted Stock Units Additional Information) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 897
Weighted-average remaining requisite service period	1 year 10 months 24 days
Service Period | Equity Classified Award | Equity-Settled Award | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 73,991
Weighted-average remaining requisite service period	2 years 7 months 6 days
Service Period | Liability Classified Award | Cash-Settled Award | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 34,399
Weighted-average remaining requisite service period	2 years 4 months 24 days
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 1,137
Weighted-average remaining requisite service period	2 years 10 months 24 days
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 4,096
Weighted-average remaining requisite service period	3 years
Accrued compensation and benefits expenses | Service Period | Liability Classified Award | Cash-Settled Award | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability associated with RSUs	$ 18,577	$ 21,902
2020 Acquisitions | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining unrecognized stock-based compensation cost	$ 698
Weighted-average remaining requisite service period	2 years 3 months 18 days
Estimated future operating results, period	2 years
Awards vesting period	3 years
Award value	$ 11,527

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	14.00%	16.20%	12.60%	13.10%
Excess tax benefit	$ 9,165	$ 4,228	$ 28,991	$ 20,482

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator for basic and diluted earnings per share:
Net income	$ 89,432	$ 66,624	$ 85,565	$ 67,002	$ 58,777	$ 60,754	$ 241,621	$ 186,533
Numerator for basic and diluted earnings per share	$ 89,432			$ 67,002			$ 241,621	$ 186,533
Denominator:
Weighted average common shares for basic earnings per share	55,883,879			54,877,666			55,624,727	54,603,903
Net effect of dilutive stock options, restricted stock units and restricted stock awards	2,732,227			2,966,689			2,716,451	2,963,436
Weighted average common shares for diluted earnings per share	58,616,106			57,844,355			58,341,178	57,567,339
Net income per share:
Basic (in dollars per share)	$ 1.60			$ 1.22			$ 4.34	$ 3.42
Diluted (in dollars per share)	$ 1.53			$ 1.16			$ 4.14	$ 3.24
Anti-dilutive options not included in the calculation (in shares)	2,627			143,617			40,276	112,757

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Building Acquisition Commitments) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Office Space Purchase Commitment | Ukraine
Other Commitments [Line Items]
Total commitment amount	$ 36,900

SEGMENTS INFORMATION (Revenues

SEGMENTS INFORMATION (Revenues from External Customers and Operating Profit Before Unallocated Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 652,243	$ 588,103	$ 1,935,985	$ 1,661,023
Segment operating profit	96,396	80,565	267,331	218,105
North America
Segment Reporting Information [Line Items]
Revenues	391,605	358,987	1,167,536	1,000,701
Segment operating profit	87,272	79,310	248,951	213,114
Europe
Segment Reporting Information [Line Items]
Revenues	231,418	204,952	695,056	596,378
Segment operating profit	43,018	27,550	109,223	87,014
Russia
Segment Reporting Information [Line Items]
Revenues	29,220	24,164	73,393	63,944
Segment operating profit	2,958	5,524	(2,168)	11,765
Operating Segments
Segment Reporting Information [Line Items]
Segment operating profit	$ 133,248	$ 112,384	$ 356,006	$ 311,893

SEGMENTS INFORMATION (Major Cus

SEGMENTS INFORMATION (Major Customers) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue, Segment Benchmark | Customer Concentration Risk | Operating Segments
Revenue, Major Customer [Line Items]
Number of customers	0	0	0	0

SEGMENTS INFORMATION (Reconcili

SEGMENTS INFORMATION (Reconciliation of Segment Operating Profit to Consolidated Income Before Provision for Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment operating profit	$ 96,396	$ 80,565	$ 267,331	$ 218,105
Stock-based compensation expense	23,474	15,471	54,794	53,024
Interest and other income, net	1,672	2,509	5,875	6,775
Foreign exchange gain/(loss)	5,896	(3,105)	3,253	(10,151)
Income before provision for income taxes	103,964	79,969	276,459	214,729
Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment operating profit	133,248	112,384	356,006	311,893
Unallocated Amounts
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Stock-based compensation expense	(23,474)	(15,471)	(54,794)	(53,024)
Amortization of intangibles assets	(3,086)	(2,554)	(9,215)	(7,293)
Other acquisition-related expenses	(243)	(1,144)	(859)	(2,505)
Other unallocated expenses	$ (10,049)	$ (12,650)	$ (23,807)	$ (30,966)

SEGMENTS INFORMATION (Physical

SEGMENTS INFORMATION (Physical Location and Values of Long-Lived Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 163,689	$ 165,259
Belarus
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	72,507	75,984
Ukraine
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	30,142	24,652
United States
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	16,329	15,637
Russia
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	13,686	17,980
India
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	6,349	7,443
Poland
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	5,032	5,029
Hungary
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	4,820	5,201
Spain
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,685	1,106
China
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,556	3,036
Mexico
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,431	2,353
Other
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 7,152	$ 6,838

SEGMENTS INFORMATION (Revenue_2

SEGMENTS INFORMATION (Revenues by Customer Location) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 652,243	$ 588,103	$ 1,935,985	$ 1,661,023
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	371,366	340,803	1,106,459	959,471
United Kingdom
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	77,519	74,992	251,928	209,773
Switzerland
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	50,399	38,781	144,158	110,378
Netherlands
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	28,827	22,161	81,973	63,816
Russia
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	27,963	23,668	69,372	62,020
Germany
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	22,172	20,940	62,163	59,716
Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	18,219	17,582	52,724	50,339
Other locations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 55,778	$ 49,176	$ 167,208	$ 145,510