EPAM Systems (EPAM) 10-Q 7 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
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		54,984,738
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 853,241	$ 770,560
Accounts receivable, net of allowance of $1,519 and $1,557, respectively	339,112	297,685
Unbilled revenues	142,949	104,652
Prepaid expenses and other current assets	29,390	26,171
Total current assets	1,364,692	1,199,068
Property and equipment, net	115,321	102,646
Operating lease right-of-use assets	207,145	0
Intangible assets, net	56,537	57,065
Goodwill	186,299	166,832
Deferred tax assets	75,071	69,983
Other noncurrent assets	35,098	16,208
Total assets	2,040,163	1,611,802
Current liabilities
Accounts payable	6,896	7,444
Accrued expenses and other current liabilities	128,639	127,937
Due to employees	63,536	49,683
Deferred compensation due to employees	13,427	9,920
Taxes payable, current	47,548	67,845
Operating lease liabilities, current	51,424	0
Total current liabilities	311,470	262,829
Long-term debt	25,000	25,031
Taxes payable, noncurrent	43,738	43,685
Operating lease liabilities, noncurrent	153,980	0
Other noncurrent liabilities	13,858	17,661
Total liabilities	548,046	349,206
Commitments and contingencies (Note 12)
Stockholders’ equity
Common stock, $0.001 par value; 160,000,000 authorized; 54,968,833 and 54,099,927 shares issued, 54,949,098 and 54,080,192 shares outstanding at September 30, 2019 and December 31, 2018, respectively	55	54
Additional paid-in capital	589,764	544,700
Retained earnings	946,066	759,533
Treasury stock	(177)	(177)
Accumulated other comprehensive loss	(43,591)	(41,514)
Total stockholders’ equity	1,492,117	1,262,596
Total liabilities and stockholders’ equity	$ 2,040,163	$ 1,611,802

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets
Accounts receivable allowance	$ 1,519	$ 1,557
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)	54,968,833	54,099,927
Common stock, shares outstanding (in shares)	54,949,098	54,080,192

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenues	$ 588,103	$ 468,186	$ 1,661,023	$ 1,337,981
Operating expenses:
Cost of revenues (exclusive of depreciation and amortization)	377,525	301,081	1,078,129	867,890
Selling, general and administrative expenses	118,886	93,226	332,434	276,140
Depreciation and amortization expense	11,127	9,319	32,355	26,457
Income from operations	80,565	64,560	218,105	167,494
Interest and other income, net	2,509	1,941	6,775	2,442
Foreign exchange (loss)/gain	(3,105)	(514)	(10,151)	1,069
Income before provision for/(benefit from) income taxes	79,969	65,987	214,729	171,005
Provision for/(benefit from) income taxes	12,967	369	28,196	(9,286)
Net income	67,002	65,618	186,533	180,291
Foreign currency translation adjustments, net of tax	(10,114)	(2,118)	(4,551)	(14,643)
Unrealized (loss)/gain on cash-flow hedging instruments, net of tax	(2,163)	(74)	2,474	(2,081)
Comprehensive income	$ 54,725	$ 63,426	$ 184,456	$ 163,567
Net income per share:
Basic (in dollars per share)	$ 1.22	$ 1.22	$ 3.42	$ 3.37
Diluted (in dollars per share)	$ 1.16	$ 1.15	$ 3.24	$ 3.19
Shares used in calculation of net income per share:
Basic (in shares)	54,877,666	53,851,865	54,603,903	53,485,339
Diluted (in shares)	57,844,355	56,962,867	57,567,339	56,599,638

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS’ EQUITY Statement - USD ($) $ in Thousands	Total	Common Stock	Common StockRestricted Stock Units (RSUs)	Common StockRestricted Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Balance, beginning of period (in shares) at Dec. 31, 2017		52,983,685
Balance, beginning of period at Dec. 31, 2017	$ 974,947	$ 53			$ 473,874	$ 518,820		$ (17,623)
Treasury stock, beginning of period (in shares) at Dec. 31, 2017							19,735
Treasury stock, beginning period at Dec. 31, 2017							$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)			186,327
Stock units withheld for employee taxes	(6,986)				(6,986)
Stock units withheld for employee taxes (in shares)			(61,950)
Proceeds from stock options exercises	7,649				7,649
Proceeds from stock options exercises (in shares)		198,936
Stock-based compensation expense	11,485				11,485
Foreign currency translation adjustments, net of tax	3,309							3,309
Change in unrealized gains and loss on cash-flow hedges, net of tax	69							69
Cumulative effect of the adoption of ASU | ASU 2014-09	457					457
Net income	64,418					64,418
Balance, end of period (in shares) at Mar. 31, 2018		53,306,998
Balance, end of period at Mar. 31, 2018	1,055,348	$ 53			486,022	583,695		(14,245)
Treasury stock, end of period (in shares) at Mar. 31, 2018							19,735
Treasury stock, end of period at Mar. 31, 2018							$ (177)
Balance, beginning of period (in shares) at Dec. 31, 2017		52,983,685
Balance, beginning of period at Dec. 31, 2017	974,947	$ 53			473,874	518,820		(17,623)
Treasury stock, beginning of period (in shares) at Dec. 31, 2017							19,735
Treasury stock, beginning period at Dec. 31, 2017							$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Net income	180,291
Balance, end of period (in shares) at Sep. 30, 2018		53,991,844
Balance, end of period at Sep. 30, 2018	1,195,935	$ 54			530,837	699,568		(34,347)
Treasury stock, end of period (in shares) at Sep. 30, 2018							19,735
Treasury stock, end of period at Sep. 30, 2018							$ (177)
Balance, beginning of period (in shares) at Mar. 31, 2018		53,306,998
Balance, beginning of period at Mar. 31, 2018	1,055,348	$ 53			486,022	583,695		(14,245)
Treasury stock, beginning of period (in shares) at Mar. 31, 2018							19,735
Treasury stock, beginning period at Mar. 31, 2018							$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)			12,348
Stock units withheld for employee taxes	(224)				(224)
Stock units withheld for employee taxes (in shares)			(1,942)
Proceeds from stock options exercises	14,648	$ 1			14,647
Proceeds from stock options exercises (in shares)		367,863
Stock-based compensation expense	10,686				10,686
Foreign currency translation adjustments, net of tax	(15,834)							(15,834)
Change in unrealized gains and loss on cash-flow hedges, net of tax	(2,076)							(2,076)
Net income	50,255					50,255
Balance, end of period (in shares) at Jun. 30, 2018		53,685,267
Balance, end of period at Jun. 30, 2018	1,112,803	$ 54			511,131	633,950		(32,155)
Treasury stock, end of period (in shares) at Jun. 30, 2018							19,735
Treasury stock, end of period at Jun. 30, 2018							$ (177)
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures [Abstract]
Stock units vested (in shares)			12,694
Stock units withheld for employee taxes	(349)				(349)
Stock units withheld for employee taxes (in shares)			(2,683)
Proceeds from stock options exercises	9,561				9,561
Proceeds from stock options exercises (in shares)		296,566
Stock-based compensation expense	10,494				10,494
Foreign currency translation adjustments, net of tax	(2,118)							(2,118)
Change in unrealized gains and loss on cash-flow hedges, net of tax	(74)							(74)
Net income	65,618					65,618
Balance, end of period (in shares) at Sep. 30, 2018		53,991,844
Balance, end of period at Sep. 30, 2018	$ 1,195,935	$ 54			530,837	699,568		(34,347)
Treasury stock, end of period (in shares) at Sep. 30, 2018							19,735
Treasury stock, end of period at Sep. 30, 2018							$ (177)
Balance, beginning of period (in shares) at Dec. 31, 2018	54,080,192	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 loss on cash-flow hedges, 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	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]
Net income	$ 186,533
Balance, end of period (in shares) at Sep. 30, 2019	54,949,098	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 loss on cash-flow hedges, 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 loss on cash-flow hedges, 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	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)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 186,533	$ 180,291
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	32,355	26,457
Operating lease right-of-use assets amortization expense	40,203	0
Bad debt expense	133	1,765
Deferred taxes	(3,105)	(36,372)
Stock-based compensation expense	53,024	46,736
Other	7,522	(3,434)
Changes in assets and liabilities:
Accounts receivable	(40,753)	(16,258)
Unbilled revenues	(37,080)	(41,544)
Prepaid expenses and other assets	237	(1,765)
Accounts payable	(1,844)	1,574
Accrued expenses and other liabilities	(3,092)	9,625
Operating lease liabilities	(39,230)	0
Due to employees	(5,627)	4,009
Taxes payable	(26,410)	(1,996)
Net cash provided by operating activities	162,866	169,088
Cash flows from investing activities:
Purchases of property and equipment	(52,295)	(27,465)
Acquisition of businesses, net of cash acquired (Note 2)	(28,655)	(50,264)
Other investing activities, net	(6,632)	(104)
Net cash used in investing activities	(87,582)	(77,833)
Cash flows from financing activities:
Proceeds from stock option exercises	28,798	32,007
Payments of withholding taxes related to net share settlements of restricted stock units	(14,521)	(7,068)
Repayment of debt	(7)	(3,485)
Acquisition of businesses, contingent consideration	(1,104)	0
Other financing activities, net	(19)	(603)
Net cash provided by financing activities	13,147	20,851
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(5,753)	(8,660)
Net increase in cash, cash equivalents and restricted cash	82,678	103,446
Cash, cash equivalents and restricted cash, beginning of period	771,711	582,855
Cash, cash equivalents and restricted cash, end of period	$ 854,389	$ 686,301

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENT OF CASH FLOW (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 853,241	$ 770,560
Total restricted cash	1,148	1,151
Total cash, cash equivalents, restricted cash and restricted cash equivalents	854,389	771,711
Prepaid expenses and other current assets
Restricted cash	14	14
Other noncurrent assets
Restricted cash	$ 1,134	$ 1,137

BUSINESS AND SUMMARY OF SIGNIFI

BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2019
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, PA. 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 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, 2018 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. 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. Leases — In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, Leases (“Topic 842”). The standard supersedes previously existing lease guidance (Topic 840) and requires entities to recognize all leases, with the exception of leases with a term of twelve months or less, on the balance sheet as right-of-use assets (“RoU Assets”) and lease liabilities. The guidance also changes disclosure requirements with a focus on providing information that will enable users of financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. The Company adopted Topic 842, effective January 1, 2019, using the optional transition approach, which allows the Company to apply the provisions of the standard at the effective date without adjusting the comparable periods and carry forward disclosures under previously existing guidance for those periods presented within the Company’s financial statements. The Company determines if an arrangement is a lease or contains a lease at inception. The Company performs an assessment and classifies the lease as either an operating lease or a financing lease at the lease commencement date with a right-of-use asset and a lease liability recognized in the statement of financial position under both classifications. The Company does not have finance leases that are material to the Company’s condensed consolidated financial statements. Lease liabilities are initially measured at the present value of lease payments not yet paid. The present value is determined by applying the readily determinable rate implicit in the lease or, if not available, the incremental borrowing rate of the lessee. The Company determines the incremental borrowing rate of the lessee on a lease-by-lease basis by developing an estimated centralized U.S. dollar borrowing rate for a fully collateralized obligation with a term similar to the lease term, and adjusts the rate to reflect the incremental risk associated with the currency in which the lease is denominated. Lease agreements of the Company may include options to extend or terminate the lease and the Company includes such options in the lease term when it is reasonably certain that the Company will exercise that option. RoU Assets are recognized based on the initial measurement of the lease liabilities plus initial direct costs less lease incentives and, according to the guidance for long-lived assets, RoU Assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Lease expense for operating leases is recognized on a straight-line basis over the lease term. The Company elected a practical expedient to account for lease and non-lease components together as a single lease component. The Company also elected the short-term lease recognition exemption for all classes of lease assets with an original term of twelve months or less. As part of the transition, the Company elected a package of practical expedients allowing it to carry forward historical accounting for any expired or existing contracts that are or contain lease contracts, including classification of such contracts and initial direct costs associated with them. The adoption of Topic 842 on January 1, 2019 resulted in the recognition of RoU Assets for operating leases of $177,597 and operating lease liabilities of $173,863 . The adoption of Topic 842 did not have a material impact on the condensed consolidated statement of income and comprehensive income, condensed consolidated statement of changes in stockholders’ equity or the condensed consolidated statement of cash flows. See Note 6 “Leases” in the condensed consolidated interim financial statements for additional information regarding leases. 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. Unless otherwise discussed below, 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. Measurement of Credit Losses on Financial Instruments — Effective January 1, 2020, the Company will be required to adopt the amended guidance of FASB ASC Topic 326, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , (with early adoption permitted effective January 1, 2019.) The amendments in this update change how companies measure and recognize credit impairment for many financial assets. The new expected credit loss model will require 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. Entities are required to adopt the standard using a modified-retrospective approach through a cumulative effect adjustment to retained earnings as of the beginning of the period of adoption. The Company has not yet completed its assessment of the impact of the new guidance on its consolidated financial statements and will adopt the standard on January 1, 2020.

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
ACQUISITIONS	ACQUISITIONS Continuum — On March 15, 2018 , the Company acquired all of the outstanding equity of Continuum Innovation LLC together with its subsidiaries (“Continuum”) to enhance the Company’s consulting capabilities as well as its digital and service design practices. Continuum, headquartered in Boston with offices located in Milan, Seoul, and Shanghai, focuses on four practices including strategy, physical and digital design, technology and its Made Real Lab. The acquisition of Continuum added approximately 125 design consultants to the Company’s headcount. In connection with the Continuum acquisition, the Company paid $52,515 of cash and committed to making a cash earnout payment with a maximum amount payable of $3,135 , subject to attainment of specified performance targets in the 12 months after the acquisition date. Think — On November 1, 2018 , the Company acquired all of the equity interests of Think Limited (“Think”), a digital transformation agency headquartered in London, UK. This acquisition was intended to strengthen EPAM’s digital and organizational consulting capabilities in the UK and Western European markets and enhance the Company’s global product and design offerings. In connection with the Think acquisition, the Company paid $26,254 at closing and committed to making a cash earnout payment with a maximum amount payable of $8,156 , subject to attainment of specified performance targets in the 12 months after the acquisition date. During the three months ended September 30, 2019, the Company received $271 as a true-up payment which reduced the purchase price. test IO — On April 30, 2019 , the Company acquired 100% of the equity interests of a crowdtesting company, test IO GmbH, and its subsidiary (“test IO”). In connection with the test IO acquisition, the Company paid $17,323 of cash. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed as of the date of acquisition and updated for any changes as of September 30, 2019 for each respective acquisition: Continuum Think test IO Cash and cash equivalents $ 2,251 $ 2,344 $ 668 Accounts receivable 6,676 2,259 727 Unbilled revenues 2,463 284 — Prepaid expenses and other current assets 936 609 96 Goodwill 26,617 22,211 12,084 Intangible assets 14,450 6,882 6,219 Property and equipment and other noncurrent assets 8,902 642 154 Total assets acquired $ 62,295 $ 35,231 $ 19,948 Accounts payable, accrued expenses and other current liabilities $ 2,745 $ 2,205 $ 877 Due to employees 1,001 13 42 Long-term debt 3,220 — — Other noncurrent liabilities 490 1,040 1,706 Total liabilities assumed $ 7,456 $ 3,258 $ 2,625 Net assets acquired $ 54,839 $ 31,973 $ 17,323 During 2018, the Company adjusted initially recognized intangible assets acquired with Continuum and their useful lives as well as recognized an additional intangible asset in the form of a favorable lease, removed a noncurrent liability associated with an initially recognized unfavorable lease and revised the initial fair value of contingent consideration. The Company also finalized a working capital adjustment that resulted in cash collection in the amount of $76 reducing the original amount of the net assets acquired. These adjustments resulted in a corresponding decrease to the originally recognized value of acquired goodwill. During the first quarter of 2019, the Company finalized the fair value of the assets acquired and liabilities assumed in the acquisition of Continuum and no additional adjustments were recorded. For the acquisitions of Think and test IO, estimated fair values of the assets acquired and liabilities assumed remain provisional and based on the facts and circumstances that existed as of the acquisition dates. The Company expects to complete the purchase price allocations as soon as practicable but no later than one year from the acquisition dates. During the three months ended September 30, 2019 , the Company recorded purchase price adjustments which reduced the original purchase price for Think by $271 , with a corresponding decrease to the originally recognized value of acquired goodwill. During the three months ended September 30, 2019 , the Company recorded purchase price adjustments which increased the original purchase price for test IO and adjusted related working capital accounts increasing the original amount of the net assets acquired by $119 . In addition for the test IO acquisition, the Company reduced the value of acquired intangible assets by $145 with a corresponding increase to goodwill. The following table presents the estimated fair values and useful lives of intangible assets acquired from Continuum, Think, and test IO as of the date of acquisition and updated for any changes as of September 30, 2019 for each respective acquisition: Continuum Think test IO Weighted Average Useful Life (in years) Amount Weighted Average Useful Life (in years) Amount Weighted Average Useful Life (in years) Amount Customer relationships 6.5 $ 5,800 7 $ 6,117 7 $ 2,456 Favorable lease 11.2 5,500 — — — — Software — — — — 6 3,461 Contract royalties 8 1,900 — — — — Trade names 5 1,250 5 765 4 302 Total $ 14,450 $ 6,882 $ 6,219 In connection with the adoption of Topic 842, effective January 1, 2019, the Company reclassified the favorable lease intangible asset to Operating lease right-of-use assets. The goodwill recognized as a result of the acquisitions is attributable primarily to strategic and synergistic opportunities related to the consulting and design businesses, the assembled workforces acquired and other factors. The goodwill acquired as a result of the Continuum acquisition is expected to be deductible for income tax purposes while the goodwill acquired as a result of the Think and test IO acquisitions is not expected to be deductible for income tax purposes. Revenues generated by test IO, acquired on April 30, 2019, totaled $1,692 and $2,606 during the three and nine months ended September 30, 2019 , respectively. Pro forma results of operations have not been presented because the effect of the acquisitions on the Company’s condensed consolidated financial statements was not material individually or in the aggregate. Other 2019 Acquisitions — During the three months ended September 30, 2019, the Company completed three additional acquisitions with an aggregate cash purchase price of $14,080 and committed to making cash earnout payments with a maximum amount payable of $3,000 subject to attainment of specified performance targets in the 12 months and 24 months after the respective acquisition dates. These acquisitions increased EPAM’s educational services and platform offerings and expanded the Company’s geographical reach. Revenues generated by the Other 2019 Acquisitions totaled $3,009 during both the three and nine months ended September 30, 2019 . Pro forma results of operations have not been presented because the effect of the acquisitions on the Company’s condensed consolidated financial statements was not material individually or in the aggregate.

GOODWILL

GOODWILL	9 Months Ended
	Sep. 30, 2019
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, 2019 $ 103,542 $ 63,290 $ — $ 166,832 test IO acquisition 3,310 8,775 — 12,085 Other 2019 acquisitions 6,710 2,028 767 9,505 Think purchase accounting adjustments — (258 ) — (258 ) Effect of net foreign currency exchange rate changes (145 ) (1,714 ) (6 ) (1,865 ) Balance as of September 30, 2019 $ 113,417 $ 72,121 $ 761 $ 186,299 There were no accumulated impairment losses in the North America or Europe reportable segments as of September 30, 2019 or December 31, 2018 . The Russia segment had accumulated goodwill impairment losses of $2,241 as of September 30, 2019 and December 31, 2018 .

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018: As of September 30, 2019 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 1,189 $ — $ 1,189 $ — Total assets measured at fair value on a recurring basis $ 1,189 $ — $ 1,189 $ — Foreign exchange derivative liabilities $ 1,291 $ — $ 1,291 $ — Contingent consideration 9,572 — — 9,572 Total liabilities measured at fair value on a recurring basis $ 10,863 $ — $ 1,291 $ 9,572 As of December 31, 2018 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 181 $ — $ 181 $ — Total assets measured at fair value on a recurring basis $ 181 $ — $ 181 $ — Foreign exchange derivative liabilities $ 3,475 $ — $ 3,475 $ — Contingent consideration 7,468 — — 7,468 Total liabilities measured at fair value on a recurring basis $ 10,943 $ — $ 3,475 $ 7,468 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 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 business 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 agreement and adjusted those estimates to reflect the probability of their achievement. Those estimated future payments were then discounted to present value using a rate based on the weighted-average cost of capital of guideline companies. 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 consolidated statement of income and comprehensive income. In connection with the Continuum acquisition, the Company committed to making a cash earnout payment subject to attainment of specified performance targets in the 12 months after the acquisition date. As of the acquisition date, the Company recorded a $2,400 contingent consideration liability related to this earnout payment and, subsequently, reduced this liability by $900 during the third quarter of 2018 and $396 during the second quarter of 2019 due to the change in its fair value. The Company extinguished the earnout obligation during the second quarter of 2019 by paying $1,104 in cash. In connection with the Think acquisition, the Company committed to making a cash earnout payment subject to attainment of specified performance targets in the 12 months after the acquisition date. As of the acquisition date, the Company recorded a $5,990 liability related to this earnout payment as contingent consideration and, subsequently, increased this liability by $1,752 during the second quarter of 2019 due to the change in its fair value. In connection with the Other 2019 Acquisitions, the Company committed to making cash earnout payments subject to attainment of specified performance targets in the 12 months and 24 months after the respective acquisition dates. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. A reconciliation of the beginning and ending balances of Level 3 acquisition-related contractual contingent liabilities using significant unobservable inputs for the nine months ended September 30, 2019 is as follows: Amount Contingent consideration liabilities as of January 1, 2019 $ 7,468 Payment of contingent consideration (1,104 ) Acquisition date fair value of contractual contingent liabilities — Other 2019 Acquisitions (Note 2) 2,100 Changes in fair value of contingent consideration included in Interest and other income, net 1,356 Effect of net foreign currency exchange rate changes (248 ) Contingent consideration liabilities as of September 30, 2019 $ 9,572 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 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, 2019 Financial Assets: Cash and cash equivalents $ 853,241 $ 853,241 $ 853,241 $ — $ — Restricted cash $ 1,148 $ 1,148 $ 1,148 $ — $ — Employee loans $ 2,608 $ 2,608 $ — $ — $ 2,608 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,017 $ 25,017 $ — $ 25,017 $ — Fair Value Hierarchy Balance Estimated Fair Value Level 1 Level 2 Level 3 December 31, 2018 Financial Assets: Cash and cash equivalents $ 770,560 $ 770,560 $ 770,560 $ — $ — Restricted cash $ 1,151 $ 1,151 $ 1,151 $ — $ — Employee loans $ 3,525 $ 3,525 $ — $ — $ 3,525 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,020 $ 25,020 $ — $ 25,020 $ —

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2019
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, 2019 , 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, 2019 and December 31, 2018 were as follows: As of September 30, 2019 As of December 31, 2018 Balance Sheet Classification Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives Foreign exchange forward contracts - Designated as hedging instruments Prepaid expenses and other current assets $ 1,189 $ 181 Accrued expenses and other current liabilities $ 1,291 $ 3,475 The Company records changes in the fair value of its cash flow hedges in accumulated other comprehensive loss in the 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, 2019 and 2018 were as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 Foreign exchange forward contracts - Designated as hedging instruments: Change in fair value recognized in accumulated other comprehensive loss $ (2,791 ) $ (86 ) $ 3,192 $ (2,692 ) Net gain/(loss) reclassified from accumulated other comprehensive loss into cost of revenues (exclusive of depreciation and amortization) $ 848 $ (1,604 ) $ 738 $ (2,541 ) Foreign exchange forward contracts - Not designated as hedging instruments: Net gain recognized in foreign exchange (loss)/gain $ — $ — $ — $ 44

LEASES

LEASES	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
LEASES	ny 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 RoU 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 11.6 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 subleases a portion of its office space to third parties. During the three and nine months ended September 30, 2019 , the components of lease expense were as follows: Income Statement Classification Three Months Ended Nine Months Ended Operating lease cost Selling, general and administrative expenses $ 16,210 $ 45,125 Variable lease cost Selling, general and administrative expenses 2,439 6,535 Short-term lease cost Selling, general and administrative expenses 1,085 2,989 Sublease income Interest and other income, net (664 ) (1,596 ) Total lease cost $ 19,070 $ 53,053 Supplemental cash flow information related to leases was as follows: Three Months Ended Nine Months Ended Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 14,709 $ 43,510 Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 14,251 $ 67,798 Non-cash net increase due to lease modifications: Operating lease right-of-use assets $ 3,233 $ 6,383 Operating lease liabilities $ 3,199 $ 6,451 Weighted average remaining lease term and discount rate as of September 30, 2019 were as follows: As of September 30, 2019 Weighted average remaining lease term, in years: Operating leases 5.9 Weighted average discount rate: Operating leases 3.8 % As of September 30, 2019 , operating lease liabilities will mature as follows: Year ending December 31, Lease Payments 2019 (excluding nine months ended September 30, 2019) $ 15,442 2020 55,258 2021 44,896 2022 28,396 2023 20,915 Thereafter 63,793 Total lease payments 228,700 Less: imputed interest (23,295 ) Total $ 205,405 There were no lease agreements that contained material restrictive covenants or material residual value guarantees as of September 30, 2019 . There were no lease agreements signed with related parties as of September 30, 2019 . As of September 30, 2019 , the Company had committed to payments of $69,683 related to operating lease agreements that had not yet commenced. These operating leases will commence during various dates during 2019 through 2020 with lease terms ranging from 1.2 to 11.6 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, 2019
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, 2019 , 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, 2019 , 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 3.1 % 3.5 % Irrevocable standby letters of credit $ 295 $ 382 Available borrowing capacity $ 274,705 $ 274,618 Current maximum borrowing capacity $ 300,000 $ 300,000

REVENUES

REVENUES	9 Months Ended
	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
REVENUES	REVENUES Disaggregation of Revenues The Company’s revenues are sourced from four geographic markets: North America, Europe, CIS and APAC. CIS includes revenues from customers in Belarus, Kazakhstan, Russia and Ukraine. APAC, which stands for Asia Pacific, includes revenues from customers in East Asia, Southeast Asia and Australia. 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, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 349,875 $ 8,484 $ 42 $ 358,401 $ — $ 358,401 Europe 6,756 182,621 23 189,400 (88 ) 189,312 CIS 2,349 53 24,099 26,501 — 26,501 APAC 7 13,965 — 13,972 (83 ) 13,889 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 976,841 $ 32,928 $ 74 $ 1,009,843 $ (2 ) $ 1,009,841 Europe 16,736 523,487 263 540,486 (321 ) 540,165 CIS 6,093 66 63,608 69,767 (1 ) 69,766 APAC 1,045 40,317 — 41,362 (111 ) 41,251 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 271,551 $ 12,536 $ 17 $ 284,104 $ (27 ) $ 284,077 Europe 5,408 146,990 3 152,401 (166 ) 152,235 CIS 2,208 142 16,184 18,534 — 18,534 APAC 1,671 11,814 4 13,489 (149 ) 13,340 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 747,894 $ 40,074 $ 46 $ 788,014 $ (40 ) $ 787,974 Europe 11,234 444,468 45 455,747 (623 ) 455,124 CIS 6,300 233 53,192 59,725 — 59,725 APAC 3,709 31,545 91 35,345 (187 ) 35,158 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 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, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 50,510 $ 61,189 $ 18,760 $ 130,459 $ (122 ) $ 130,337 Travel & Consumer 51,476 57,780 3,171 112,427 (45 ) 112,382 Software & Hi-Tech 90,880 16,952 552 108,384 — 108,384 Business Information & Media 65,153 40,624 22 105,799 — 105,799 Life Sciences & Healthcare 60,049 6,713 7 66,769 — 66,769 Emerging Verticals 40,919 21,865 1,652 64,436 (4 ) 64,432 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 132,435 $ 182,143 $ 49,801 $ 364,379 $ (376 ) $ 364,003 Travel & Consumer 146,654 169,157 8,056 323,867 (45 ) 323,822 Software & Hi-Tech 255,601 56,764 1,470 313,835 (2 ) 313,833 Business Information & Media 189,854 108,852 266 298,972 (6 ) 298,966 Life Sciences & Healthcare 164,492 16,176 73 180,741 — 180,741 Emerging Verticals 111,679 63,706 4,279 179,664 (6 ) 179,658 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 30,488 $ 61,713 $ 12,786 $ 104,987 $ (189 ) $ 104,798 Travel & Consumer 45,690 53,634 1,891 101,215 (122 ) 101,093 Software & Hi-Tech 68,572 19,035 569 88,176 — 88,176 Business Information & Media 64,152 17,650 — 81,802 — 81,802 Life Sciences & Healthcare 39,550 5,078 12 44,640 (31 ) 44,609 Emerging Verticals 32,386 14,372 950 47,708 — 47,708 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 79,176 $ 190,027 $ 43,102 $ 312,305 $ (697 ) $ 311,608 Travel & Consumer 133,481 155,208 5,356 294,045 (122 ) 293,923 Software & Hi-Tech 193,672 59,186 1,957 254,815 — 254,815 Business Information & Media 181,021 54,637 — 235,658 — 235,658 Life Sciences & Healthcare 99,893 15,550 12 115,455 (31 ) 115,424 Emerging Verticals 81,894 41,712 2,947 126,553 — 126,553 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 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, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 322,573 $ 171,261 $ 13,815 $ 507,649 $ — $ 507,649 Fixed-price 35,273 33,093 10,304 78,670 — 78,670 Licensing 883 149 9 1,041 — 1,041 Other revenues 258 620 36 914 (171 ) 743 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 907,624 $ 507,055 $ 37,134 $ 1,451,813 $ — $ 1,451,813 Fixed-price 89,694 87,543 26,534 203,771 — 203,771 Licensing 2,343 689 211 3,243 — 3,243 Other revenues 1,054 1,511 66 2,631 (435 ) 2,196 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 256,549 $ 155,797 $ 9,441 $ 421,787 $ — $ 421,787 Fixed-price 23,241 15,001 6,759 45,001 — 45,001 Licensing 798 173 1 972 — 972 Other revenues 250 511 7 768 (342 ) 426 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 704,612 $ 471,900 $ 29,302 $ 1,205,814 $ — $ 1,205,814 Fixed-price 61,716 42,035 24,038 127,789 — 127,789 Licensing 2,098 1,119 12 3,229 — 3,229 Other revenues 711 1,266 22 1,999 (850 ) 1,149 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 Timing of Revenue Recognition The following tables present the timing of revenue recognition for the periods indicated: Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 561 $ 290 $ 54 $ 905 $ (171 ) $ 734 Transferred over time 358,426 204,833 24,110 587,369 — 587,369 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 1,185 $ 692 $ 55 $ 1,932 $ (435 ) $ 1,497 Transferred over time 999,530 596,106 63,890 1,659,526 — 1,659,526 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 194 $ 289 $ — $ 483 $ (342 ) $ 141 Transferred over time 280,644 171,193 16,208 468,045 — 468,045 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 832 $ 1,351 $ 10 $ 2,193 $ (850 ) $ 1,343 Transferred over time 768,305 514,969 53,364 1,336,638 — 1,336,638 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 During the three and nine months ended September 30, 2019 the Company recognized $4,915 and $7,039 of revenues, respectively, from performance obligations satisfied in previous periods compared to $3,610 and $6,627 during the three and nine months ended September 30, 2018, 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, 2019 . 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 $ 12,226 $ 2,774 $ 140 $ — $ 15,140 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 Unbilled revenues $ 24,870 $ 13,522 Contract liabilities included in Accrued expenses and other current liabilities $ 4,954 $ 4,558 Contract liabilities included in Other noncurrent liabilities $ 1 $ 224 Contract assets included in Unbilled revenues are recorded when services have been provided but the Company does not have an unconditional right to receive consideration. The Company recognizes an impairment loss when the contract carrying amount is greater than the remaining consideration expected less the remaining costs of providing services. Contract assets have increased from December 31, 2018 primarily due to new contracts entered into in the nine months ended September 30, 2019 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 increased from December 31, 2018 primarily due to the acquisition of test IO on April 30, 2019. During the three and nine months ended September 30, 2019 , the Company recognized $140 and $3,801 , respectively, of revenues 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, 2019
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 2019 2018 2019 2018 Cost of revenues (exclusive of depreciation and amortization) $ 7,580 $ 7,492 $ 27,841 $ 22,835 Selling, general and administrative expenses 7,891 7,838 25,183 23,901 Total $ 15,471 $ 15,330 $ 53,024 $ 46,736 Stock Options Stock option activity under the Company’s plans is set forth below: Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Term (in years) Options outstanding at January 1, 2019 4,082,944 $ 44.54 Options granted 131,849 $ 169.13 Options modified 17,871 $ 163.55 Options exercised (668,339 ) $ 43.09 Options forfeited/cancelled (10,701 ) $ 97.83 Options outstanding at September 30, 2019 3,553,624 $ 49.87 $ 470,672 4.9 Options vested and exercisable at September 30, 2019 3,129,141 $ 41.01 $ 442,179 4.5 Options expected to vest at September 30, 2019 397,070 $ 114.20 $ 27,050 8.3 As of September 30, 2019 , $13,619 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, 2019 : 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 Fair Value Per Share Number of Shares Weighted Average Grant Date Fair Value Per Share Number of Shares Weighted Average Grant Date Fair Value Per Share Unvested service-based awards outstanding at January 1, 2019 793 $ 63.10 797,903 $ 92.13 302,967 $ 83.99 Awards granted 9,394 $ 167.18 282,628 $ 170.25 55,912 $ 170.12 Awards modified — $ — 6,897 $ 170.74 668 $ 168.36 Awards vested (396 ) $ 63.10 (273,119 ) $ 86.38 (110,012 ) $ 80.34 Awards forfeited/cancelled — $ — (35,004 ) $ 111.93 (4,856 ) $ 94.73 Unvested service-based awards outstanding at September 30, 2019 9,791 $ 162.96 779,305 $ 122.28 244,679 $ 105.33 As of September 30, 2019 , $1,540 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 2.9 years . During the third quarter of 2019, in connection with one of the Other 2019 Acquisitions, the Company issued 9,394 shares of service-based restricted stock. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. As of September 30, 2019 , $70,990 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 2.7 years . During the first nine months of 2019, 21,933 RSUs were granted in connection with acquisition of businesses. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. As of September 30, 2019 , $28,764 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 2.2 years . During the third quarter of 2019, in connection with one of the Other 2019 Acquisitions, the Company issued 7,280 shares of service-based liability-classified cash-settled RSUs. 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, 2019 and December 31, 2018 , was $13,427 and $9,920 , respectively, and was classified as Deferred compensation due to employees 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, 2019 : Equity-Classified Equity-Settled Restricted Stock Units Equity-Classified Number of Shares Weighted Average Grant Date Fair Value Per Share Number of Weighted Average Grant Date Unvested performance-based awards outstanding at January 1, 2019 29,592 $ 121.75 — $ — Awards granted — $ — 9,393 $ 165.87 Awards modified (29,592 ) $ 121.75 — $ — Unvested performance-based awards outstanding at September 30, 2019 — $ — 9,393 $ 165.87 During the first quarter of 2019, the Company and holders of the unvested performance-based equity-classified RSUs mutually agreed to cancel the performance-based RSU awards and the Company issued service-based stock option and RSU awards with four-year vesting terms to those same recipients. As of September 30, 2019, there is no remaining unrecognized stock-based compensation cost related to performance-based equity-classified RSUs. During the third quarter of 2019, in connection with one of the Other 2019 Acquisitions, the Company issued 9,393 shares of performance-based restricted stock, subject to attainment of specified performance targets in the 12 months and 24 months after the acquisition date. See Note 2 “Acquisitions” in the condensed consolidated interim financial statements for additional information regarding business acquisitions. As of September 30, 2019, $1,041 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 3.9 years

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES In determining its interim provision for/(benefit from) 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, 2019 and 2018 were 16.2% and 0.6% , respectively, and 13.1% and (5.4)% during the nine months ended September 30, 2019 and 2018 , respectively. The Company’s effective tax rates benefited from excess tax benefits recorded upon vesting or exercise of stock-based awards of $4,228 and $6,067 during the three months ended September 30, 2019 and 2018 , respectively, and $20,482 and $16,197 during the nine months ended September 30, 2019 and 2018 , respectively. The interim provision for/(benefit from) income taxes in the three months ended September 30, 2018 was unfavorably impacted by the recognition of $252 of net deferred tax liabilities and the interim provision for/(benefit from) income taxes in the nine months ended September 30, 2018 was favorably impacted by the recognition of $25,088 of net deferred tax assets resulting from the Company’s decision to change the tax status and to classify most of its foreign subsidiaries as disregarded for U.S. income tax purposes. In addition, the interim provision for/(benefit from) income taxes in the three and nine months ended September 30, 2018 was favorably impacted by net provisional reductions of $7,053 and $4,896

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2019
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 2019 2018 2019 2018 Numerator for basic and diluted earnings per share: Net income $ 67,002 $ 65,618 $ 186,533 $ 180,291 Numerator for basic and diluted earnings per share $ 67,002 $ 65,618 $ 186,533 $ 180,291 Denominator: Weighted average common shares for basic earnings per share 54,877,666 53,851,865 54,603,903 53,485,339 Net effect of dilutive stock options, restricted stock units and restricted stock awards 2,966,689 3,111,002 2,963,436 3,114,299 Weighted average common shares for diluted earnings per share 57,844,355 56,962,867 57,567,339 56,599,638 Net income per share: Basic $ 1.22 $ 1.22 $ 3.42 $ 3.37 Diluted $ 1.16 $ 1.15 $ 3.24 $ 3.19 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. 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 157,316 and 121,896 during the three and nine months ended September 30, 2018, respectively.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	fication 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 third quarter of 2019, the Company entered into agreements to purchase office space in Ukraine and Belarus intended to support the delivery centers in those countries. The Belarus agreement is subject to ordinary closing conditions and requires the Company to pay $22,680 in cash including VAT to the sellers, $1,000 of which has been paid as of September 30, 2019 and is classified as Other noncurrent assets in the condensed consolidated balance sheets. The Company completed the acquisition of the Belarus office space on November 1, 2019 . The Ukraine agreement is subject to completion of construction and other ordinary closing conditions and requires the Company to pay approximately $48,900 in cash including VAT to the sellers, $12,000

SEGMENTS INFORMATION

SEGMENTS INFORMATION	9 Months Ended
	Sep. 30, 2019
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 acquisition-related intangible assets, 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/(benefit from) 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. Revenues from external customers and operating profit, before unallocated expenses, by reportable segments for the three and nine months ended September 30, 2019 and 2018 , were as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 Segment revenues: North America $ 358,987 $ 280,838 $ 1,000,715 $ 769,137 Europe 205,123 171,482 596,798 516,320 Russia 24,164 16,208 63,945 53,374 Total segment revenues $ 588,274 $ 468,528 $ 1,661,458 $ 1,338,831 Segment operating profit: North America $ 79,310 $ 60,763 $ 213,114 $ 155,944 Europe 27,550 28,871 87,014 84,329 Russia 5,524 543 11,765 8,211 Total segment operating profit $ 112,384 $ 90,177 $ 311,893 $ 248,484 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, 2019 and 2018 . Accounts receivable and unbilled revenues are generally dispersed across the Company’s customers in proportion to their revenues. There were no customers individually exceeding 10% of total accounts receivable and unbilled revenues as of September 30, 2019 and December 31, 2018 . Reconciliation of segment revenues to consolidated revenues and segment operating profit to consolidated income before provision for/(benefit from) income taxes is presented below: Three Months Ended Nine Months Ended 2019 2018 2019 2018 Total segment revenues $ 588,274 $ 468,528 $ 1,661,458 $ 1,338,831 Other income included in segment revenues (171 ) (342 ) (435 ) (850 ) Revenues $ 588,103 $ 468,186 $ 1,661,023 $ 1,337,981 Total segment operating profit: $ 112,384 $ 90,177 $ 311,893 $ 248,484 Unallocated amounts: Other income included in segment revenues (171 ) (342 ) (435 ) (850 ) Stock-based compensation expense (15,471 ) (15,330 ) (53,024 ) (46,736 ) Non-corporate taxes (3,960 ) (2,063 ) (8,126 ) (7,041 ) Professional fees (1,502 ) (1,420 ) (3,826 ) (4,736 ) Depreciation and amortization expense (2,585 ) (2,011 ) (7,328 ) (5,754 ) Bank charges (645 ) (782 ) (1,937 ) (1,950 ) One-time charges and other acquisition-related expenses (1,142 ) (155 ) (2,503 ) (2,016 ) Other operating expenses (6,343 ) (3,514 ) (16,609 ) (11,907 ) Income from operations 80,565 64,560 218,105 167,494 Interest and other income, net 2,509 1,941 6,775 2,442 Foreign exchange (loss)/gain (3,105 ) (514 ) (10,151 ) 1,069 Income before provision for/(benefit from) income taxes $ 79,969 $ 65,987 $ 214,729 $ 171,005 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 $ 48,521 $ 50,085 Ukraine 16,077 8,433 United States 13,934 13,101 Russia 12,514 9,902 India 6,742 7,019 Hungary 3,329 3,168 China 3,132 2,651 Poland 2,900 2,637 Other 8,172 5,650 Total $ 115,321 $ 102,646 The table below presents information about the Company’s revenues by customer location for the three and nine months ended September 30, 2019 and 2018 : Three Months Ended Nine Months Ended 2019 2018 2019 2018 United States $ 340,803 $ 266,065 $ 959,471 $ 736,579 United Kingdom 74,992 50,482 209,773 152,315 Switzerland 38,781 35,524 110,378 105,396 Russia 23,668 15,609 62,020 51,930 Netherlands 22,161 17,031 63,816 51,934 Germany 20,940 20,732 59,716 60,331 Canada 17,582 18,008 50,339 51,391 Other 49,176 44,735 145,510 128,105 Total $ 588,103 $ 468,186 $ 1,661,023 $ 1,337,981

BUSINESS AND SUMMARY OF SIGNI_2

BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2019
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, PA.
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 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, 2018
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.
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. Leases — In February 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-02, Leases (“Topic 842”). The standard supersedes previously existing lease guidance (Topic 840) and requires entities to recognize all leases, with the exception of leases with a term of twelve months or less, on the balance sheet as right-of-use assets (“RoU Assets”) and lease liabilities. The guidance also changes disclosure requirements with a focus on providing information that will enable users of financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. The Company adopted Topic 842, effective January 1, 2019, using the optional transition approach, which allows the Company to apply the provisions of the standard at the effective date without adjusting the comparable periods and carry forward disclosures under previously existing guidance for those periods presented within the Company’s financial statements. The Company determines if an arrangement is a lease or contains a lease at inception. The Company performs an assessment and classifies the lease as either an operating lease or a financing lease at the lease commencement date with a right-of-use asset and a lease liability recognized in the statement of financial position under both classifications. The Company does not have finance leases that are material to the Company’s condensed consolidated financial statements. Lease liabilities are initially measured at the present value of lease payments not yet paid. The present value is determined by applying the readily determinable rate implicit in the lease or, if not available, the incremental borrowing rate of the lessee. The Company determines the incremental borrowing rate of the lessee on a lease-by-lease basis by developing an estimated centralized U.S. dollar borrowing rate for a fully collateralized obligation with a term similar to the lease term, and adjusts the rate to reflect the incremental risk associated with the currency in which the lease is denominated. Lease agreements of the Company may include options to extend or terminate the lease and the Company includes such options in the lease term when it is reasonably certain that the Company will exercise that option. RoU Assets are recognized based on the initial measurement of the lease liabilities plus initial direct costs less lease incentives and, according to the guidance for long-lived assets, RoU Assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Lease expense for operating leases is recognized on a straight-line basis over the lease term. The Company elected a practical expedient to account for lease and non-lease components together as a single lease component. The Company also elected the short-term lease recognition exemption for all classes of lease assets with an original term of twelve months or less. As part of the transition, the Company elected a package of practical expedients allowing it to carry forward historical accounting for any expired or existing contracts that are or contain lease contracts, including classification of such contracts and initial direct costs associated with them. The adoption of Topic 842 on January 1, 2019 resulted in the recognition of RoU Assets for operating leases of $177,597 and operating lease liabilities of $173,863 . The adoption of Topic 842 did not have a material impact on the condensed consolidated statement of income and comprehensive income, condensed consolidated statement of changes in stockholders’ equity or the condensed consolidated statement of cash flows. See Note 6 “Leases” in the condensed consolidated interim financial statements for additional information regarding leases. 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. Unless otherwise discussed below, 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. Measurement of Credit Losses on Financial Instruments — Effective January 1, 2020, the Company will be required to adopt the amended guidance of FASB ASC Topic 326, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , (with early adoption permitted effective January 1, 2019.) The amendments in this update change how companies measure and recognize credit impairment for many financial assets. The new expected credit loss model will require 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. Entities are required to adopt the standard using a modified-retrospective approach through a cumulative effect adjustment to retained earnings as of the beginning of the period of adoption. The Company has not yet completed its assessment of the impact of the new guidance on its consolidated financial statements and will adopt the standard on January 1, 2020.

FAIR VALUE MEASUREMENTS FAIR VA

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Policies)	9 Months Ended
	Sep. 30, 2019
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 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 business 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 agreement and adjusted those estimates to reflect the probability of their achievement. Those estimated future payments were then discounted to present value using a rate based on the weighted-average cost of capital of guideline companies. 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 consolidated statement of income and comprehensive income.

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Policies)	9 Months Ended
	Sep. 30, 2019
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 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.

REVENUES (Policies)

REVENUES (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Unbilled Revenues	Contract assets included in Unbilled revenues are recorded when services have been provided but the Company does not have an unconditional right to receive consideration.
Impairment Loss	The Company recognizes an impairment loss when the contract carrying amount is greater than the remaining consideration expected less the remaining costs of providing services.
Deferred Revenues	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.

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Fair Values of Net 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 and updated for any changes as of September 30, 2019 for each respective acquisition: Continuum Think test IO Cash and cash equivalents $ 2,251 $ 2,344 $ 668 Accounts receivable 6,676 2,259 727 Unbilled revenues 2,463 284 — Prepaid expenses and other current assets 936 609 96 Goodwill 26,617 22,211 12,084 Intangible assets 14,450 6,882 6,219 Property and equipment and other noncurrent assets 8,902 642 154 Total assets acquired $ 62,295 $ 35,231 $ 19,948 Accounts payable, accrued expenses and other current liabilities $ 2,745 $ 2,205 $ 877 Due to employees 1,001 13 42 Long-term debt 3,220 — — Other noncurrent liabilities 490 1,040 1,706 Total liabilities assumed $ 7,456 $ 3,258 $ 2,625 Net assets acquired $ 54,839 $ 31,973 $ 17,323
Fair Values and Useful Lives of Intangible Assets Acquired	The following table presents the estimated fair values and useful lives of intangible assets acquired from Continuum, Think, and test IO as of the date of acquisition and updated for any changes as of September 30, 2019 for each respective acquisition: Continuum Think test IO Weighted Average Useful Life (in years) Amount Weighted Average Useful Life (in years) Amount Weighted Average Useful Life (in years) Amount Customer relationships 6.5 $ 5,800 7 $ 6,117 7 $ 2,456 Favorable lease 11.2 5,500 — — — — Software — — — — 6 3,461 Contract royalties 8 1,900 — — — — Trade names 5 1,250 5 765 4 302 Total $ 14,450 $ 6,882 $ 6,219

GOODWILL (Tables)

GOODWILL (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 $ 103,542 $ 63,290 $ — $ 166,832 test IO acquisition 3,310 8,775 — 12,085 Other 2019 acquisitions 6,710 2,028 767 9,505 Think purchase accounting adjustments — (258 ) — (258 ) Effect of net foreign currency exchange rate changes (145 ) (1,714 ) (6 ) (1,865 ) Balance as of September 30, 2019 $ 113,417 $ 72,121 $ 761 $ 186,299

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018: As of September 30, 2019 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 1,189 $ — $ 1,189 $ — Total assets measured at fair value on a recurring basis $ 1,189 $ — $ 1,189 $ — Foreign exchange derivative liabilities $ 1,291 $ — $ 1,291 $ — Contingent consideration 9,572 — — 9,572 Total liabilities measured at fair value on a recurring basis $ 10,863 $ — $ 1,291 $ 9,572 As of December 31, 2018 Balance Level 1 Level 2 Level 3 Foreign exchange derivative assets $ 181 $ — $ 181 $ — Total assets measured at fair value on a recurring basis $ 181 $ — $ 181 $ — Foreign exchange derivative liabilities $ 3,475 $ — $ 3,475 $ — Contingent consideration 7,468 — — 7,468 Total liabilities measured at fair value on a recurring basis $ 10,943 $ — $ 3,475 $ 7,468
Acquisition-Related Contractual Contingent Liabilities Roll Forward	A reconciliation of the beginning and ending balances of Level 3 acquisition-related contractual contingent liabilities using significant unobservable inputs for the nine months ended September 30, 2019 is as follows: Amount Contingent consideration liabilities as of January 1, 2019 $ 7,468 Payment of contingent consideration (1,104 ) Acquisition date fair value of contractual contingent liabilities — Other 2019 Acquisitions (Note 2) 2,100 Changes in fair value of contingent consideration included in Interest and other income, net 1,356 Effect of net foreign currency exchange rate changes (248 ) Contingent consideration liabilities as of September 30, 2019 $ 9,572
Reported Amounts and Estimated Fair Values of the Financial Assets and Liabilities	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, 2019 Financial Assets: Cash and cash equivalents $ 853,241 $ 853,241 $ 853,241 $ — $ — Restricted cash $ 1,148 $ 1,148 $ 1,148 $ — $ — Employee loans $ 2,608 $ 2,608 $ — $ — $ 2,608 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,017 $ 25,017 $ — $ 25,017 $ — Fair Value Hierarchy Balance Estimated Fair Value Level 1 Level 2 Level 3 December 31, 2018 Financial Assets: Cash and cash equivalents $ 770,560 $ 770,560 $ 770,560 $ — $ — Restricted cash $ 1,151 $ 1,151 $ 1,151 $ — $ — Employee loans $ 3,525 $ 3,525 $ — $ — $ 3,525 Financial Liabilities: Borrowings under the 2017 Credit Facility $ 25,020 $ 25,020 $ — $ 25,020 $ —

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 and December 31, 2018 were as follows: As of September 30, 2019 As of December 31, 2018 Balance Sheet Classification Asset Derivatives Liability Derivatives Asset Derivatives Liability Derivatives Foreign exchange forward contracts - Designated as hedging instruments Prepaid expenses and other current assets $ 1,189 $ 181 Accrued expenses and other current liabilities $ 1,291 $ 3,475
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, 2019 and 2018 were as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 Foreign exchange forward contracts - Designated as hedging instruments: Change in fair value recognized in accumulated other comprehensive loss $ (2,791 ) $ (86 ) $ 3,192 $ (2,692 ) Net gain/(loss) reclassified from accumulated other comprehensive loss into cost of revenues (exclusive of depreciation and amortization) $ 848 $ (1,604 ) $ 738 $ (2,541 ) Foreign exchange forward contracts - Not designated as hedging instruments: Net gain recognized in foreign exchange (loss)/gain $ — $ — $ — $ 44

LEASES (Tables)

LEASES (Tables)	9 Months Ended
	Sep. 30, 2019
Leases [Abstract]
Components of Lease Expenses	During the three and nine months ended September 30, 2019 , the components of lease expense were as follows: Income Statement Classification Three Months Ended Nine Months Ended Operating lease cost Selling, general and administrative expenses $ 16,210 $ 45,125 Variable lease cost Selling, general and administrative expenses 2,439 6,535 Short-term lease cost Selling, general and administrative expenses 1,085 2,989 Sublease income Interest and other income, net (664 ) (1,596 ) Total lease cost $ 19,070 $ 53,053
Supplemental Cash Flow Information	Supplemental cash flow information related to leases was as follows: Three Months Ended Nine Months Ended Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows used for operating leases $ 14,709 $ 43,510 Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 14,251 $ 67,798 Non-cash net increase due to lease modifications: Operating lease right-of-use assets $ 3,233 $ 6,383 Operating lease liabilities $ 3,199 $ 6,451
Weighted Average Lease Terms and Discount Rates	Weighted average remaining lease term and discount rate as of September 30, 2019 were as follows: As of September 30, 2019 Weighted average remaining lease term, in years: Operating leases 5.9 Weighted average discount rate: Operating leases 3.8 %
Maturity of Operating Lease Liabilities	As of September 30, 2019 , operating lease liabilities will mature as follows: Year ending December 31, Lease Payments 2019 (excluding nine months ended September 30, 2019) $ 15,442 2020 55,258 2021 44,896 2022 28,396 2023 20,915 Thereafter 63,793 Total lease payments 228,700 Less: imputed interest (23,295 ) Total $ 205,405

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	9 Months Ended
	Sep. 30, 2019
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 3.1 % 3.5 % Irrevocable standby letters of credit $ 295 $ 382 Available borrowing capacity $ 274,705 $ 274,618 Current maximum borrowing capacity $ 300,000 $ 300,000

REVENUES (Tables)

REVENUES (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 349,875 $ 8,484 $ 42 $ 358,401 $ — $ 358,401 Europe 6,756 182,621 23 189,400 (88 ) 189,312 CIS 2,349 53 24,099 26,501 — 26,501 APAC 7 13,965 — 13,972 (83 ) 13,889 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 976,841 $ 32,928 $ 74 $ 1,009,843 $ (2 ) $ 1,009,841 Europe 16,736 523,487 263 540,486 (321 ) 540,165 CIS 6,093 66 63,608 69,767 (1 ) 69,766 APAC 1,045 40,317 — 41,362 (111 ) 41,251 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 271,551 $ 12,536 $ 17 $ 284,104 $ (27 ) $ 284,077 Europe 5,408 146,990 3 152,401 (166 ) 152,235 CIS 2,208 142 16,184 18,534 — 18,534 APAC 1,671 11,814 4 13,489 (149 ) 13,340 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Customer Locations North America $ 747,894 $ 40,074 $ 46 $ 788,014 $ (40 ) $ 787,974 Europe 11,234 444,468 45 455,747 (623 ) 455,124 CIS 6,300 233 53,192 59,725 — 59,725 APAC 3,709 31,545 91 35,345 (187 ) 35,158 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 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, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 50,510 $ 61,189 $ 18,760 $ 130,459 $ (122 ) $ 130,337 Travel & Consumer 51,476 57,780 3,171 112,427 (45 ) 112,382 Software & Hi-Tech 90,880 16,952 552 108,384 — 108,384 Business Information & Media 65,153 40,624 22 105,799 — 105,799 Life Sciences & Healthcare 60,049 6,713 7 66,769 — 66,769 Emerging Verticals 40,919 21,865 1,652 64,436 (4 ) 64,432 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 132,435 $ 182,143 $ 49,801 $ 364,379 $ (376 ) $ 364,003 Travel & Consumer 146,654 169,157 8,056 323,867 (45 ) 323,822 Software & Hi-Tech 255,601 56,764 1,470 313,835 (2 ) 313,833 Business Information & Media 189,854 108,852 266 298,972 (6 ) 298,966 Life Sciences & Healthcare 164,492 16,176 73 180,741 — 180,741 Emerging Verticals 111,679 63,706 4,279 179,664 (6 ) 179,658 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 30,488 $ 61,713 $ 12,786 $ 104,987 $ (189 ) $ 104,798 Travel & Consumer 45,690 53,634 1,891 101,215 (122 ) 101,093 Software & Hi-Tech 68,572 19,035 569 88,176 — 88,176 Business Information & Media 64,152 17,650 — 81,802 — 81,802 Life Sciences & Healthcare 39,550 5,078 12 44,640 (31 ) 44,609 Emerging Verticals 32,386 14,372 950 47,708 — 47,708 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Industry Verticals Financial Services $ 79,176 $ 190,027 $ 43,102 $ 312,305 $ (697 ) $ 311,608 Travel & Consumer 133,481 155,208 5,356 294,045 (122 ) 293,923 Software & Hi-Tech 193,672 59,186 1,957 254,815 — 254,815 Business Information & Media 181,021 54,637 — 235,658 — 235,658 Life Sciences & Healthcare 99,893 15,550 12 115,455 (31 ) 115,424 Emerging Verticals 81,894 41,712 2,947 126,553 — 126,553 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 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, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 322,573 $ 171,261 $ 13,815 $ 507,649 $ — $ 507,649 Fixed-price 35,273 33,093 10,304 78,670 — 78,670 Licensing 883 149 9 1,041 — 1,041 Other revenues 258 620 36 914 (171 ) 743 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 907,624 $ 507,055 $ 37,134 $ 1,451,813 $ — $ 1,451,813 Fixed-price 89,694 87,543 26,534 203,771 — 203,771 Licensing 2,343 689 211 3,243 — 3,243 Other revenues 1,054 1,511 66 2,631 (435 ) 2,196 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 256,549 $ 155,797 $ 9,441 $ 421,787 $ — $ 421,787 Fixed-price 23,241 15,001 6,759 45,001 — 45,001 Licensing 798 173 1 972 — 972 Other revenues 250 511 7 768 (342 ) 426 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Contract Types Time-and-material $ 704,612 $ 471,900 $ 29,302 $ 1,205,814 $ — $ 1,205,814 Fixed-price 61,716 42,035 24,038 127,789 — 127,789 Licensing 2,098 1,119 12 3,229 — 3,229 Other revenues 711 1,266 22 1,999 (850 ) 1,149 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981 Timing of Revenue Recognition The following tables present the timing of revenue recognition for the periods indicated: Three Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 561 $ 290 $ 54 $ 905 $ (171 ) $ 734 Transferred over time 358,426 204,833 24,110 587,369 — 587,369 Revenues $ 358,987 $ 205,123 $ 24,164 $ 588,274 $ (171 ) $ 588,103 Nine Months Ended September 30, 2019 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 1,185 $ 692 $ 55 $ 1,932 $ (435 ) $ 1,497 Transferred over time 999,530 596,106 63,890 1,659,526 — 1,659,526 Revenues $ 1,000,715 $ 596,798 $ 63,945 $ 1,661,458 $ (435 ) $ 1,661,023 Three Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 194 $ 289 $ — $ 483 $ (342 ) $ 141 Transferred over time 280,644 171,193 16,208 468,045 — 468,045 Revenues $ 280,838 $ 171,482 $ 16,208 $ 468,528 $ (342 ) $ 468,186 Nine Months Ended September 30, 2018 Reportable Segments North America Europe Russia Total Segment Revenues Other Income Included in Segment Revenues Consolidated Revenues Timing of Revenue Recognition Transferred at a point of time $ 832 $ 1,351 $ 10 $ 2,193 $ (850 ) $ 1,343 Transferred over time 768,305 514,969 53,364 1,336,638 — 1,336,638 Revenues $ 769,137 $ 516,320 $ 53,374 $ 1,338,831 $ (850 ) $ 1,337,981
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, 2019 . 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 $ 12,226 $ 2,774 $ 140 $ — $ 15,140
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 Unbilled revenues $ 24,870 $ 13,522 Contract liabilities included in Accrued expenses and other current liabilities $ 4,954 $ 4,558 Contract liabilities included in Other noncurrent liabilities $ 1 $ 224

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2019
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 2019 2018 2019 2018 Cost of revenues (exclusive of depreciation and amortization) $ 7,580 $ 7,492 $ 27,841 $ 22,835 Selling, general and administrative expenses 7,891 7,838 25,183 23,901 Total $ 15,471 $ 15,330 $ 53,024 $ 46,736
Stock Options Activity	Stock option activity under the Company’s plans is set forth below: Number of Options Weighted Average Exercise Price Aggregate Intrinsic Value Weighted Average Remaining Contractual Term (in years) Options outstanding at January 1, 2019 4,082,944 $ 44.54 Options granted 131,849 $ 169.13 Options modified 17,871 $ 163.55 Options exercised (668,339 ) $ 43.09 Options forfeited/cancelled (10,701 ) $ 97.83 Options outstanding at September 30, 2019 3,553,624 $ 49.87 $ 470,672 4.9 Options vested and exercisable at September 30, 2019 3,129,141 $ 41.01 $ 442,179 4.5 Options expected to vest at September 30, 2019 397,070 $ 114.20 $ 27,050 8.3
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, 2019 : 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 Fair Value Per Share Number of Shares Weighted Average Grant Date Fair Value Per Share Number of Shares Weighted Average Grant Date Fair Value Per Share Unvested service-based awards outstanding at January 1, 2019 793 $ 63.10 797,903 $ 92.13 302,967 $ 83.99 Awards granted 9,394 $ 167.18 282,628 $ 170.25 55,912 $ 170.12 Awards modified — $ — 6,897 $ 170.74 668 $ 168.36 Awards vested (396 ) $ 63.10 (273,119 ) $ 86.38 (110,012 ) $ 80.34 Awards forfeited/cancelled — $ — (35,004 ) $ 111.93 (4,856 ) $ 94.73 Unvested service-based awards outstanding at September 30, 2019 9,791 $ 162.96 779,305 $ 122.28 244,679 $ 105.33
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, 2019 : Equity-Classified Equity-Settled Restricted Stock Units Equity-Classified Number of Shares Weighted Average Grant Date Fair Value Per Share Number of Weighted Average Grant Date Unvested performance-based awards outstanding at January 1, 2019 29,592 $ 121.75 — $ — Awards granted — $ — 9,393 $ 165.87 Awards modified (29,592 ) $ 121.75 — $ — Unvested performance-based awards outstanding at September 30, 2019 — $ — 9,393 $ 165.87

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2019
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 2019 2018 2019 2018 Numerator for basic and diluted earnings per share: Net income $ 67,002 $ 65,618 $ 186,533 $ 180,291 Numerator for basic and diluted earnings per share $ 67,002 $ 65,618 $ 186,533 $ 180,291 Denominator: Weighted average common shares for basic earnings per share 54,877,666 53,851,865 54,603,903 53,485,339 Net effect of dilutive stock options, restricted stock units and restricted stock awards 2,966,689 3,111,002 2,963,436 3,114,299 Weighted average common shares for diluted earnings per share 57,844,355 56,962,867 57,567,339 56,599,638 Net income per share: Basic $ 1.22 $ 1.22 $ 3.42 $ 3.37 Diluted $ 1.16 $ 1.15 $ 3.24 $ 3.19

SEGMENTS INFORMATION (Tables)

SEGMENTS INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Revenues from External Customers and Operating Profit, Before Unallocated Expenses	Revenues from external customers and operating profit, before unallocated expenses, by reportable segments for the three and nine months ended September 30, 2019 and 2018 , were as follows: Three Months Ended Nine Months Ended 2019 2018 2019 2018 Segment revenues: North America $ 358,987 $ 280,838 $ 1,000,715 $ 769,137 Europe 205,123 171,482 596,798 516,320 Russia 24,164 16,208 63,945 53,374 Total segment revenues $ 588,274 $ 468,528 $ 1,661,458 $ 1,338,831 Segment operating profit: North America $ 79,310 $ 60,763 $ 213,114 $ 155,944 Europe 27,550 28,871 87,014 84,329 Russia 5,524 543 11,765 8,211 Total segment operating profit $ 112,384 $ 90,177 $ 311,893 $ 248,484
Reconciliation of Segment Revenues to Consolidated Revenues and Segment Operating Profit to Consolidated Income Before Provision for/(Benefit from) Income Taxes	Reconciliation of segment revenues to consolidated revenues and segment operating profit to consolidated income before provision for/(benefit from) income taxes is presented below: Three Months Ended Nine Months Ended 2019 2018 2019 2018 Total segment revenues $ 588,274 $ 468,528 $ 1,661,458 $ 1,338,831 Other income included in segment revenues (171 ) (342 ) (435 ) (850 ) Revenues $ 588,103 $ 468,186 $ 1,661,023 $ 1,337,981 Total segment operating profit: $ 112,384 $ 90,177 $ 311,893 $ 248,484 Unallocated amounts: Other income included in segment revenues (171 ) (342 ) (435 ) (850 ) Stock-based compensation expense (15,471 ) (15,330 ) (53,024 ) (46,736 ) Non-corporate taxes (3,960 ) (2,063 ) (8,126 ) (7,041 ) Professional fees (1,502 ) (1,420 ) (3,826 ) (4,736 ) Depreciation and amortization expense (2,585 ) (2,011 ) (7,328 ) (5,754 ) Bank charges (645 ) (782 ) (1,937 ) (1,950 ) One-time charges and other acquisition-related expenses (1,142 ) (155 ) (2,503 ) (2,016 ) Other operating expenses (6,343 ) (3,514 ) (16,609 ) (11,907 ) Income from operations 80,565 64,560 218,105 167,494 Interest and other income, net 2,509 1,941 6,775 2,442 Foreign exchange (loss)/gain (3,105 ) (514 ) (10,151 ) 1,069 Income before provision for/(benefit from) income taxes $ 79,969 $ 65,987 $ 214,729 $ 171,005
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 $ 48,521 $ 50,085 Ukraine 16,077 8,433 United States 13,934 13,101 Russia 12,514 9,902 India 6,742 7,019 Hungary 3,329 3,168 China 3,132 2,651 Poland 2,900 2,637 Other 8,172 5,650 Total $ 115,321 $ 102,646
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, 2019 and 2018 : Three Months Ended Nine Months Ended 2019 2018 2019 2018 United States $ 340,803 $ 266,065 $ 959,471 $ 736,579 United Kingdom 74,992 50,482 209,773 152,315 Switzerland 38,781 35,524 110,378 105,396 Russia 23,668 15,609 62,020 51,930 Netherlands 22,161 17,031 63,816 51,934 Germany 20,940 20,732 59,716 60,331 Canada 17,582 18,008 50,339 51,391 Other 49,176 44,735 145,510 128,105 Total $ 588,103 $ 468,186 $ 1,661,023 $ 1,337,981

BUSINESS AND SUMMARY OF SIGNI_3

BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Leases) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
RoU Asset for operating leases	$ 207,145		$ 0
Operating lease liabilities	$ 205,405
Topic 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
RoU Asset for operating leases		$ 177,597
Operating lease liabilities		$ 173,863

ACQUISITIONS (Narrative) (Detai

ACQUISITIONS (Narrative) (Details) $ in Thousands	Apr. 30, 2019USD ($)	Nov. 01, 2018USD ($)	Mar. 15, 2018USD ($)	Sep. 30, 2019USD ($)
Continuum
Business Acquisition [Line Items]
Acquisition date			Mar. 15, 2018
Cash consideration			$ 52,515
Estimated future operating results, period			12 months
Maximum amount of earnout payable			$ 3,135
Continuum | Design Consultants
Business Acquisition [Line Items]
Numbers of employees acquired			125
Think
Business Acquisition [Line Items]
Acquisition date		Nov. 1, 2018
Cash consideration		$ 26,254
Estimated future operating results, period		12 months
Maximum amount of earnout payable		$ 8,156
True-up payment				$ (271)
test IO
Business Acquisition [Line Items]
Acquisition date	Apr. 30, 2019
Cash consideration	$ 17,323
Equity interest acquired	100.00%
Other 2019 Acquisitions
Business Acquisition [Line Items]
Cash consideration				14,080
Maximum amount of earnout payable				$ 3,000
Other 2019 Acquisitions | Minimum
Business Acquisition [Line Items]
Estimated future operating results, period				12 months
Other 2019 Acquisitions | Maximum
Business Acquisition [Line Items]
Estimated future operating results, period				24 months

ACQUISITIONS (Fair Values of Ne

ACQUISITIONS (Fair Values of Net Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Apr. 30, 2019	Nov. 01, 2018	Mar. 15, 2018
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Unbilled revenues	$ 142,949	$ 104,652
Goodwill	186,299	166,832
Continuum
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents					$ 2,251
Accounts receivable					6,676
Unbilled revenues					2,463
Prepaid and other current assets					936
Goodwill					26,617
Intangible assets					14,450
Property and equipment and other noncurrent assets					8,902
Total assets acquired					62,295
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Accounts payable, accrued expenses and other current liabilities					2,745
Due to employees					1,001
Long-term debt					3,220
Other noncurrent liabilities					490
Total liabilities assumed					7,456
Net assets acquired					$ 54,839
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Adjustments recorded to the estimated fair values of the assets acquired and liabilities assumed at the acquisition date		$ 76
Think
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents				$ 2,344
Accounts receivable				2,259
Unbilled revenues				284
Prepaid and other current assets				609
Goodwill				22,211
Intangible assets				6,882
Property and equipment and other noncurrent assets				642
Total assets acquired				35,231
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Accounts payable, accrued expenses and other current liabilities				2,205
Due to employees				13
Long-term debt				0
Other noncurrent liabilities				1,040
Total liabilities assumed				3,258
Net assets acquired				$ 31,973
test IO
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract]
Cash and cash equivalents			$ 668
Accounts receivable			727
Unbilled revenues			0
Prepaid and other current assets			96
Goodwill			12,084
Intangible assets			6,219
Property and equipment and other noncurrent assets			154
Total assets acquired			19,948
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract]
Accounts payable, accrued expenses and other current liabilities			877
Due to employees			42
Long-term debt			0
Other noncurrent liabilities			1,706
Total liabilities assumed			2,625
Net assets acquired			$ 17,323
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Adjustments recorded to the estimated fair values of the assets acquired and liabilities assumed at the acquisition date	119
Adjustment recorded to intangible assets and goodwill	$ (145)

ACQUISITIONS (Fair Values and U

ACQUISITIONS (Fair Values and Useful Lives of Intangible Assets Acquired) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Continuum
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 14,450
Continuum | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	6 years 6 months
Estimated fair value of intangible assets acquired	$ 5,800
Continuum | Favorable lease
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	11 years 2 months 12 days
Estimated fair value of intangible assets acquired	$ 5,500
Continuum | Software
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 0
Continuum | Contract royalties
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	8 years
Estimated fair value of intangible assets acquired	$ 1,900
Continuum | Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	5 years
Estimated fair value of intangible assets acquired	$ 1,250
Think
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 6,882
Think | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	7 years
Estimated fair value of intangible assets acquired	$ 6,117
Think | Favorable lease
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	0
Think | Software
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	0
Think | Contract royalties
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 0
Think | Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	5 years
Estimated fair value of intangible assets acquired	$ 765
test IO
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 6,219
test IO | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	7 years
Estimated fair value of intangible assets acquired	$ 2,456
test IO | Favorable lease
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 0
test IO | Software
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	6 years
Estimated fair value of intangible assets acquired	$ 3,461
test IO | Contract royalties
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated fair value of intangible assets acquired	$ 0
test IO | Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted average useful life	4 years
Estimated fair value of intangible assets acquired	$ 302

ACQUISITIONS (Income Statement

ACQUISITIONS (Income Statement Effect) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition [Line Items]
Revenues	$ 588,103	$ 468,186	$ 1,661,023	$ 1,337,981
test IO
Business Acquisition [Line Items]
Revenues	1,692		2,606
Other 2019 Acquisitions
Business Acquisition [Line Items]
Revenues	$ 3,009		$ 3,009

GOODWILL (Goodwill Roll Forward

GOODWILL (Goodwill Roll Forward) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Goodwill [Roll Forward]
Balance as of January 1, 2019	$ 166,832
Effect of net foreign currency exchange rate changes	(1,865)
Balance as of September 30, 2019	186,299
test IO
Goodwill [Roll Forward]
Acquisition	12,085
Other 2019 Acquisitions
Goodwill [Roll Forward]
Acquisition	9,505
Think
Goodwill [Roll Forward]
Purchase accounting adjustments	(258)
North America
Goodwill [Roll Forward]
Balance as of January 1, 2019	103,542
Effect of net foreign currency exchange rate changes	(145)
Balance as of September 30, 2019	113,417
North America | test IO
Goodwill [Roll Forward]
Acquisition	3,310
North America | Other 2019 Acquisitions
Goodwill [Roll Forward]
Acquisition	6,710
North America | Think
Goodwill [Roll Forward]
Purchase accounting adjustments	0
Europe
Goodwill [Roll Forward]
Balance as of January 1, 2019	63,290
Effect of net foreign currency exchange rate changes	(1,714)
Balance as of September 30, 2019	72,121
Europe | test IO
Goodwill [Roll Forward]
Acquisition	8,775
Europe | Other 2019 Acquisitions
Goodwill [Roll Forward]
Acquisition	2,028
Europe | Think
Goodwill [Roll Forward]
Purchase accounting adjustments	(258)
Russia
Goodwill [Roll Forward]
Balance as of January 1, 2019	0
Effect of net foreign currency exchange rate changes	(6)
Balance as of September 30, 2019	761
Russia | test IO
Goodwill [Roll Forward]
Acquisition	0
Russia | Other 2019 Acquisitions
Goodwill [Roll Forward]
Acquisition	767
Russia | Think
Goodwill [Roll Forward]
Purchase accounting adjustments	$ 0

GOODWILL (Goodwill Accumulated

GOODWILL (Goodwill Accumulated Impaitment Losses) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
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, 2019	Dec. 31, 2018
Financial Assets:
Total assets measured at fair value on a recurring basis	$ 1,189	$ 181
Financial Liabilities:
Contingent consideration	9,572	7,468
Total liabilities measured at fair value on a recurring basis	10,863	10,943
Foreign exchange contracts
Financial Assets:
Derivative assets	1,189	181
Financial Liabilities:
Derivative liabilities	1,291	3,475
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	1,189	181
Financial Liabilities:
Contingent consideration	0	0
Total liabilities measured at fair value on a recurring basis	1,291	3,475
Level 2 | Foreign exchange contracts
Financial Assets:
Derivative assets	1,189	181
Financial Liabilities:
Derivative liabilities	1,291	3,475
Level 3
Financial Assets:
Total assets measured at fair value on a recurring basis	0	0
Financial Liabilities:
Contingent consideration	9,572	7,468
Total liabilities measured at fair value on a recurring basis	9,572	7,468
Level 3 | Foreign exchange contracts
Financial Assets:
Derivative assets	0	0
Financial Liabilities:
Derivative liabilities	$ 0	$ 0

FAIR VALUE MEASUREMENTS (Narrat

FAIR VALUE MEASUREMENTS (Narrative) (Details) - USD ($) $ in Thousands	Nov. 01, 2018	Mar. 15, 2018	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Acquisition, Contingent Consideration [Line Items]
Cash payment to extinguish the earnout obligation						$ (1,104)	$ 0
Continuum
Business Acquisition, Contingent Consideration [Line Items]
Estimated future operating results, period		12 months
Contingent consideration liability		$ 2,400
Contingent consideration liability adjustment				$ (396)	$ (900)
Cash payment to extinguish the earnout obligation				(1,104)
Think
Business Acquisition, Contingent Consideration [Line Items]
Estimated future operating results, period	12 months
Contingent consideration liability	$ 5,990
Contingent consideration liability adjustment				$ 1,752
Minimum | Other 2019 Acquisitions
Business Acquisition, Contingent Consideration [Line Items]
Estimated future operating results, period			12 months
Maximum | Other 2019 Acquisitions
Business Acquisition, Contingent Consideration [Line Items]
Estimated future operating results, period			24 months

FAIR VALUE MEASUREMENTS (Acquis

FAIR VALUE MEASUREMENTS (Acquisition-Related Contractual Contingent Liabilities Roll Forward) (Details) - Level 3 $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent consideration liabilities as of January 1, 2019	$ 7,468
Payment of contingent consideration	(1,104)
Effect of net foreign currency exchange rate changes	(248)
Contingent consideration liabilities as of September 30, 2019	9,572
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	1,356
Other 2019 Acquisitions
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Acquisition date fair value of contractual contingent liabilities	$ 2,100

FAIR VALUE MEASUREMENTS (Report

FAIR VALUE MEASUREMENTS (Reported Amounts and Estimated Fair Values of the Financial Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Balance
Financial Assets:
Cash and cash equivalents	$ 853,241	$ 770,560
Restricted cash	1,148	1,151
Employee loans	2,608	3,525
Balance | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	25,017	25,020
Estimated Fair Value
Financial Assets:
Cash and cash equivalents	853,241	770,560
Restricted cash	1,148	1,151
Employee loans	2,608	3,525
Estimated Fair Value | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	25,017	25,020
Estimated Fair Value | Level 1
Financial Assets:
Cash and cash equivalents	853,241	770,560
Restricted cash	1,148	1,151
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 and cash equivalents	0	0
Restricted cash	0	0
Employee loans	0	0
Estimated Fair Value | Level 2 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	25,017	25,020
Estimated Fair Value | Level 3
Financial Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Employee loans	2,608	3,525
Estimated Fair Value | Level 3 | Revolving credit facility | Credit Facility 2017
Financial Liabilities:
Borrowings	$ 0	$ 0

DERIVATIVE FINANCIAL INSTRUME_4

DERIVATIVE FINANCIAL INSTRUMENTS (Fair Value of Derivative Instruments) (Details) - Foreign exchange contracts - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
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	1,189	$ 181
Designated as hedging instruments | Cash Flow Hedging | Accrued expenses and other current liabilities
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 1,291	$ 3,475

DERIVATIVE FINANCIAL INSTRUME_5

DERIVATIVE FINANCIAL INSTRUMENTS (Changes in the Fair Value of Derivative Instruments) (Details) - Foreign exchange contracts - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Designated as hedging instruments | Cash Flow Hedging | Cost of revenues (exclusive of depreciation and amortization)
Derivative Instruments, Gain (Loss) [Line Items]
Net gain/(loss) reclassified	$ 848	$ (1,604)	$ 738	$ (2,541)
Designated as hedging instruments | Cash Flow Hedging | Accumulated other comprehensive loss
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value	(2,791)	(86)	3,192	(2,692)
Not designated as hedging instruments | Foreign exchange loss
Derivative Instruments, Gain (Loss) [Line Items]
Net gain recognized	$ 0	$ 0	$ 0	$ 44

LEASES (Narrative) (Details)

LEASES (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Existence of material residual value guarantees	false
Existence of material restrictive covenants	There were no lease agreements that contained material restrictive covenants
Existance of lease agreements signed with related parties	There were no lease agreements signed with related parties
Commitments related to operating lease agreements that have not yet commenced	$ 69,683
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 2 months 12 days
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	11 years 7 months 6 days
Lease term of lease agreements that have not yet commenced	11 years 7 months 6 days

LEASES (Components of Lease Exp

LEASES (Components of Lease Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lease, Cost [Line Items]
Total lease cost	$ 19,070	$ 53,053
Selling, general and administrative expenses
Lease, Cost [Line Items]
Operating lease cost	16,210	45,125
Variable lease cost	2,439	6,535
Short-term lease cost	1,085	2,989
Interest and other income, net
Lease, Cost [Line Items]
Sublease income	$ (664)	$ (1,596)

LEASES (Supplemental Cash Flow

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

LEASES (Weighted Average Lease

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

LEASES (Maturity of Operating L

LEASES (Maturity of Operating Lease Liabilities) (Details) $ in Thousands	Sep. 30, 2019USD ($)
Leases [Abstract]
2019 (excluding nine months ended September 30, 2019)	$ 15,442
2020	55,258
2021	44,896
2022	28,396
2023	20,915
Thereafter	63,793
Total lease payments	228,700
Less: imputed interest	(23,295)
Total	$ 205,405

LONG-TERM DEBT (Details)

LONG-TERM DEBT (Details) - Credit Facility 2017 - USD ($) $ in Thousands	May 24, 2017	Sep. 30, 2019	Dec. 31, 2018
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		3.10%	3.50%
Available borrowing capacity		$ 274,705	$ 274,618
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		$ 295	$ 382

REVENUES (Disaggregation of Rev

REVENUES (Disaggregation of Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues	$ 588,103	$ 468,186	$ 1,661,023	$ 1,337,981
Transferred at a point of time
Disaggregation of Revenue [Line Items]
Revenues	734	141	1,497	1,343
Transferred over time
Disaggregation of Revenue [Line Items]
Revenues	587,369	468,045	1,659,526	1,336,638
Time-and-material
Disaggregation of Revenue [Line Items]
Revenues	507,649	421,787	1,451,813	1,205,814
Fixed-price
Disaggregation of Revenue [Line Items]
Revenues	78,670	45,001	203,771	127,789
Licensing
Disaggregation of Revenue [Line Items]
Revenues	1,041	972	3,243	3,229
Other revenues
Disaggregation of Revenue [Line Items]
Revenues	743	426	2,196	1,149
Financial Services
Disaggregation of Revenue [Line Items]
Revenues	130,337	104,798	364,003	311,608
Travel & Consumer
Disaggregation of Revenue [Line Items]
Revenues	112,382	101,093	323,822	293,923
Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Revenues	108,384	88,176	313,833	254,815
Business Information & Media
Disaggregation of Revenue [Line Items]
Revenues	105,799	81,802	298,966	235,658
Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Revenues	66,769	44,609	180,741	115,424
Emerging Verticals
Disaggregation of Revenue [Line Items]
Revenues	64,432	47,708	179,658	126,553
North America
Disaggregation of Revenue [Line Items]
Revenues	358,401	284,077	1,009,841	787,974
Europe
Disaggregation of Revenue [Line Items]
Revenues	189,312	152,235	540,165	455,124
CIS
Disaggregation of Revenue [Line Items]
Revenues	26,501	18,534	69,766	59,725
APAC
Disaggregation of Revenue [Line Items]
Revenues	13,889	13,340	41,251	35,158
North America
Disaggregation of Revenue [Line Items]
Segment revenues	358,987	280,838	1,000,715	769,137
North America | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Segment revenues	561	194	1,185	832
North America | Transferred over time
Disaggregation of Revenue [Line Items]
Segment revenues	358,426	280,644	999,530	768,305
North America | Time-and-material
Disaggregation of Revenue [Line Items]
Segment revenues	322,573	256,549	907,624	704,612
North America | Fixed-price
Disaggregation of Revenue [Line Items]
Segment revenues	35,273	23,241	89,694	61,716
North America | Licensing
Disaggregation of Revenue [Line Items]
Segment revenues	883	798	2,343	2,098
North America | Other revenues
Disaggregation of Revenue [Line Items]
Segment revenues	258	250	1,054	711
North America | Financial Services
Disaggregation of Revenue [Line Items]
Segment revenues	50,510	30,488	132,435	79,176
North America | Travel & Consumer
Disaggregation of Revenue [Line Items]
Segment revenues	51,476	45,690	146,654	133,481
North America | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Segment revenues	90,880	68,572	255,601	193,672
North America | Business Information & Media
Disaggregation of Revenue [Line Items]
Segment revenues	65,153	64,152	189,854	181,021
North America | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Segment revenues	60,049	39,550	164,492	99,893
North America | Emerging Verticals
Disaggregation of Revenue [Line Items]
Segment revenues	40,919	32,386	111,679	81,894
North America | North America
Disaggregation of Revenue [Line Items]
Segment revenues	349,875	271,551	976,841	747,894
North America | Europe
Disaggregation of Revenue [Line Items]
Segment revenues	6,756	5,408	16,736	11,234
North America | CIS
Disaggregation of Revenue [Line Items]
Segment revenues	2,349	2,208	6,093	6,300
North America | APAC
Disaggregation of Revenue [Line Items]
Segment revenues	7	1,671	1,045	3,709
Europe
Disaggregation of Revenue [Line Items]
Segment revenues	205,123	171,482	596,798	516,320
Europe | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Segment revenues	290	289	692	1,351
Europe | Transferred over time
Disaggregation of Revenue [Line Items]
Segment revenues	204,833	171,193	596,106	514,969
Europe | Time-and-material
Disaggregation of Revenue [Line Items]
Segment revenues	171,261	155,797	507,055	471,900
Europe | Fixed-price
Disaggregation of Revenue [Line Items]
Segment revenues	33,093	15,001	87,543	42,035
Europe | Licensing
Disaggregation of Revenue [Line Items]
Segment revenues	149	173	689	1,119
Europe | Other revenues
Disaggregation of Revenue [Line Items]
Segment revenues	620	511	1,511	1,266
Europe | Financial Services
Disaggregation of Revenue [Line Items]
Segment revenues	61,189	61,713	182,143	190,027
Europe | Travel & Consumer
Disaggregation of Revenue [Line Items]
Segment revenues	57,780	53,634	169,157	155,208
Europe | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Segment revenues	16,952	19,035	56,764	59,186
Europe | Business Information & Media
Disaggregation of Revenue [Line Items]
Segment revenues	40,624	17,650	108,852	54,637
Europe | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Segment revenues	6,713	5,078	16,176	15,550
Europe | Emerging Verticals
Disaggregation of Revenue [Line Items]
Segment revenues	21,865	14,372	63,706	41,712
Europe | North America
Disaggregation of Revenue [Line Items]
Segment revenues	8,484	12,536	32,928	40,074
Europe | Europe
Disaggregation of Revenue [Line Items]
Segment revenues	182,621	146,990	523,487	444,468
Europe | CIS
Disaggregation of Revenue [Line Items]
Segment revenues	53	142	66	233
Europe | APAC
Disaggregation of Revenue [Line Items]
Segment revenues	13,965	11,814	40,317	31,545
Russia
Disaggregation of Revenue [Line Items]
Segment revenues	24,164	16,208	63,945	53,374
Russia | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Segment revenues	54	0	55	10
Russia | Transferred over time
Disaggregation of Revenue [Line Items]
Segment revenues	24,110	16,208	63,890	53,364
Russia | Time-and-material
Disaggregation of Revenue [Line Items]
Segment revenues	13,815	9,441	37,134	29,302
Russia | Fixed-price
Disaggregation of Revenue [Line Items]
Segment revenues	10,304	6,759	26,534	24,038
Russia | Licensing
Disaggregation of Revenue [Line Items]
Segment revenues	9	1	211	12
Russia | Other revenues
Disaggregation of Revenue [Line Items]
Segment revenues	36	7	66	22
Russia | Financial Services
Disaggregation of Revenue [Line Items]
Segment revenues	18,760	12,786	49,801	43,102
Russia | Travel & Consumer
Disaggregation of Revenue [Line Items]
Segment revenues	3,171	1,891	8,056	5,356
Russia | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Segment revenues	552	569	1,470	1,957
Russia | Business Information & Media
Disaggregation of Revenue [Line Items]
Segment revenues	22	0	266	0
Russia | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Segment revenues	7	12	73	12
Russia | Emerging Verticals
Disaggregation of Revenue [Line Items]
Segment revenues	1,652	950	4,279	2,947
Russia | North America
Disaggregation of Revenue [Line Items]
Segment revenues	42	17	74	46
Russia | Europe
Disaggregation of Revenue [Line Items]
Segment revenues	23	3	263	45
Russia | CIS
Disaggregation of Revenue [Line Items]
Segment revenues	24,099	16,184	63,608	53,192
Russia | APAC
Disaggregation of Revenue [Line Items]
Segment revenues	0	4	0	91
Total Segments
Disaggregation of Revenue [Line Items]
Segment revenues	588,274	468,528	1,661,458	1,338,831
Total Segments | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Segment revenues	905	483	1,932	2,193
Total Segments | Transferred over time
Disaggregation of Revenue [Line Items]
Segment revenues	587,369	468,045	1,659,526	1,336,638
Total Segments | Time-and-material
Disaggregation of Revenue [Line Items]
Segment revenues	507,649	421,787	1,451,813	1,205,814
Total Segments | Fixed-price
Disaggregation of Revenue [Line Items]
Segment revenues	78,670	45,001	203,771	127,789
Total Segments | Licensing
Disaggregation of Revenue [Line Items]
Segment revenues	1,041	972	3,243	3,229
Total Segments | Other revenues
Disaggregation of Revenue [Line Items]
Segment revenues	914	768	2,631	1,999
Total Segments | Financial Services
Disaggregation of Revenue [Line Items]
Segment revenues	130,459	104,987	364,379	312,305
Total Segments | Travel & Consumer
Disaggregation of Revenue [Line Items]
Segment revenues	112,427	101,215	323,867	294,045
Total Segments | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Segment revenues	108,384	88,176	313,835	254,815
Total Segments | Business Information & Media
Disaggregation of Revenue [Line Items]
Segment revenues	105,799	81,802	298,972	235,658
Total Segments | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Segment revenues	66,769	44,640	180,741	115,455
Total Segments | Emerging Verticals
Disaggregation of Revenue [Line Items]
Segment revenues	64,436	47,708	179,664	126,553
Total Segments | North America
Disaggregation of Revenue [Line Items]
Segment revenues	358,401	284,104	1,009,843	788,014
Total Segments | Europe
Disaggregation of Revenue [Line Items]
Segment revenues	189,400	152,401	540,486	455,747
Total Segments | CIS
Disaggregation of Revenue [Line Items]
Segment revenues	26,501	18,534	69,767	59,725
Total Segments | APAC
Disaggregation of Revenue [Line Items]
Segment revenues	13,972	13,489	41,362	35,345
Other Income Included in Segment Revenues
Disaggregation of Revenue [Line Items]
Segment revenues	(171)	(342)	(435)	(850)
Other income included in segment revenues	(171)	(342)	(435)	(850)
Other Income Included in Segment Revenues | Transferred at a point of time
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	(171)	(342)	(435)	(850)
Other Income Included in Segment Revenues | Transferred over time
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	0	0
Other Income Included in Segment Revenues | Time-and-material
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	0	0
Other Income Included in Segment Revenues | Fixed-price
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	0	0
Other Income Included in Segment Revenues | Licensing
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	0	0
Other Income Included in Segment Revenues | Other revenues
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	(171)	(342)	(435)	(850)
Other Income Included in Segment Revenues | Financial Services
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	(122)	(189)	(376)	(697)
Other Income Included in Segment Revenues | Travel & Consumer
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	(45)	(122)	(45)	(122)
Other Income Included in Segment Revenues | Software & Hi-Tech
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	(2)	0
Other Income Included in Segment Revenues | Business Information & Media
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	(6)	0
Other Income Included in Segment Revenues | Life Sciences & Healthcare
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	(31)	0	(31)
Other Income Included in Segment Revenues | Emerging Verticals
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	(4)	0	(6)	0
Other Income Included in Segment Revenues | North America
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	(27)	(2)	(40)
Other Income Included in Segment Revenues | Europe
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	(88)	(166)	(321)	(623)
Other Income Included in Segment Revenues | CIS
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	0	0	(1)	0
Other Income Included in Segment Revenues | APAC
Disaggregation of Revenue [Line Items]
Other income included in segment revenues	$ (83)	$ (149)	$ (111)	$ (187)

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, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue related to partially or fully unsatisfied performance obligations	$ 15,140
Less than 1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue related to partially or fully unsatisfied performance obligations	12,226
1 Year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue related to partially or fully unsatisfied performance obligations	2,774
2 Years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue related to partially or fully unsatisfied performance obligations	140
3 Years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue related to partially or fully unsatisfied performance obligations	$ 0

REVENUES (Contract Balances) (D

REVENUES (Contract Balances) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Change in Contract with Customer, Asset and Liability [Abstract]
Revenues from performance obligations satisfied in previous period	$ 4,915	$ 3,610	$ 7,039	$ 6,627
Change in Contract with Customer, Liability [Abstract]
Revenue recognized	140		3,801
Unbilled revenues	24,870		24,870		$ 13,522
Accrued expenses and other current liabilities
Change in Contract with Customer, Liability [Abstract]
Deferred revenues	4,954		4,954		4,558
Other noncurrent liabilities
Change in Contract with Customer, Liability [Abstract]
Deferred revenues	$ 1		$ 1		$ 224

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 15,471	$ 15,330	$ 53,024	$ 46,736
Cost of revenues (exclusive of depreciation and amortization)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	7,580	7,492	27,841	22,835
Selling, general and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,891	$ 7,838	$ 25,183	$ 23,901

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, 2019
Number of Options
Options outstanding at January 1, 2019	4,082,944
Options granted	131,849
Options modified	17,871
Options exercised	(668,339)
Options forfeited/cancelled	(10,701)
Options outstanding at September 30, 2019	3,553,624
Options vested and exercisable at September 30, 2019	3,129,141
Options expected to vest at September 30, 2019	397,070
Weighted Average Exercise Price
Options outstanding at January 1, 2019	$ 44.54
Options granted	169.13
Options modified	163.55
Options exercised	43.09
Options forfeited/cancelled	97.83
Options outstanding at September 30, 2019	49.87
Options vested and exercisable at September 30, 2019	41.01
Options expected to vest at September 30, 2019	$ 114.20
Aggregate Intrinsic Value
Options outstanding at September 30, 2019	$ 470,672
Options vested and exercisable at September 30, 2019	442,179
Options expected to vest at September 30, 2019	$ 27,050
Weighted Average Remaining Contractual Term (in years)
Options outstanding at September 30, 2019	4 years 10 months 24 days
Options vested and exercisable at September 30, 2019	4 years 6 months
Options expected to vest at September 30, 2019	8 years 3 months 18 days

STOCK-BASED COMPENSATION (Sto_2

STOCK-BASED COMPENSATION (Stock Option Additional Information) (Details) - Employee Stock Option $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	$ 13,619
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
	Sep. 30, 2019	Sep. 30, 2019
Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock Units
Number of Shares
Unvested awards outstanding at January 1, 2019		797,903
Awards granted		282,628
Awards modified		6,897
Awards vested		(273,119)
Awards forfeited/cancelled		(35,004)
Unvested awards outstanding at September 30, 2019	779,305	779,305
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2019		$ 92.13
Awards granted		170.25
Awards modified		170.74
Awards vested		86.38
Awards forfeited/cancelled		111.93
Unvested awards outstanding at September 30, 2019	$ 122.28	$ 122.28
Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock
Number of Shares
Unvested awards outstanding at January 1, 2019		793
Awards granted		9,394
Awards modified		0
Awards vested		(396)
Awards forfeited/cancelled		0
Unvested awards outstanding at September 30, 2019	9,791	9,791
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2019		$ 63.10
Awards granted		167.18
Awards modified		0
Awards vested		63.10
Awards forfeited/cancelled		0
Unvested awards outstanding at September 30, 2019	$ 162.96	$ 162.96
Service Period | Liability Classified Award | Cash-Settled Award | Restricted Stock Units
Number of Shares
Unvested awards outstanding at January 1, 2019		302,967
Awards granted		55,912
Awards modified		668
Awards vested		(110,012)
Awards forfeited/cancelled		(4,856)
Unvested awards outstanding at September 30, 2019	244,679	244,679
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2019		$ 83.99
Awards granted		170.12
Awards modified		168.36
Awards vested		80.34
Awards forfeited/cancelled		94.73
Unvested awards outstanding at September 30, 2019	$ 105.33	$ 105.33
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted Stock Units
Number of Shares
Unvested awards outstanding at January 1, 2019		29,592
Awards granted		0
Awards modified		(29,592)
Unvested awards outstanding at September 30, 2019	0	0
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2019		$ 121.75
Awards granted		0
Awards modified		121.75
Unvested awards outstanding at September 30, 2019	$ 0	$ 0
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted Stock
Number of Shares
Unvested awards outstanding at January 1, 2019		0
Awards granted		9,393
Awards modified		0
Unvested awards outstanding at September 30, 2019	9,393	9,393
Weighted Average Grant Date Fair Value Per Share
Unvested awards outstanding at January 1, 2019		$ 0
Awards granted		165.87
Awards modified		0
Unvested awards outstanding at September 30, 2019	$ 165.87	$ 165.87
Other 2019 Acquisitions | Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock
Number of Shares
Awards granted	9,394
Other 2019 Acquisitions | Service Period | Liability Classified Award | Cash-Settled Award | Restricted Stock Units
Number of Shares
Awards granted	7,280
Other 2019 Acquisitions | Performance Target | Equity Classified Award | Equity-Settled Award | Restricted Stock
Number of Shares
Awards granted	9,393
2019 Acquisitions | Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock Units
Number of Shares
Awards granted		21,933

STOCK-BASED COMPENSATION (Res_2

STOCK-BASED COMPENSATION (Restricted Stock and Restricted Stock Units Additional Information) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Liability associated with RSUs	$ 13,427	$ 13,427	$ 9,920
Service Period | Equity Classified Award | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	1,540	$ 1,540
Weighted-average remaining requisite service period		2 years 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]
Unrecognized compensation expense	70,990	$ 70,990
Weighted-average remaining requisite service period		2 years 8 months 12 days
Service Period | Liability Classified Award | Cash-Settled Award | Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	28,764	$ 28,764
Weighted-average remaining requisite service period		2 years 2 months 12 days
Performance Target | Equity Classified Award | Equity-Settled Award | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense	1,041	$ 1,041
Weighted-average remaining requisite service period		3 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]
Unrecognized compensation expense	0	$ 0
Deferred compensation due to employees | 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	$ 13,427	$ 13,427	$ 9,920
Other 2019 Acquisitions | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated future operating results, period	12 months
Other 2019 Acquisitions | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated future operating results, period	24 months

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule of Components and Changes in Income Tax Expense (Benefit) and Respective Balance Sheet Items [Line Items]
Effective tax rate	16.20%	0.60%	13.10%	(5.40%)
Excess tax benefit	$ 4,228	$ 6,067	$ 20,482	$ 16,197
Net deferred tax asset/(liability) resulting from the change in tax status of foreign subsidiaries		(252)		25,088
Tax Cuts and Jobs Act
Schedule of Components and Changes in Income Tax Expense (Benefit) and Respective Balance Sheet Items [Line Items]
Provisional income tax expense		$ 7,053		$ 4,896

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator for basic and diluted earnings per share:
Net income	$ 67,002	$ 58,777	$ 60,754	$ 65,618	$ 50,255	$ 64,418	$ 186,533	$ 180,291
Numerator for basic and diluted earnings per share	$ 67,002			$ 65,618			$ 186,533	$ 180,291
Denominator:
Weighted average common shares for basic earnings per share	54,877,666			53,851,865			54,603,903	53,485,339
Net effect of dilutive stock options, restricted stock units and restricted stock awards	2,966,689			3,111,002			2,963,436	3,114,299
Weighted average common shares for diluted earnings per share	57,844,355			56,962,867			57,567,339	56,599,638
Net income per share:
Basic (in dollars per share)	$ 1.22			$ 1.22			$ 3.42	$ 3.37
Diluted (in dollars per share)	$ 1.16			$ 1.15			$ 3.24	$ 3.19
Anti-dilutive options not included in the calculation (in shares)	143,617			157,316			112,757	121,896

COMMITMENTS AND CONTINGENCIES C

COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Details) - Office Space Purchase Commitment $ in Thousands	3 Months Ended
	Sep. 30, 2019USD ($)
Belarus
Other Commitments [Line Items]
Total commitment amount	$ 22,680
Ukraine
Other Commitments [Line Items]
Total commitment amount	48,900
Other noncurrent assets | Belarus
Other Commitments [Line Items]
Amount paid	1,000
Other noncurrent assets | Ukraine
Other Commitments [Line Items]
Amount paid	$ 12,000

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Operating profit	$ 80,565	$ 64,560	$ 218,105	$ 167,494
North America
Segment Reporting Information [Line Items]
Segment revenues	358,987	280,838	1,000,715	769,137
Operating profit	79,310	60,763	213,114	155,944
Europe
Segment Reporting Information [Line Items]
Segment revenues	205,123	171,482	596,798	516,320
Operating profit	27,550	28,871	87,014	84,329
Russia
Segment Reporting Information [Line Items]
Segment revenues	24,164	16,208	63,945	53,374
Operating profit	5,524	543	11,765	8,211
Operating Segments
Segment Reporting Information [Line Items]
Segment revenues	588,274	468,528	1,661,458	1,338,831
Operating profit	$ 112,384	$ 90,177	$ 311,893	$ 248,484

SEGMENTS INFORMATION (Major Cus

SEGMENTS INFORMATION (Major Customers) (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Revenue, Segment Benchmark [Member] | Operating Segments
Revenue, Major Customer [Line Items]
Number of customers	0	0	0	0
Accounts Receivable | Billed Revenues
Revenue, Major Customer [Line Items]
Number of customers			0		0
Accounts Receivable | Unbilled Revenues
Revenue, Major Customer [Line Items]
Number of customers			0		0

SEGMENTS INFORMATION (Reconcili

SEGMENTS INFORMATION (Reconciliation of Segment Revenues to Consolidated Revenues and Segment Operating Profit to Consolidated Income Before Provision for/(Benefit from) Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 588,103	$ 468,186	$ 1,661,023	$ 1,337,981
Segment Reporting Information [Line Items]
Income from operations	80,565	64,560	218,105	167,494
Stock-based compensation expense			(53,024)	(46,736)
Depreciation and amortization expense	(11,127)	(9,319)	(32,355)	(26,457)
Interest and other income, net	2,509	1,941	6,775	2,442
Foreign exchange (loss)/gain	(3,105)	(514)	(10,151)	1,069
Income before provision for income taxes	79,969	65,987	214,729	171,005
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Segment revenues	588,274	468,528	1,661,458	1,338,831
Segment Reporting Information [Line Items]
Income from operations	112,384	90,177	311,893	248,484
Unallocated amounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Segment revenues	(171)	(342)	(435)	(850)
Segment Reporting Information [Line Items]
Other income included in segment revenues	(171)	(342)	(435)	(850)
Stock-based compensation expense	(15,471)	(15,330)	(53,024)	(46,736)
Non-corporate taxes	(3,960)	(2,063)	(8,126)	(7,041)
Professional fees	(1,502)	(1,420)	(3,826)	(4,736)
Depreciation and amortization expense	(2,585)	(2,011)	(7,328)	(5,754)
Bank charges	(645)	(782)	(1,937)	(1,950)
One-time charges and other acquisition-related expenses	(1,142)	(155)	(2,503)	(2,016)
Other operating expenses	$ (6,343)	$ (3,514)	$ (16,609)	$ (11,907)

SEGMENTS INFORMATION (Physical

SEGMENTS INFORMATION (Physical Location and Values of Long-Lived Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 115,321	$ 102,646
Belarus
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	48,521	50,085
Ukraine
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	16,077	8,433
United States
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	13,934	13,101
Russia
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	12,514	9,902
India
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	6,742	7,019
Hungary
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	3,329	3,168
China
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	3,132	2,651
Poland
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	2,900	2,637
Other
Long-Lived Assets by Geographical Areas [Line Items]
Long-lived assets	$ 8,172	$ 5,650

SEGMENTS INFORMATION (Revenue_2

SEGMENTS INFORMATION (Revenues by Customer Location) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 588,103	$ 468,186	$ 1,661,023	$ 1,337,981
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	340,803	266,065	959,471	736,579
United Kingdom
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	74,992	50,482	209,773	152,315
Switzerland
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	38,781	35,524	110,378	105,396
Russia
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	23,668	15,609	62,020	51,930
Netherlands
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	22,161	17,031	63,816	51,934
Germany
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	20,940	20,732	59,716	60,331
Canada
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	17,582	18,008	50,339	51,391
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 49,176	$ 44,735	$ 145,510	$ 128,105