Syneos Health (SYNH) 10-K 17 Feb 22 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 10, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity File Number	001-36730
Entity Registrant Name	SYNEOS HEALTH, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-3403111
Entity Address, Address Line One	1030 Sync Street
Entity Address, City or Town	Morrisville
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27560-5468
City Area Code	919
Local Phone Number	876-9300
Title of 12(b) Security	Class A Common Stock, par value $0.01 per share
Trading Symbol	SYNH
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 9,235,907,535
Entity Common Stock, Shares Outstanding		104,221,138
Documents Incorporated by Reference	Portions of the registrant’s Proxy Statement for its 2022 Annual Meeting of Stockholders are incorporated by reference into Part III hereof
Entity Central Index Key	0001610950
Auditor Name	Deloitte & Touche LLP
Auditor Location	Raleigh, North Carolina
Auditor Firm ID	34

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue	$ 5,212,970	$ 4,415,777	$ 4,675,815
Costs and operating expenses:
Direct costs (exclusive of depreciation and amortization)	3,994,484	3,398,142	3,645,905
Selling, general, and administrative expenses	570,765	472,726	507,556
Restructuring and other costs	22,816	29,414	42,135
Depreciation	73,832	70,185	76,532
Amortization	161,793	152,167	165,933
Total operating expenses	4,823,690	4,122,634	4,438,061
Income from operations	389,280	293,143	237,754
Total other expense, net:
Interest income	(111)	(265)	(7,542)
Interest expense	79,252	91,145	129,820
Loss (gain) on extinguishment of debt	3,612	1,581	(10,395)
Other (income) expense, net	(8,633)	(2,976)	24,162
Total other expense, net	74,120	89,485	136,045
Income before provision for income taxes	315,160	203,658	101,709
Income tax expense (benefit)	80,329	10,871	(29,549)
Net income	$ 234,831	$ 192,787	$ 131,258
Earnings per share:
Basic (USD per share)	$ 2.26	$ 1.85	$ 1.27
Diluted (USD per share)	$ 2.24	$ 1.83	$ 1.25
Weighted average common shares outstanding:
Basic (in shares)	103,872	104,168	103,618
Diluted (in shares)	105,065	105,465	105,005

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 234,831	$ 192,787	$ 131,258
Unrealized gain (loss) on derivative instruments, net of income tax expense (benefit) of $5,599, $(1,394), and $(2,122), respectively	16,140	(3,925)	(7,596)
Foreign currency translation adjustments, net of income tax (benefit) expense of $(1,472), $1,354, and $0, respectively	(24,957)	34,717	24,198
Comprehensive income	$ 226,014	$ 223,579	$ 147,860

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Income tax expense (benefit) related to unrealized gain (loss) on derivative instruments recorded in other comprehensive loss	$ 5,599	$ (1,394)	$ (2,122)
Other comprehensive expense (benefit), foreign currency translation adjustment, tax	$ (1,472)	$ 1,354	$ 0

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash, cash equivalents, and restricted cash	$ 106,475	$ 272,173
Accounts receivable and unbilled services, net	1,524,890	1,344,781
Prepaid expenses and other current assets	135,091	121,058
Total current assets	1,766,456	1,738,012
Property and equipment, net	222,657	216,200
Operating lease right-of-use assets	209,408	223,285
Goodwill	4,956,015	4,776,178
Intangible assets, net	854,067	933,525
Deferred income tax assets	35,387	35,059
Other long-term assets	193,103	141,047
Total assets	8,237,093	8,063,306
Current liabilities:
Accounts payable	107,535	113,684
Accrued expenses	614,441	611,042
Deferred revenue	868,455	793,068
Current portion of operating lease obligations	43,058	42,082
Current portion of finance lease obligations	20,627	17,455
Total current liabilities	1,654,116	1,577,331
Long-term debt	2,775,721	2,902,054
Operating lease long-term obligations	205,798	221,760
Finance lease long-term obligations	34,181	31,522
Deferred income tax liabilities	78,062	20,216
Other long-term liabilities	76,660	68,311
Total liabilities	4,824,538	4,821,194
Commitments and contingencies (Note 17)
Shareholders’ equity:
Preferred stock, $0.01 par value; 30,000 shares authorized, 0 shares issued and outstanding as of December 31, 2021 and 2020
Common stock, $0.01 par value; 600,000 shares authorized, 103,764 and 103,935 shares issued and outstanding as of December 31, 2021 and 2020, respectively	1,038	1,039
Additional paid-in capital	3,474,088	3,461,747
Accumulated other comprehensive loss, net of taxes	(49,618)	(40,801)
Accumulated deficit	(12,953)	(179,873)
Total shareholders’ equity	3,412,555	3,242,112
Total liabilities and shareholders’ equity	$ 8,237,093	$ 8,063,306

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock par value (USD per share)	$ 0.01	$ 0.01
Preferred stock shares authorized (in shares)	30,000,000	30,000,000
Preferred stock shares issued (in shares)	0	0
Preferred stock shares outstanding (in shares)	0	0
Common stock par value (USD per share)	$ 0.01	$ 0.01
Common stock shares authorized (in shares)	600,000,000	600,000,000
Common stock shares issued (in shares)	103,764,000	103,935,000
Common stock shares outstanding (in shares)	103,763,635	103,934,738

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 234,831	$ 192,787	$ 131,258
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	235,625	222,352	242,465
Share-based compensation	65,204	58,491	55,193
Provision for doubtful accounts	367	695	1,897
Provision for (benefit from) deferred income taxes	46,522	(3,839)	(40,069)
Foreign currency transaction adjustments	(5,928)	4,148	11,166
Fair value adjustment of contingent obligations	(597)	(3,664)	17,260
Gain on sale of business		(7,133)
Loss (gain) on extinguishment of debt	3,612	1,581	(10,395)
Other non-cash items	7,789	1,765	2,766
Changes in operating assets and liabilities, net of effect of acquisitions:
Accounts receivable, unbilled services, and deferred revenue	(109,364)	16,316	(120,389)
Accounts payable and accrued expenses	24,620	(2,561)	28,316
Other assets and liabilities	(52,403)	(55,445)	(987)
Net cash provided by operating activities	450,278	425,493	318,481
Cash flows from investing activities:
Payments related to acquisitions of businesses, net of cash acquired	(278,920)	(456,455)	(712)
Proceeds from notes receivable from divestiture	5,000
Proceeds from sale of business		17,970
Purchases of property and equipment	(56,841)	(50,010)	(63,973)
Investments in unconsolidated affiliates	(5,741)	(15,589)	(16,976)
Loan to unconsolidated affiliate	(3,844)
Net cash used in investing activities	(340,346)	(504,084)	(81,661)
Cash flows from financing activities:
Proceeds from issuance of long-term debt, net of discount	494,505	600,000	582,000
Payments of debt financing costs	(1,008)	(9,570)	(2,636)
Repayments of long-term debt	(727,277)	(327,294)	(437,936)
Proceeds from accounts receivable financing agreement	100,000	31,600	127,815
Repayments of accounts receivable financing agreement		(6,600)	(22,400)
Proceeds from revolving line of credit	80,000	300,000
Repayments of revolving line of credit	(80,000)	(300,000)
Redemption of Senior Notes and associated breakage fees			(418,112)
Payments of contingent consideration related to acquisitions	7,197	26,634	178
Payments of finance leases	(15,774)	(16,434)	(14,493)
Payments for repurchases of common stock	(117,521)	(70,151)	(56,716)
Proceeds from exercises of stock options	28,148	24,568	40,322
Payments related to tax withholdings for share-based compensation	(31,453)	(21,220)	(13,135)
Net cash (used in) provided by financing activities	(277,577)	178,265	(215,469)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	1,947	8,810	(13,594)
Net change in cash, cash equivalents, and restricted cash	(165,698)	108,484	7,757
Cash, cash equivalents, and restricted cash - beginning of period	272,173	163,689	155,932
Cash, cash equivalents, and restricted cash - end of period	$ 106,475	$ 272,173	$ 163,689

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, AdjustmentAccumulated Deficit
Balance at beginning of period at Dec. 31, 2018	$ 2,856,144	$ 1,034	$ 3,402,638	$ (88,195)	$ (459,333)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchases of common stock		(13)	(43,515)		(13,188)
Issuances of common stock		18	27,155
Share-based compensation			55,193
Unrealized gain (loss) on derivative instruments, net of taxes	(7,596)
Foreign currency translation adjustment, net of taxes	24,198			24,198
Net income	131,258
Balance at end of period at Dec. 31, 2019	3,029,654	1,039	3,441,471	(71,593)	(341,263)
Balance at end of period (Accounting Standards Update 2016-13) at Dec. 31, 2019						$ (2,771)	$ (2,771)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on derivative instruments, net of taxes	(7,596)
Adjusted beginning balance	2,856,144				(459,333)
Repurchases of common stock		(13)	(41,512)		(28,626)
Issuances of common stock		13	3,297
Share-based compensation			58,491
Unrealized gain (loss) on derivative instruments, net of taxes	(3,925)
Foreign currency translation adjustment, net of taxes	34,717			34,717
Net income	192,787
Balance at end of period at Dec. 31, 2020	3,242,112	1,039	3,461,747	(40,801)	(179,873)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on derivative instruments, net of taxes	(3,925)
Adjusted beginning balance	3,026,883				(344,034)
Repurchases of common stock		(15)	(49,595)		(67,911)
Issuances of common stock		14	(3,268)
Share-based compensation			65,204
Unrealized gain (loss) on derivative instruments, net of taxes	16,140
Foreign currency translation adjustment, net of taxes	(24,957)			(24,957)
Net income	234,831
Balance at end of period at Dec. 31, 2021	3,412,555	$ 1,038	$ 3,474,088	$ (49,618)	(12,953)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized gain (loss) on derivative instruments, net of taxes	16,140
Adjusted beginning balance	$ 3,242,112				$ (179,873)

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	1. Basis of Presentation and Summary of Significant Accounting Policies Principal Business Syneos Health, Inc. (the “Company”) is a global provider of end-to-end biopharmaceutical outsourcing solutions. The Company operates under two reportable segments, Clinical Solutions and Commercial Solutions, and derives its revenue through a suite of services designed to enhance its customers’ ability to successfully develop, launch, and market their products. The Company offers its solutions on both a standalone and integrated basis with biopharmaceutical development and commercialization services ranging from Phase I to IV clinical trial services to services associated with the commercialization of biopharmaceutical products. The Company’s customers include small, mid-sized, and large companies in the pharmaceutical, biotechnology, and medical device industries. Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ( “ ” Reclassification Certain previously reported amounts have been reclassified to conform to the current year presentation. COVID-19 Pandemic The ongoing COVID-19 pandemic and associated economic repercussions have significantly impacted, and are expected to continue to impact, the Company’s business and operations. The continued availability and effectiveness of vaccines may partially mitigate the risks around the continued spread of COVID-19, however, with the spread of COVID-19 variants, the ongoing impacts of the COVID-19 pandemic could adversely impact its business and results of operations. See Part I, Item 1A “Risk Factors” in this Annual Report on Form 10-K for further discussion of the potential impact of the pandemic on its business. Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenue and expenses for the periods presented in the financial statements. Examples of estimates and assumptions include, but are not limited to, determining the fair value of goodwill and intangible assets and their potential impairment, useful lives of tangible and intangible assets, useful lives of assets subject to leases, valuation of the Company’s right of use assets, allowances for doubtful accounts, potential future outcomes of events for which income tax consequences have been recognized in the Company’s consolidated financial statements or tax returns, valuation allowances for deferred tax assets, fair value of share-based compensation and its recognition period, loss contingencies, fair value of derivative instruments and related hedge effectiveness, fair value of contingent tax sharing obligations, and judgments related to revenue recognition, among others. In addition, estimates and assumptions are used in the accounting for acquisitions, including the fair value and useful lives of acquired tangible and intangible assets and the fair value of assumed liabilities. The Company evaluates its estimates and assumptions on an ongoing basis and bases its estimates on historical experience, current and expected future conditions, third-party evaluations, and various other assumptions that management believes are reasonable under the circumstances based on the information available to management at the time these estimates and assumptions are made. Actual results and outcomes may differ significantly from these estimates and assumptions. Acquisitions The Company accounts for acquisitions in accordance with ASC Topic 805, Business Combinations “ ” Foreign Currency Translation and Transactions For subsidiaries outside of the U.S. that operate in a local currency environment, revenue and expenses are translated to U.S. dollars at the monthly average rates of exchange prevailing during the period, assets and liabilities are translated at period-end exchange rates, and equity accounts are translated at historical exchange rates. The net effect of foreign currency translation adjustments is included in shareholders’ equity as a component of accumulated other comprehensive loss in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are the result of exchange rate changes during the period of time between the consummation and cash settlement of transactions denominated in currencies other than the functional currency. Foreign currency transaction gains and losses are recognized in earnings as incurred and are included in other (income) expense, net in the accompanying consolidated statements of income. Comprehensive Income Comprehensive income Cash and Cash Equivalents Cash and cash equivalents consist of demand deposits with banks and other financial institutions and highly liquid investments with an original maturity of three months or less at the date of purchase. Cash and cash equivalents are carried at cost, which approximates their fair value. Certain of the Company’s subsidiaries participate in a notional cash pooling arrangement to manage global liquidity requirements. As part of a master netting arrangement, the participants combine their cash balances in pooling accounts at the same financial institution with the ability to offset bank overdrafts of one participant against positive cash account balances held by another participant. Under the terms of the master netting arrangement, the financial institution has the right, ability, and intent to offset a positive balance in one account against an overdrawn amount in another account. Amounts in each of the accounts are unencumbered and unrestricted with respect to use. As such, the net cash balance related to this pooling arrangement is included in cash, cash equivalents, and restricted cash in the accompanying consolidated balance sheets. The Company’s net cash pool position consisted of the following as of December 31 (in thousands): 2021 2020 Gross cash position $ 179,160 $ 220,261 Less: cash borrowings (167,507 ) (204,647 ) Net cash position $ 11,653 $ 15,614 Restricted Cash Restricted cash represents cash and deposits held as security over bank deposits, lease guarantees, and insurance obligations that are restricted as to withdrawal or use. Restricted cash is classified as a current or long-term asset based on the timing and nature of when and how the cash is expected to be used or when the restrictions are expected to lapse. As of December 31, 2021 and 2020, restricted cash balances were $0.1 million and $0.3 million, respectively. Fair Value The Company records certain assets and liabilities at fair value in accordance with ASC Topic 820, Fair Value Measurement “ ” Level 1 – Unadjusted quoted prices in active markets for identical instruments; Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs or significant value-drivers are observable in active markets; and Level 3 – Model-derived valuations in which one or more significant inputs or significant value-drivers are unobservable, including internally developed models. Derivative Financial Instruments Interest Rate Swaps The Company uses interest rate swaps to manage exposure to variable interest rates on its debt obligations. The Company designates its interest rate swaps as cash flow hedges because they are executed to hedge the Company’s exposure to the variability in expected future cash flows that are attributable to changes in interest rates. Derivative financial instruments are measured at fair value and recognized in the accompanying consolidated balance sheets in prepaid expenses and other current assets, other long-term assets, accrued expenses, and other long-term liabilities, as disclosed in “ ” Foreign Exchange Forward The Company utilizes a foreign exchange forward in order to minimize monthly foreign currency remeasurement gains or losses on non-functional currency monetary balances. The Company did not designate the derivative as a hedge. All changes in the fair value of the foreign exchange forward are recorded in earnings every month to other (income) expense, net in the accompanying consolidated statements of income “ ” Allowance for Doubtful Accounts The Company maintains a credit approval process and makes judgments in connection with assessing its customers’ ability to pay for contracted services. Generally, the Company has the ability to limit credit exposure by discontinuing services in the event of non-payment. The Company monitors its customers’ credit worthiness and applies judgment in establishing a provision for estimated credit losses based on historical experience, the aging of receivables, and customer-specific circumstances that would affect the customers’ ability to pay for services rendered. Property and Equipment Property and equipment primarily consists of furniture, vehicles, software, office equipment, computer equipment, and lab equipment. Purchased and constructed property and equipment is initially recorded at historical cost plus the estimated value of any associated legally or contractually required retirement obligations. Property and equipment acquired in an acquisition are recorded based on the estimated fair value as of the acquisition date. The Company leases vehicles for certain sales representatives in the Commercial Solutions segment. These leases are classified and accounted for as leases in accordance with ASC Topic 842, Leases “ ” “ ” Property and equipment assets are depreciated using the straight-line method over the respective estimated useful lives as follows: Useful Life Buildings 39 years Furniture and fixtures 7 years Equipment 5 to 10 years Computer equipment and software 2 to 3 years Vehicles Lesser of lease term or the estimated economic life of the leased asset Leasehold improvements Lesser of remaining life of lease or the useful life of the asset Expenditures for repairs and maintenance are expensed as incurred and expenditures for major improvements that increase the functionality or extend the useful life of the asset are capitalized and depreciated over the estimated useful life of the asset. The Company capitalizes costs of computer software obtained for internal use and amortizes these costs on a straight-line basis over the estimated useful life of the product, not to exceed five years. Software cloud computing arrangements containing a software license are accounted for consistently with the acquisition of other software licenses. In the event such an arrangement does not contain a software license, the Company accounts for the arrangement as a service contract. The Company reviews property and equipment for impairment whenever facts and circumstances indicate that the carrying amounts of these assets might not be recoverable. For assessment purposes, property and equipment are grouped with other assets and liabilities at the lowest level that identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Recoverability of the carrying amount of an asset group is assessed by comparing its carrying amount to the estimated undiscounted future cash flows expected to be generated by the asset group. If the carrying value of the asset group exceeds its fair value, an impairment charge is recognized for the excess. Leases At inception, a contract contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In evaluating whether it has the right to control the use of an identified asset, the Company assesses whether they have the right to direct the use of the identified asset and to obtain substantially all of the economic benefit from the use of the identified asset. Right-of-use ( “ ” ’ ’ ’ Because most of the Company ’ The Company has agreements with lease and non-lease components, which are accounted for as a single lease component. Leases with a lease term of 12 months or less are not recorded on the balance sheet. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. Variable lease payment amounts that cannot be determined at the commencement of the lease, such as increases in lease payments based on changes in index rates, are not included in the right-of-use assets or liabilities. These variable lease payments are expensed as incurred. Goodwill and Intangible Assets Goodwill represents the excess of the purchase price over the estimated fair value of net assets acquired, including the amount assigned to identifiable intangible assets, in acquisitions. In accordance with ASC Topic 350, Intangibles Goodwill and Other The Company has assigned goodwill to four reporting units. The Company completed an annual impairment test as of October 1, 2021 for all of its reporting units, and concluded that there were no impairments. Intangible assets consist of customer relationships, acquired backlog, trade names, trademarks, patient communities, and acquired technologies. The Company amortizes intangible assets related to customer relationships, trade names, trademarks, patient communities, and acquired technologies on a straight-line basis over the estimated useful life of the asset. Intangible assets related to acquired backlog are amortized based on the Company’s expectations of the timing of when revenue associated with the backlog is expected to be recognized. The Company reviews intangible assets at the end of each reporting period to determine if facts and circumstances indicate that the useful life is shorter than originally estimated or that the carrying amount of the assets might not be recoverable. If such facts and circumstances exist, the Company assesses the recoverability of identified assets by comparing the projected undiscounted cash flows associated with the related asset or group of assets to their respective carrying amounts. Impairments, if any, are based on the excess of the carrying amount over the fair value of those assets and occur in the period in which the impairment determination is made. The weighted average estimated useful lives of the Company’s intangible assets were as follows as of December 31: 2021 2020 Customer relationships 9.8 years 9.9 years Acquired backlog 2.6 years 2.6 years Trade names and trademarks 5.5 years 5.5 years Intellectual property (medical patent) n/a 9.0 years Patient communities 6.0 years n/a Acquired technologies 6.0 years n/a No intangible asset impairment charges were recorded for the years ended December 31, 2021 or 2020. For additional information regarding the carrying values of intangible assets, see “ ” Contingencies In the normal course of business, the Company periodically becomes involved in various proceedings and claims, including investigations, disputes, litigations, and regulatory matters that are incidental to its business. The Company evaluates the likelihood of an unfavorable outcome of all legal and regulatory matters and records accruals for probable loss contingencies for which the amount of the loss can be reasonably estimated. Gain contingencies are not recognized until realized. Legal fees are expensed as incurred. Because these matters are inherently unpredictable, and unfavorable developments or resolutions can occur, assessing contingencies is highly subjective and requires judgments about future events. These judgments and estimates are based, among other factors, on the status of the proceedings, the merits of the Company’s defenses, and the consultation with in-house and external counsel. The Company regularly reviews contingencies to determine whether its accruals and related disclosures are adequate. Although the Company believes that it has substantial defenses in these matters, the amount of losses incurred as a result of actual outcomes may differ significantly from the Company’s estimates. Revenue Recognition In accordance with ASC Topic 606, Revenue from Contracts with Customers A performance obligation is a promise (or a combination of promises) in a contract to transfer distinct goods or services to a customer and is the unit of accounting under ASC 606 for the purposes of revenue recognition. A contract’s transaction price is allocated to each performance obligation and is recognized as revenue, when, or as, each performance obligation is satisfied. The majority of the Company’s Clinical Solutions segment contracts have a single performance obligation because the promise to transfer individual services is not separately identifiable from other promises in the contracts, and therefore, is not distinct. For contracts with multiple performance obligations, the contract’s transaction price is allocated to each performance obligation using the best estimate of the standalone selling price of each distinct good or service in the contract. The majority of the Company’s revenue arrangements are service contracts that range in duration from a few months to several years. Substantially all of the Company’s performance obligations, and associated revenue, are transferred to the customer over time. The Company generally receives compensation based on measuring progress toward completion using anticipated project budgets for direct labor and prices for each service offering. The Company is also reimbursed for certain third-party pass-through and out-of-pocket costs. In addition, in certain instances a customer contract may include forms of variable consideration such as incentive fees, volume rebates or other provisions that can increase or decrease the transaction price. This variable consideration is generally awarded upon achievement of certain performance metrics, program milestones or cost targets. For the purposes of revenue recognition, variable consideration is assessed on a contract-by-contract basis and the amount included in the transaction price is estimated based on the Company’s anticipated performance and consideration of all information that is reasonably available. Variable consideration is recognized as revenue if and when it is deemed probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved in the future. Most of the Company’ s contracts can be terminated by the customer without cause with a notice period that generally ranges from 30 to 90 day s . In the event of termination, the Company’ s contracts generally provide that the customer pay the Company for: (i) fees earned through the termination date; (ii) fees and expenses for winding down the project, which include both fees incurred and actual expenses; (iii) non-cancellable expenditures; and (iv) in some cases, a fee to cover a portion of the remaining professional fees on the project . The Company’s long-term clinical trial contracts contain implied substantive termination penalties because of the significant wind-down cost of terminating a clinical trial. These provisions for termination penalties result in these types of contracts being treated as long-term for revenue recognition purposes. Changes in the scope of work are common, especially under long-term contracts, and generally result in a change in the total contract transaction price. If the customer does not agree to a contract modification, the Company could bear the risk of cost overruns. Most of the Company’s contract modifications are for services that are not distinct from the services under the existing contract due to the significant integration service provided in the context of the contract and therefore result in a cumulative catch-up adjustment to revenue at the date of contract modification. Capitalized Costs The Company capitalizes certain costs associated with commissions and bonuses paid to its employees in the Clinical Solutions segment because these costs are incurred in obtaining contracts that have a term greater than one year. Capitalized costs are included in prepaid expenses and other current assets and other long-term assets in the accompanying consolidated balance sheets. The Company amortizes these costs in a manner that is consistent with the pattern of revenue recognition described below. The Company expenses costs to obtain contracts that have a term of one year or less. Clinical Solutions The Company’s Clinical Solutions segment provides solutions to address the clinical development needs of customers. The Company provides total biopharmaceutical program development through its full-service platform, while also providing discrete services for any part of a clinical trial, primarily through functional service provider, Early Stage, and Real World and Late Phase (“RWLP”) services. The services provided via the full-service platform and RWLP platforms generally span several years and a significant benefit to the customer is provided by integrating the services provided by the Company’s employees as well as those performed by third parties. Because the Company’s full-service platform provides a significant integration service to the customer, these contracts contain a single performance obligation. Revenue is recognized over time using an input measure of progress. The input measure reflects costs (including investigator payments and pass-through costs) incurred to date relative to total estimated costs to complete (“cost-to-cost measure of progress”). Under the cost-to-cost measure of progress methodology, revenue is recorded proportionally to costs incurred. Contract costs principally include direct labor, investigator payments, and pass-through costs. The estimate of total estimated costs at completion requires significant judgment. Contract estimates are based on various assumptions to project future outcomes of events that often span several years. These estimates are reviewed periodically and any adjustments are recognized on a cumulative catch-up basis in the period they become known. The remaining service offerings within the Clinical Solutions segment are generally short-term, month-to-month contracts, time and materials basis contracts, or provide a series of distinct services that are substantially the same and have the same pattern of transfer to the customer (“series”). As such, revenue for these service offerings is generally recognized as services are performed for the amount the Company estimates it is entitled to for the period. Commercial Solutions The Company’s Commercial Solutions segment provides a broad suite of complementary commercialization services including Deployment Solutions, communications (advertising and public relations), and consulting services. Deployment Solutions contracts offer outsourced services to promote commercial products on behalf of a customer. The remaining Commercial Solutions contracts are generally short-term, month-to-month contracts or time and materials contracts. As such, Commercial Solutions revenue is generally recognized as services are performed for the amount of consideration the Company estimates it is entitled to for the period. For contracts billed on a fixed price basis, revenue is recognized over time based on the proportion of labor costs expended to total labor costs expected to complete the contract. Accounts Receivable, Unbilled Services, and Deferred Revenue Accounts receivable are recorded at net realizable value. Unbilled accounts receivable arise when services have been rendered for which revenue has been recognized but the customers have not been billed. Contractual provisions and payment schedules may or may not correspond to the timing of the performance of services under the contract. Unbilled services include contract assets, under which the right to bill the customer is subject to factors other than the passage of time. These amounts may not exceed their net realizable value. Contract assets are generally classified as current. Deferred revenue is a contract liability that consists of customer payments received in advance of performance and billings in excess of revenue recognized, net of revenue recognized from the balance at the beginning of the period. Timing of Billing and Performance Differences in the timing of revenue recognition and associated billings and cash collections result in recording of billed accounts receivable, unbilled accounts receivable (including contract assets), and deferred revenue on the consolidated balance sheet. Amounts are billed as work progresses in accordance with agreed-upon contractual terms either at periodic intervals or upon achievement of contractual milestones. Billings generally occur subsequent to revenue recognition, resulting in recording unbilled accounts receivable in instances where the right to bill is contingent solely on the passage of time (e.g., in the following month), and contract assets in instances where the right to bill is associated with achievement of a milestone. Reimbursable Out-of-Pocket Expenses The Company incurs and is reimbursed by its customers for certain costs, including fees paid to principal investigators and for other out-of-pocket costs (such as travel expenses for the Company’s clinical monitors and sales representatives). The Company includes these costs in total operating expenses, and the related reimbursements in revenue, as the Company is the principal in the applicable arrangements and is responsible for fulfilling the promise to provide the specified services. Share-Based Compensation The Company measures and recognizes compensation expense related to all share-based awards based on the estimated fair value of the awards. The fair value of restricted stock and stock unit awards is measured on the grant date based on the fair market value of the Company’s common stock. Share-based compensation expense is recognized on a straight-line basis over the shorter of the requisite service period or the vesting term. For awards with performance conditions, stock-based compensation expense is recognized when the achievement of each individual performance target becomes probable, and the number of shares expected to vest is adjusted for the weighted probability of attainment of the relevant performance targets. Forfeitures are accounted for as they occur. All excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards, if applicable) are recognized as income tax expense or benefit in the consolidated statements of income. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. The Company also recognizes excess tax benefits regardless of whether the benefit reduces taxes payable in the current period. Income Taxes The majority of the Company’s U.S. subsidiaries file a consolidated U.S. federal income tax return, while certain U.S. subsidiaries, including recently acquired entities, may file separate U.S. federal tax returns. The Company’s subsidiaries in international jurisdictions file tax returns in their respective jurisdictions. The Company estimates its tax liability based on current tax laws in the statutory jurisdictions in which it operates. Accordingly, the impact of changes in income tax laws on deferred tax assets and deferred tax liabilities is recognized in earnings in the period during which such changes are enacted. The Company records deferred tax assets and liabilities based on temporary differences between the financial reporting basis and tax basis of the Company’s assets and liabilities at enacted tax rates expected to be in effect when the differences are realized or settled. Deferred income tax assets represent amounts available to reduce income taxes payable on taxable income in future years. Such assets arise because of temporary differences between the financial reporting and tax bases of assets and liabilities, as well as from net operating loss and tax credit carryforwards. The Company evaluates recoverability of these future tax deductions. The Company establishes a valuation allowance for deferred income tax assets when the Company believes it is more likely than not the assets will not be realized. The Company evaluates the recoverability of these future tax deductions by assessing future expected taxable income. In estimating future taxable income, the Company considers both positive and negative evidence, such as historical and forecasted results of operations, and implementation of prudent and feasible tax planning strategies. If the objectively verifiable negative evidence outweighs any available positive evidence (or the only available positive is subjective and cannot be verified), then a valuation allowance will likely be deemed necessary. If a valuation allowance is deemed to be unnecessary, such allowance is released and any related benefit is recognized in the period of the change. The Company recognizes a tax benefit from any uncertain tax positions only if they are more likely than not to be sustained upon examination based on the technical merits of the position. The Company evaluates uncertain tax positions pursuant to the more likely than not standard, and benefits related to such uncertain tax positions are recognized as the largest amount of benefit, determined on a cumulative probability basis, to be realized upon ultimate settlement of the position. Components of the reserve for uncertain tax positions are classified as either a current or a long-term liability in the accompanying consolidated balance sheets based on management’s expectation of future cash settlements. Judgment is required in determining what constitutes an uncertain tax position, as well as assessing the outcome of each tax position. The Company considers many factors when evaluating and estimating tax positions and tax benefits. In addition, the calculation of tax liabilities involves dealing with uncertainties in the application of complex tax regulations in domestic and foreign jurisdictions. If the calculation of the liability related to uncertain tax positions proves to be more or less than the ultimate settlement, a tax expense or tax benefit, respectively, would result. Unrecognized tax benefits are presented as either a reduction to a deferred tax asset or as a separate liability. Restructuring and Other Costs Restructuring and other costs primarily consist of one-time employee termination benefits, contract termination costs, and other costs associated with an exit or disposal activity. The Company accounts for restructuring costs in accordance with ASC Topic 420, Exit or Disposal Cost Obligations Earnings Per Share The Company determines earnings per share in accordance with ASC Topic 260, Earnings Per Share Subsequent Events The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The Company evaluated all events and transactions through the date that these financial statements were issued. Recently Adopted Accounting Standards In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-13 (“ASU 2016-13”), Financial Instruments - Credit Losses (Topic 326) to modify the impairment model to utilize an expected loss methodology in place of the previous incurred loss methodology and require consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The Company adopted ASU 2016-13 on January 1, 2020, and recorded the impact of the adoption through a cumulative-effect adjustment to accumulated deficit. for reporting periods beginning on January 1, 2020 are presented under ASU No. 2016-13, while prior period amounts continue to be reported and disclosed in accordance with the Company’s historical accounting treatment. Adoption of the new standard resulted in the recording of additional allowance for doubtful accounts of approximately $2.8 million as of January 1, 2020.

Financial Statement Details

Financial Statement Details	12 Months Ended
	Dec. 31, 2021
Text Block [Abstract]
Financial Statement Details	2. Financial Statement Details Accounts Receivable and Unbilled Services, net Accounts receivable and unbilled services (including contract assets), net of allowance for doubtful accounts, consisted of the following as of December 31 (in thousands): 2021 2020 Accounts receivable billed $ 873,265 $ 774,605 Accounts receivable unbilled 241,799 211,285 Contract assets 417,411 366,506 Less: Allowance for doubtful accounts (7,585 ) (7,615 ) Accounts receivable and unbilled services, net $ 1,524,890 $ 1,344,781 The following table summarizes the changes in the allowance for doubtful accounts (in thousands): Year Ended December 31, 2021 2020 2019 Balance at the beginning of the period $ (7,615 ) $ (5,381 ) $ (4,587 ) Impact from adoption of ASU 2016-13 — (2,771 ) — Current year provision (367 ) (695 ) (1,897 ) Write-offs, net of recoveries and the effects of foreign currency exchange 397 1,232 1,103 Balance at the end of the period $ (7,585 ) $ (7,615 ) $ (5,381 ) Accounts Receivable Factoring Arrangement The Company has an accounts receivable factoring agreement to sell certain eligible unsecured trade accounts receivable, at its option, without recourse, to an unrelated third-party financial institution for cash. For the years ended December 31, 2021 and 2020, the Company factored $129.1 million and $152.4 million, respectively, of trade accounts receivable on a non-recourse basis and received $128.9 million and $151.9 million, respectively, in cash proceeds from the sale. The fees associated with these transactions were insignificant. Property and Equipment, net Property and equipment, net of accumulated depreciation, consisted of the following as of December 31 (in thousands): 2021 2020 Software $ 159,736 $ 129,731 Leasehold improvements 96,188 94,596 Computer equipment 91,937 108,230 Vehicles 77,674 63,985 Office furniture, fixtures, and equipment 65,018 37,287 Buildings and land 5,692 5,211 Assets not yet placed in service 28,706 28,129 Property and equipment, gross 524,951 467,169 Less: Accumulated depreciation (302,294 ) (250,969 ) Property and equipment, net $ 222,657 $ 216,200 As of December 31, 2021 and 2020, the gross book value of vehicles under finance leases was $77.7 million and $64.0 million, respectively, and accumulated depreciation was $30.0 million and $20.5 million, respectively. For the years ended December 31, 2021 and 2020, amortization charges related to these assets, net of rebates, were $17.5 million and $15.8 million, respectively, and were included in depreciation on the accompanying consolidated statements of income. Goodwill and Intangible Assets The changes in carrying amount of goodwill by segment were as follows (in thousands): Clinical Solutions (a) Commercial Solutions (b) Total Balance as of December 31, 2019 $ 2,784,952 $ 1,565,428 $ 4,350,380 Acquisitions and divestitures (c) 418,619 (14,453 ) 404,166 Impact of foreign currency translation 12,764 8,868 21,632 Balance as of December 31, 2020 3,216,335 1,559,843 4,776,178 Acquisitions (d) 192,286 — 192,286 Impact of foreign currency translation and other (e) 40,078 (52,527 ) (12,449 ) Balance as of December 31, 2021 $ 3,448,699 $ 1,507,316 $ 4,956,015 (a) Accumulated impairment losses of $8.1 million associated with the Clinical Solutions segment were recorded prior to 2016 and related to the former Phase I Services segment, now a component of the Clinical Solutions segment. No impairment of goodwill was recorded for the years ended December 31, 2021, 2020, or 2019. (b) Accumulated impairment losses of $8.0 million associated with the Commercial Solutions segment were recorded prior to 2015 and related to the former Global Consulting segment, now a component of the Commercial Solutions segment. No impairment of goodwill was recorded for the years ended December 31, 2021, 2020, or 2019. (c) Amounts represent goodwill recognized in connection with the 2020 acquisitions of SHCR Holdings Corporation (“Synteract”) Illingworth Research Group™ (“Illingworth Research”) (d) Amount represents goodwill recognized in connection with the acquisitions of StudyKIK Corporation (“StudyKIK”) and RxDataScience, Inc. (“RxDataScience”), other insignificant acquisitions in 2021, and insignificant measurement period adjustments recognized in connection with the 2020 acquisitions of Synteract and Illingworth Research within the Clinical Solutions segment. (e) Includes $44.2 million reallocation of goodwill from the Commercial Solutions segment to the Clinical Solutions segment to reflect the transfer of the Kinapse Regulatory and Operations Consulting service lines to align with management reporting in 2021. Intangible assets, net consisted of the following (in thousands): December 31, 2021 December 31, 2020 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Customer relationships $ 1,547,925 $ (811,542 ) $ 736,383 $ 1,518,081 $ (685,021 ) $ 833,060 Acquired backlog 175,826 (154,475 ) 21,351 174,180 (132,733 ) 41,447 Trade names and trademarks 55,728 (28,806 ) 26,922 52,475 (21,817 ) 30,658 Intellectual property (medical patent) — — — 30,028 (1,668 ) 28,360 Patient communities 45,100 (2,192 ) 42,908 — — — Acquired technologies 27,800 (1,297 ) 26,503 — — — Intangible assets, net $ 1,852,379 $ (998,312 ) $ 854,067 $ 1,774,764 $ (841,239 ) $ 933,525 The future estimated amortization expense for intangible assets as of December 31, 2021 is expected to be as follows (in thousands): Year Ended December 31, 2022 $ 162,193 2023 153,334 2024 146,487 2025 132,512 2026 110,597 2027 and thereafter 148,944 Total $ 854,067 Accrued Expenses Accrued expenses consisted of the following as of December 31 (in thousands): 2021 2020 Professional fees, investigator fees, and pass-through costs $ 283,432 $ 231,638 Compensation, including bonuses, fringe benefits, and payroll taxes 215,386 255,042 Income and other taxes 25,723 28,890 Rebates to customers 22,367 22,528 Restructuring and other costs, current portion 6,657 5,830 Contingent obligations, current 3,397 4,327 Interest rate swaps - current 1,827 17,045 Other liabilities 55,652 45,742 Total accrued expenses $ 614,441 $ 611,042 Accumulated Other Comprehensive Loss, Net of Taxes Accumulated other comprehensive loss, net of taxes, consisted of the following (in thousands): Year Ended December 31, 2021 2020 Beginning balance $ (40,801 ) $ (71,593 ) Derivative Instruments: Beginning balance (18,761 ) (14,836 ) Other comprehensive gain (loss) before reclassifications 2,963 (20,446 ) Reclassification adjustments 13,177 16,521 Ending balance (2,621 ) (18,761 ) Foreign Currency Translation: Beginning balance (22,040 ) (56,757 ) Other comprehensive (loss) income before reclassifications (24,957 ) 34,717 Ending balance (46,997 ) (22,040 ) Accumulated other comprehensive loss, net of taxes $ (49,618 ) $ (40,801 ) Changes in accumulated other comprehensive loss consisted of the following (in thousands): Year Ended December 31, 2021 2020 2019 Unrealized loss on derivative instruments: Unrealized gain (loss) during period, before taxes $ 4,084 $ (27,647 ) $ (14,306 ) Income tax expense (benefit) 1,121 (7,201 ) (2,777 ) Unrealized gain (loss) during period, net of taxes 2,963 (20,446 ) (11,529 ) Reclassification adjustment, before taxes 17,655 22,328 4,588 Income tax expense 4,478 5,807 655 Reclassification adjustment, net of taxes 13,177 16,521 3,933 Total unrealized gain (loss) on derivative instruments, net of taxes 16,140 (3,925 ) (7,596 ) Foreign currency translation adjustments: Foreign currency translation adjustments, before taxes (26,429 ) 36,071 24,198 Income tax (benefit) expense (1,472 ) 1,354 — Foreign currency translation adjustments, net of taxes (24,957 ) 34,717 24,198 Total other comprehensive (loss) income, net of taxes $ (8,817 ) $ 30,792 $ 16,602 Other (Income) Expense, Net Other (income) expense, net consisted of the following (in thousands): Year Ended December 31, 2021 2020 2019 Net realized foreign currency loss $ 2,190 $ 3,175 $ 11,853 Net unrealized foreign currency (gain) loss (5,928 ) 4,147 11,166 Gain on sale of business — (7,133 ) — Equity investment (income) expense (1,950 ) (3,745 ) 261 Other, net (2,945 ) 580 882 Total other (income) expense, net $ (8,633 ) $ (2,976 ) $ 24,162 Supplemental disclosure of cash flow information The following table provides details of supplemental cash flow information (in thousands): Year Ended December 31, 2021 2020 2019 Cash paid for income taxes, net of refunds $ 35,100 $ 23,400 $ 12,200 Cash paid for interest (excluding finance leases) 63,952 83,690 129,756 Supplemental disclosure of noncash investing and financing activities Non-cash investment to acquire certain intellectual property rights from a customer in lieu of cash payment for services rendered — 27,300 — Fair value of contingent consideration related to acquisitions 19,158 — — Change in property and equipment included in liabilities 1,753 11,684 5,977 Vehicles acquired through finance lease agreements 28,994 20,203 37,701

Acquisitions, Divestitures, and

Acquisitions, Divestitures, and Investments	12 Months Ended
	Dec. 31, 2021
Business Combinations [Abstract]
Acquisitions, Divestitures, and Investments	3. Acquisitions, Divestitures, and Investments StudyKIK Acquisition On September 13, 2021, the Company completed the acquisition of StudyKIK, a leading clinical trial recruitment and retention company, expanding the Company’s portfolio of patient-direct, technology-enabled solutions. The total purchase consideration was $203.6 million (net of cash acquired of $1.0 million). The Company recognized $115.3 million of goodwill and $91.8 million of intangible assets. The remainder of consideration was attributed to other net assets, primarily related to net working capital. The purchase price has been allocated to the tangible assets and identifiable intangible assets acquired and liabilities assumed based upon their fair values. The excess of the purchase price over the tangible and intangible assets acquired and liabilities assumed has been recorded as goodwill. Goodwill is attributable to the acquired workforce as well as future synergies and is not deductible for income tax purposes. The operating results from the acquisition have been included in the Company’s Clinical Solutions segment from the date of acquisition. The following table summarizes the fair values of identified intangible assets and their respective useful lives (dollars in thousands): Estimated Fair Value Estimated Useful Life Customer relationships $ 22,300 6 years Acquired backlog 1,800 1.25 years Trade name 2,700 6 years Patient communities 45,100 6 years Acquired technologies 19,900 6 years Total intangible assets $ 91,800 RxDataScience Acquisition On October 6, 2021, the Company completed the acquisition of RxDataScience, a specialist organization that helps biopharmaceutical customers solve challenging problems through advanced analytics, data management, and artificial intelligence. The total purchase consideration was $67.5 million (net of cash acquired of $2.4 million). The Company recognized $52.9 million of goodwill and $18.0 million of intangible assets. The remainder of consideration was attributed to other net assets, primarily related to net working capital. Refer to “Note 16 – Related-Party Transactions” for further information. The purchase price has been allocated to the tangible assets and identifiable intangible assets acquired and liabilities assumed based upon their fair values. The excess of the purchase price over the tangible and intangible assets acquired and liabilities assumed has been recorded as goodwill. Goodwill is attributable to the acquired workforce as well as future synergies and is not deductible for income tax purposes. The operating results from the acquisition have been included in the Company’s Clinical Solutions segment from the date of acquisition. The Company’s assessments of fair value and the purchase price allocations related to these 2021 acquisitions are preliminary and further adjustments may be necessary as additional information related to the fair values of assets acquired and liabilities assumed is assessed during the measurement period (up to one year from the respective acquisition dates). Synteract Acquisition On December 9, 2020, the Company completed the acquisition of Synteract, effected through the purchase of 100% of the outstanding shares of Synteract for approximately $385.5 million in cash (net of approximately $28.0 million of cash acquired), which included payment of $1.0 million during the first quarter of 2021. Synteract is a contract research organization focused on the emerging biopharmaceutical industry, strengthening the Company’s position in the small to mid- sized (“SMID”) ategory. Allocation of Consideration Transferred The following table summarizes the estimated fair value of the net assets acquired at the date of the acquisition: Assets acquired: Cash and cash equivalents $ 28,028 Accounts receivable and unbilled services 39,723 Prepaid expenses and other current assets 2,160 Property and equipment 3,978 Operating lease right-of-use assets 10,839 Other identifiable intangible assets 56,400 Goodwill 363,733 Other assets 4,121 Total assets acquired 508,982 Liabilities assumed: Accounts payable and accrued expenses 25,623 Deferred revenue 45,272 Operating lease obligations 15,693 Deferred income taxes, net 7,754 Other liabilities 1,126 Total liabilities assumed 95,468 Net assets acquired $ 413,514 The purchase price has been allocated to the tangible assets and identifiable intangible assets acquired and liabilities assumed based upon their fair values. The excess of the purchase price over the tangible and intangible assets acquired and liabilities assumed has been recorded as goodwill. Goodwill is attributable to the acquired workforce as well as future synergies and is not deductible for income tax purposes. The operating results from the acquisition of Synteract have been included in the Company’s Clinical Solutions segment from the date of acquisition. The following table summarizes the fair value of identified intangible assets and their respective useful lives at the date of the acquisition (dollars in thousands): Estimated Fair Value Estimated Useful Life Acquired backlog $ 37,200 4 years Trade name 19,200 8 years Total intangible assets $ 56,400 Illingworth Research Group Acquisition On December 17, 2020, the Company completed the acquisition of Illingworth Research, a leading provider of clinical research home health services, adding new scale and capabilities to the Company’s clinical trial solutions. The total purchase consideration was $80.9 million (net of cash acquired of $1.1 million), which included payments of $9.0 million during the first quarter of 2021. The Company recognized $64.6 million of goodwill and $21.5 million of intangible assets, principally customer relationships, as a result of the acquisition. The purchase price has been allocated to the tangible assets and identifiable intangible assets acquired and liabilities assumed based upon their fair values. The excess of the purchase price over the tangible and intangible assets acquired and liabilities assumed has been recorded as goodwill. Goodwill is attributable to the acquired workforce as well as future synergies and is not deductible for income tax purposes. The operating results from the acquisition of Illingworth Research have been included in the Company’s Clinical Solutions segment from the date of acquisition. Pro forma information for these acquisitions is not presented as the operations of the acquired businesses, individually and in the aggregate, are not significant to the overall operations of the Company. Divestitures During the second quarter of 2020, the Company sold its contingent staffing business to a related party in exchange for potential future cash consideration not to exceed $4.0 million. Based on the financial results of the business one year after the divestiture date, the Company recognized $1.8 million of contingent considerati on in other (income) expense, net in the accompanying statement of income during the second quarter of 2021. Refer to “Note 16 – Related-Party Transactions” for further information. During the fourth quarter of 2020, the Company sold its medication adherence business for consideration of $23.0 million, including cash consideration of $18.0 million, net of cash transferred, and convertible notes of $5.0 million, resulting in a gain on sale of $7.1 million $3.6 million The gain on sale and contingent consideration were recognized in other (income) expense, net in the accompanying consolidated statements of income. Investments During the second quarter of 2020, the Company made a non-cash investment of $27.3 million to acquire certain intellectual property rights from a customer in lieu of cash payment for services rendered. The Company subsequently exchanged the intellectual property for an equity method investment in an unconsolidated variable interest entity. The Company provided the entity $3.8 million in cash, in the form of a loan, during the third quarter of 2021. Based on the hypothetical liquidation book value of its investment as of December 31, 2021, the Company recorded a $5.3 million loss to other (income) expense, net in the accompanying statement of income for the year ended December 31, 2021. As of December 31, 2021, the book value of the Company’s investment was $16.2 million and was included in other long-term assets in the accompanying consolidated balance sheet, with a maximum exposure to loss of approximately $20.3 million , which includes the outstanding loan balance and accrued interest

Long-Term Debt Obligations

Long-Term Debt Obligations	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Long-Term Debt Obligations	4. Long-Term Debt Obligations The Company’s debt obligations consisted of the following as of December 31 (in thousands): 2021 2020 Secured Debt Term Loan A - tranche one due March 2024 $ 149,195 $ 183,715 Term Loan A - tranche two due August 2024 1,636,797 1,273,991 Term Loan B due August 2024 — 560,564 Accounts receivable financing agreement due October 2024 400,000 300,000 Total secured debt 2,185,992 2,318,270 Unsecured Debt Senior notes due January 2029 (the “Notes”) 600,000 600,000 Total debt obligations 2,785,992 2,918,270 Less: Term loans original issuance discount (2,228 ) (3,500 ) Less: Unamortized deferred issuance costs (8,043 ) (12,716 ) Total long-term debt $ 2,775,721 $ 2,902,054 Credit Agreement The Company is party to a credit agreement (as amended, the “ ” On June 30, 2021 (the “Closing Date”), the Company entered into Amendment No. 5 (the “Fifth Amendment”) to the Credit Agreement. The Fifth Amendment modified the Credit Agreement to increase Term Loan A in an aggregate principal amount of $495.0 million (“Incremental Term Loan A”). Incremental Term Loan A was funded on the Closing Date, and the proceeds were used, along with cash on hand, to repay the outstanding Term Loan B in full under the Credit Agreement and to pay fees and expenses in connection with the Fifth Amendment and the incurrence of Incremental Term Loan A. Incremental Term Loan A has the same terms as Term Loan A under the Credit Agreement, and is subject to the same covenants. The Company recorded an additional discount of $0.5 million against the Term Loan A borrowings in connection with the Fifth Amendment, which is being amortized as a component of interest expense using the effective interest method over the term of Term Loan A. During the year ended December 31, 2021, the Company made $166.8 million and $560.5 million of voluntary prepayments against Term Loan A and Term Loan B, respectively, that were applied to future mandatory principal payments due. As a result of these and previous voluntary prepayments, the Company is not required to make a mandatory payment against the principal balance of Term Loan A until October 2023 and Term Loan B has been paid in full. In connection with these prepayments, the Company recorded a $3.6 million loss on extinguishment of debt during the year ended December 31, 2021. All obligations under the Credit Agreement are guaranteed by the Company and certain of the Company’s direct and indirect wholly-owned domestic subsidiaries. The obligations under the Credit Agreement are secured by substantially all of the assets of the Company and the guarantors, including 65% of the capital stock of certain controlled foreign subsidiaries. The term loans and the Revolver bear interest at a rate per annum equal to the Adjusted Eurocurrency Rate (“Eurocurrency Rate”) plus an applicable margin or an Alternate Base Rate plus an applicable margin. The Company may select among the Adjusted Eurocurrency Rate or the Alternate Base Rate, whichever is lower, except in circumstances where the Company requests a loan with less than a three-day notice. In such cases, the Company must use the Alternate Base Rate. The Adjusted Eurocurrency Rate is equal to the London Inter-bank Offered Rate (“LIBOR”), subject to adjustment for reserve requirements. The Alternate Base Rate is equal to the highest of: (i) the federal funds rate plus 0.50%; (ii) the Adjusted Eurocurrency Rate for an interest period of one month plus 1.00%; (iii) the rate of interest per annum quoted by The Wall Street Journal as the prime rate; and (iv) 0.00%. The applicable margins with respect to Alternate Base Rate and Adjusted Eurocurrency Rate borrowings are determined depending on the “First Lien Leverage Ratio” or the “ ” Alternate Base Rate Adjusted Eurocurrency Rate Term Loan A 0.25% - 0.50% 1.25% - 1.50% Term Loan B 0.75% - 1.00% 1.75% - 2.00% Revolver 0.25% - 0.50% 1.25% - 1.50% In February 2021, as a result of the Company’s First Lien Leverage Ratio (as defined in the Credit Agreement) being less than or equal to x, the Adjusted Eurocurrency Rate Spread (as defined in the Credit Agreement) on Term Loan A and the Revolver decreased from % to %. As of December 31, 2021, the interest rate on the Term Loan A and the Revolver was 1.35%. The Company also pays a quarterly commitment fee between 0.25% and 0.375% on the average daily unused balance of the Revolver depending on the “First Lien Leverage Ratio” at the adjustment date. Revolver and Letters of Credit The Revolver includes letters of credit ( “ ” Accounts Receivable Financing Agreement Under the Company’s accounts receivable financing agreement, certain of the Company’s consolidated subsidiaries sell accounts receivable and unbilled services (including contract assets) balances to a wholly-owned, bankruptcy-remote special purpose entity (“SPE”), which is the borrower under the facility. The facility is without recourse to the Company or any subsidiaries of the Company other than the SPE, other than with respect to limited indemnity obligations of the selling entities and the servicer of the receivables in respect of the character of the receivables sold by them and the performance of the servicing duties. On January 28, 2021, the Company amended its accounts receivable financing agreement to increase the amount it can borrow from $300.0 million to $365.0 million and drew down the additional $65.0 million to partially fund the Term Loan A and Term Loan B voluntary prepayments. Accordingly, there was no incremental impact on the Company’s total debt. On October 13, 2021, the Company further amended its accounts receivable financing agreement to increase the amount it can borrow from $ 365.0 million to $ 400.0 million, extended the maturity to October 2024, and drew down the additional $ 35.0 million. At the same time, the Company paid down $ 35.0 million on facilities under its Credit Agreement, resulting in no net impact on leverage. As of December 31, 2021, the Company had $400.0 million of outstanding borrowings under this agreement, which are recorded in long-term debt on the accompanying consolidated balance sheet. There was no remaining borrowing capacity available under this agreement as of December 31, 2021. This agreement is secured by a lien on certain receivables and other assets, and the Company has guaranteed the performance of the obligations of existing and future subsidiaries that sell and service the accounts receivable under this agreement. The available borrowing capacity varies monthly according to the levels of its eligible accounts receivable and unbilled receivables. Loans under this agreement will accrue interest at a reserve-adjusted LIBOR rate or a base rate equal to the higher of (i) the applicable lender’s prime rate and (ii) the federal funds rate plus 0.50%. As of December 31, 2021, the interest rate on the accounts receivable financing agreement was 1.05%. The Notes On November 24, 2020, the Company completed the issuance and sale of the Notes, with an aggregate principal amount of $600.0 million, which bears interest at a rate of 3.625% per annum, payable semi-annually in arrears beginning on July 15, 2021, and matures on January 15, 2029. The Company may redeem some or all of the Notes at any time prior to January 15, 2024 at a redemption price equal to 100% of the aggregate principal amount of the Notes to be redeemed plus a “make-whole” premium and accrued and unpaid interest. In addition, prior to July 15, 2023, the Company may redeem up to 40% of the original principal amount of the Notes with proceeds of certain equity offerings at a redemption price equal to 103.625% of the aggregate principal amount of such Notes plus accrued and unpaid interest. On or after January 15, 2024, the Company may redeem some or all of the Notes at the redemption prices set forth in the Indenture plus accrued and unpaid interest. If the Company sells certain of its assets or experience specific kinds of changes of control, the Company is required to offer to repurchase the Notes at a repurchase price equal to (1) par plus any accrued and unpaid interest in the case of an asset sale or (2) 101% of the aggregate principal amount thereof plus any accrued and unpaid interest in the case of a change of control. Maturities of Debt Obligations As of December 31, 2021, the contractual maturities of the Company’s debt obligations (excluding finance leases that are presented in “ ” 2022 $ — 2023 21,732 2024 2,164,260 2025 — 2026 — 2027 and thereafter 600,000 Less: Term loan original issuance discount (2,228 ) Less: Unamortized deferred issuance costs (8,043 ) Total $ 2,775,721

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	5. Leases The Company’s operating leases are primarily related to its office facilities. The Company’s finance leases are related to vehicles that the Company leases for certain sales representatives in its Commercial Solutions segment. The Company’s leases have remaining lease terms of less than one year to 11 years, some of which include options to extend the term or terminate the lease. ROU assets and lease liabilities are recognized based on the present value of the fixed lease payments over the lease term at the commencement date. The ROU assets also include any initial direct costs incurred and lease payments made at or before the commencement date, and are reduced by lease incentives. The Company uses its incremental borrowing rate as the discount rate to determine the present value of the lease payments for leases that do not have a readily determinable implicit discount rate. The Company’s incremental borrowing rate is the rate of interest that it would have to borrow on a collateralized basis over a similar term and amount in a similar economic environment. The Company determines the incremental borrowing rates for its leases by adjusting the local risk free interest rate with a credit risk premium corresponding to the Company’s credit rating. The Company records rent expense for its operating leases on a straight-line basis from the lease commencement date until the end of the lease term. The Company records finance lease cost as a combination of the amortization expense for the ROU assets and interest expense for the outstanding lease liabilities using the discount rate discussed above. Variable lease payments for operating leases are related to office facilities and include but are not limited to common area maintenance, parking, electricity, and management fees. The variable lease payments for finance leases are related to maintenance programs for leased vehicles. Variable lease payments are based on occurrence or based on usage; therefore, they are not included as part of the initial calculations of the ROU assets and liabilities. The components of lease cost were as follows for the year ended December 31 and the line items on the accompanying consolidated statements of income to which they were recorded were as follows (in thousands): Statement of Income Classification 2021 2020 Operating leases: Fixed lease costs Direct costs, selling, general, and administrative expenses and restructuring and other costs $ 55,168 $ 53,531 Short-term lease costs Direct costs and selling, general, and administrative expenses 1,994 2,930 Variable lease costs Direct costs, selling, general, and administrative expenses and restructuring and other costs 36,760 29,572 Total operating lease costs $ 93,922 $ 86,033 Finance leases: Amortization of right-of-use assets Depreciation $ 17,453 $ 15,843 Interest on lease liabilities Interest expense 605 944 Variable lease costs Direct costs 6,231 6,321 Total finance lease costs $ 24,289 $ 23,108 Supplemental balance sheet information related to finance leases was as follows as of December 31 (in thousands): 2021 2020 Property and equipment, gross $ 77,674 $ 63,985 Accumulated depreciation (30,021 ) (20,479 ) Property and equipment, net $ 47,653 $ 43,506 Current portion of finance lease obligations $ 20,627 $ 17,455 Finance lease long-term obligations 34,181 31,522 Total finance lease liabilities $ 54,808 $ 48,977 Supplemental cash flow information related to leases was as follows for the year ended December 31 (in thousands): 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ (59,863 ) $ (60,361 ) Operating cash flows for finance leases (605 ) (944 ) Financing cash flows for finance leases (15,774 ) (16,434 ) Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 43,385 $ 47,415 Finance leases 28,994 20,203 Lease obligations closed out in exchange for right-of-use assets: Operating leases $ (10,122 ) $ (2,834 ) Weighted average remaining lease term as of December 31: 2021 2020 Operating leases 6 years 7 years Finance leases 3 years 3 years Weighted average discount rate as of December 31: 2021 2020 Operating leases 4.7 % 4.8 % Finance leases 1.1 % 1.3 % As of December 31, 2021, maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Total 2022 $ 53,612 $ 21,443 $ 75,055 2023 53,033 17,768 70,801 2024 44,428 11,624 56,052 2025 38,036 5,688 43,724 2026 29,128 130 29,258 2027 and thereafter 73,262 — 73,262 Total lease payments 291,499 56,653 $ 348,152 Less: Management fee — (762 ) Less: Imputed interest (42,643 ) (1,083 ) Total lease liabilities $ 248,856 $ 54,808

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2021
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivatives	6. Derivatives Interest Rate Swaps The Company has entered into various interest rate swaps to mitigate its exposure to changes in interest rates on its term loan. In June 2018, the Company entered into an interest rate swap with multiple counterparties that had an initial aggregate notional value of $1.01 billion, an effective date of December 31, 2018, and expired on June 30, 2021. In March 2020, the Company entered into interest rate swaps with multiple counterparties. The interest rate swaps had an initial aggregate notional value of $549.2 million that increased to $1.42 billion on June 30, 2021, an effective date of March 31, 2020, and will expire on March 31, 2023. As of December 31, 2021, the notional value of this interest rate swap was $1.16 billion. The significant terms of these derivatives are substantially the same as those contained within the Credit Agreement, including monthly settlements with the swap counterparties. Interest rate swaps are designated as hedging instruments. The amounts of hedge ineffectiveness recorded in net income during the years ended December 31, 2021, 2020, and 2019 were insignificant. Foreign Exchange Forward On October 30, 2020, the Company entered into a foreign exchange forward in order to minimize monthly foreign currency remeasurement gains or losses on non-functional currency monetary balances. The foreign exchange forward notional value may be adjusted each month as the exposure balance changes. The Company did not designate the derivative as a hedge. All changes in the fair value of the foreign exchange forward are recorded in earnings every month to other (income) expense, net in the accompanying consolidated statements of income. The Company recognized $0.7 million of realized losses and $1.5 million of realized gains during the years ended December 31, 2021 and 2020, respectively, related to this foreign exchange forward. As of December 31, 2021, the notional value of this foreign exchange forward was $70.0 million. Fair Values The fair values of the Company’s derivative financial instruments as of December 31 and the line items on the accompanying consolidated balance sheets to which they were recorded were as follows (in thousands): Balance Sheet Classification 2021 2020 Interest rate swaps - non-current Other long-term assets $ 948 $ — Fair value of derivative assets $ 948 $ — Interest rate swaps - current Accrued expenses $ 1,827 $ 17,045 Interest rate swaps - non-current Other long-term liabilities — 5,572 Fair value of derivative liabilities $ 1,827 $ 22,617

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	7. Fair Value Measurements Assets and Liabilities Carried at Fair Value As of December 31, 2021 and 2020, the Company’s financial assets and liabilities carried at fair value included cash and cash equivalents, restricted cash, trading securities, accounts receivable, unbilled services (including contract assets), accounts payable, accrued expenses, deferred revenue, contingent obligations, liabilities under the accounts receivable financing agreement, and derivative instruments. The fair values of cash and cash equivalents, restricted cash, accounts receivable, unbilled services (including contract assets), accounts payable, accrued expenses, deferred revenue, and the liabilities under the accounts receivable financing agreement approximate their respective carrying amounts because of the liquidity and short-term nature of these financial instruments. Financial Instruments Subject to Recurring Fair Value Measurements As of December 31, 2021, the fair values of the major classes of the Company’s assets and liabilities measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 Investments Measured at Net Asset Value Total Assets: Trading securities (a) $ 24,775 $ — $ — $ — $ 24,775 Partnership interest (b) — — — 11,176 11,176 Derivative instruments (c) — 948 — — 948 Total assets $ 24,775 $ 948 $ — $ 11,176 $ 36,899 Liabilities: Derivative instruments (c) $ — $ 1,827 $ — $ — $ 1,827 Contingent obligations related to acquisitions (d) — — 17,997 — 17,997 Total liabilities $ — $ 1,827 $ 17,997 $ — $ 19,824 As of December 31, 2020, the fair value of the major classes of the Company’s assets and liabilities measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 Investments Measured at Net Asset Value Total Assets: Trading securities (a) $ 22,950 $ — $ — $ — $ 22,950 Partnership interest (b) — — — 8,665 8,665 Total assets $ 22,950 $ — $ — $ 8,665 $ 31,615 Liabilities: Derivative instruments (c) $ — $ 22,617 $ — $ — $ 22,617 Contingent obligations related to acquisitions (d) — — 6,793 — 6,793 Total liabilities $ — $ 22,617 $ 6,793 $ — $ 29,410 (a) Represents the fair value of investments in mutual funds based on quoted market prices that are used to fund the liability associated with the Company’s deferred compensation plan. (b) The Company has committed to invest $21.5 million as a limited partner in two private equity funds. The private equity funds invest in opportunities in the healthcare and life sciences industry. As of December 31, 2021, the Company’s remaining unfunded commitment in the private equity funds was $12.8 million. The Company holds minor ownership interests (less than 3%) in each of the private equity funds and has determined that it does not exercise significant influence over the private equity funds’ operating or finance activities. As the private equity funds do not have readily determinable fair values, the Company has estimated the fair values using each fund’s Net Asset Value, the amount by which the value of all assets exceeds all debt and liabilities, in accordance with ASC Topic 946 , Financial Services – Investment Companies. (c) Represents the fair value of interest rate swap arrangements (see “ – ” (d) Represents the fair value of contingent consideration obligations related to acquisitions. The fair values of these liabilities are determined based on the Company’s best estimate of the probable timing and amount of settlement. The following table presents a reconciliation of changes in the carrying amount of contingent obligations classified as Level 3 for the years ended December 31, 2021 and 2020 (in thousands): Balance as of December 31, 2019 $ 37,324 Additions — Changes in fair value recognized in earnings (a) (3,897 ) Payments (26,634 ) Balance as of December 31, 2020 6,793 Additions (b) 19,158 Changes in fair value recognized in earnings (757 ) Payments (c) (7,197 ) Balance as of December 31, 2021 $ 17,997 (a) The change in fair value recognized in earnings for the year ended December 31, 2020 is primarily due to a decrease in the estimate of the contingent consideration associated with the acquisition of Kinapse (see “ ” (b) Represents obligations in connection with the acquisition of RxDataScience and insignificant acquisitions completed during 2021. ( c ) The Company made payments to fully settle the contingent tax-sharing obligation arising from inVentiv Health, Inc.’s 2016 merger with Double Eagle Parent, Inc. (see “Note 1 7 – Commitments and Contingencies” for further information) during the first quarter of 2021 and obligations in connection with the insignificant acquisition completed during the second quarter of 2021 . During the years ended December 31, 2021 and 2020, there were no transfers of assets or liabilities between Level 1, Level 2, or Level 3 fair value measurements. Financial Instruments Subject to Non-Recurring Fair Value Measurements Certain assets, including goodwill and identifiable intangible assets, are carried on the accompanying consolidated balance sheets at cost and, subsequent to initial recognition, are measured at fair value on a non-recurring basis when certain identified events or changes in circumstances that may have a significant adverse effect on the carrying values of these assets occur. These assets are classified as Level 3 fair value measurements within the fair value hierarchy. Goodwill is tested for impairment annually or more frequently if events or changes in circumstances indicate a triggering event has occurred. Intangible assets are tested for impairment upon the occurrence of certain triggering events. As of December 31, 2021 and 2020, assets carried on the consolidated balance sheets and not remeasured to fair value on a recurring basis totaled $5.83 billion and $5.71 billion, respectively. Fair Value Disclosures for Financial Instruments Not Carried at Fair Value The estimated fair values of the term loans and the Notes are determined based on the price that the Company would have had to pay to settle the liabilities. As these liabilities are not actively traded, they are classified as Level 2 fair value measurements. The estimated fair values of the Company’s term loans and the Notes were as follows (in thousands): December 31, 2021 December 31, 2020 Carrying Value (a) Estimated Fair Value Carrying Value (a) Estimated Fair Value Term Loan A - tranche one due March 2024 $ 149,008 $ 148,945 $ 183,320 $ 183,026 Term Loan A - tranche two due August 2024 1,634,756 1,635,138 1,271,255 1,269,213 Term Loan B due August 2024 — — 560,194 560,144 Senior notes due January 2029 600,000 595,500 600,000 602,412 (a) The carrying value of the term loan debt is shown net of original issue discounts.

Restructuring and Other Costs

Restructuring and Other Costs	12 Months Ended
	Dec. 31, 2021
Restructuring And Related Activities [Abstract]
Restructuring and Other Costs	8. Restructuring and Other Costs During the year ended December 31, 2021, the Company incurred employee severance and benefit costs, facility and lease termination costs, and other costs related to its restructuring activities. These costs were primarily related to the Company’s ForwardBound margin enhancement initiative. The costs incurred during the year ended December 31, 2020 were primarily related to the Company’s cost management strategies in response to the COVID-19 pandemic as well as the Company’s ForwardBound initiative. Restructuring and other costs consisted of the following (in thousands): Year Ended December 31, 2021 2020 2019 Employee severance and benefit costs $ 14,526 $ 26,321 $ 25,243 Facility and lease termination costs 8,226 2,313 16,202 Other costs 64 780 690 Total restructuring and other costs $ 22,816 $ 29,414 $ 42,135 The Company expects to continue to incur costs related to restructuring of its operations in order to achieve cost savings and the targeted synergies related to its acquisitions. However, the timing and the amount of these costs depends on various factors, including, but not limited to, identifying and realizing synergy opportunities and executing the integration of its combined operations. The Company may also continue to incur additional restructuring and other costs during and beyond 2022 related to its ForwardBound Accrued Restructuring Liabilities The following table summarizes activity related to the liabilities associated with restructuring and other costs (in thousands): Employee Severance Costs Other Costs Total Balance as of December 31, 2019 $ 5,728 $ 22 $ 5,750 Expenses incurred (a) 26,321 791 27,112 Payments (26,219 ) (813 ) (27,032 ) Balance as of December 31, 2020 5,830 — 5,830 Expenses incurred (a) 14,574 17 14,591 Payments (13,747 ) (17 ) (13,764 ) Balance as of December 31, 2021 $ 6,657 $ — $ 6,657 (a) There were no non-cash restructuring and other expenses incurred for the years ended December 31, 2021 and 2020. The amount of expenses incurred for the years ended December 31, 2021 and 2020 excludes $8.2 million and $2.3 million, respectively, of facility lease closure and lease termination costs that are reflected as a reduction of operating lease right-of-use assets on the accompanying consolidated balance sheets under ASC 842. The Company expects the employee severance costs accrued as of December 31, 2021 will be paid within the next twelve months. Liabilities associated with restructuring and other costs are included in accrued expenses and other long-term liabilities on the accompanying consolidated balance sheets.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Shareholders' Equity	9. Shareholders’ Equity Shares Outstanding Shares of common stock outstanding were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Common stock shares, beginning balance 103,935 103,866 103,372 Repurchases of common stock (1,500 ) (1,256 ) (1,323 ) Issuances of common stock 1,329 1,325 1,817 Common stock shares, ending balance 103,764 103,935 103,866 Stock Repurchase Programs On February 26, 2018, the Company’s Board of Directors (the “ ” “2018 St ” On November 17, 2020, the Company’s Board authorized the repurchase of up to an aggregate of $300.0 million of the Company’s Class A common stock, par value $0.01 per share, to be executed from time to time in open market transactions effected through a broker at prevailing market prices, in block trades, or through privately negotiated transactions through December 31, 2022 (the “2021 Stock Repurchase Program”). The 2021 Stock Repurchase Program took effect on January 1, 2021. The 2021 Stock Repurchase Program does not obligate the Company to repurchase any particular amount of the Company’s common stock, and may be modified, extended, suspended, or discontinued at any time. The timing and amount of repurchases are determined by the Company’s management based on a variety of factors such as the market price of the Company’s common stock, the Company’s corporate cash requirements, and overall market conditions. The 2021 Stock Repurchase Program is subject to applicable legal requirements, including federal and state securities laws and applicable Nasdaq rules. The Company may also repurchase shares of its common stock pursuant to a trading plan meeting the requirements of Rule 10b5-1 under the Securities Exchange Act of 1934, as amended, which would permit shares of the Company’s common stock to be repurchased when the Company might otherwise be precluded from doing so by law. During the year ended December 31, 2021, the Company repurchased 1,500,000 of its common stock in private transactions under the 2021 Stock Repurchase Program, for a total purchase price of approximately $117.5 million. The following table sets forth repurchase activity under the Company’s stock repurchase programs from inception through December 31, 2021: Total number of shares purchased Average price paid per share Approximate dollar value of shares purchased (in thousands) March 2018 948,100 $ 39.55 $ 37,493 April 2018 1,024,400 36.60 37,492 January 2019 552,100 39.16 21,623 February 2019 120,600 41.40 4,993 June 2019 509,100 45.29 23,055 August 2019 141,100 49.93 7,045 March 2020 600,000 53.38 32,029 September 2020 506,244 59.26 30,000 October 2020 150,000 54.14 8,122 March 2021 600,000 74.18 44,505 May 2021 400,000 81.04 32,416 June 2021 500,000 81.20 40,600 Total 6,051,644 $ 319,373 The Company immediately retired all of the repurchased common stock and charged the par value of the shares to common stock. The excess of the repurchase price over the par value was applied on a pro rata basis against additional paid-in capital, with the remainder applied to accumulated deficit. As of December 31, 2021, the Company had remaining authorization to repurchase up to approximately $182.5 million of shares of its common stock under the 2021 Stock Repurchase Program. The following is a summary of the Company’s authorized, issued, and outstanding shares as of December 31: 2021 2020 Shares Authorized: Class A common stock 300,000,000 300,000,000 Class B common stock 300,000,000 300,000,000 Preferred stock 30,000,000 30,000,000 Total shares authorized 630,000,000 630,000,000 Shares Issued and Outstanding: Class A common stock 103,763,635 103,934,738 Class B common stock — — Preferred stock — — Total shares issued and outstanding 103,763,635 103,934,738 Voting Rights and Conversion Rights of Common Stock Each share of Class A common stock is entitled to one vote on all matters to be voted on by the shareholders of the Company, including the election of directors. Each share of Class B common stock is entitled to one vote on all matters to be voted on by the shareholders of the Company, except for the right to vote in the election of directors. Additionally, each share of Class B common stock is convertible (on a one-for-one basis) into Class A common stock at any time at the election of the holder. Dividend Rights and Preferences of Common Stock The holders of Class A and Class B common stock are entitled to dividends on a pro rata basis at such time and in such amounts as declared by the Board. There were no dividends paid during the years ended December 31, 2021, 2020, or 2019. Liquidation Rights and Preferences of Common Stock The holders of Class A and Class B common stock are entitled to participate on a pro rata basis in all distributions made in connection with a voluntary or involuntary liquidation, dissolution, or winding up of the affairs of the Company.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share	10. Earnings Per Share The following table provides a reconciliation of the numerators and denominators of the basic and diluted earnings per share computations (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Numerator: Net income $ 234,831 $ 192,787 $ 131,258 Denominator: Basic weighted average common shares outstanding 103,872 104,168 103,618 Effect of dilutive securities: Stock options and other awards under deferred share-based compensation programs 1,193 1,297 1,387 Diluted weighted average common shares outstanding 105,065 105,465 105,005 Earnings per share: Basic $ 2.26 $ 1.85 $ 1.27 Diluted $ 2.24 $ 1.83 $ 1.25 Potential common shares outstanding that are considered anti-dilutive are excluded from the computation of diluted earnings per share. Potential common shares related to stock options and other awards under share-based compensation programs may be determined to be anti-dilutive based on the application of the treasury stock method. Potential common shares are also anti-dilutive in periods when the Company incurs a net loss. The number of potential shares outstanding that were anti-dilutive and therefore excluded from the computation of diluted earnings per share, weighted for the portion of the period they were outstanding, were 145,342, 582,760, and 277,128 for the years ended December 31, 2021, 2020, and 2019, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income Taxes	11. Income Taxes The components of income before provision for income taxes were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Domestic $ 186,445 $ 122,659 $ (17,066 ) Foreign 128,715 80,999 118,775 Income before provision for income taxes $ 315,160 $ 203,658 $ 101,709 The components of income tax expense (benefit) were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Federal income taxes: Current $ 926 $ (15,537 ) $ (13,952 ) Deferred 45,819 10,188 (11,693 ) Foreign income taxes: Current 27,718 16,019 21,452 Deferred (4,309 ) (3,106 ) (2,206 ) State income taxes: Current 5,163 14,229 2,850 Deferred 5,012 (10,922 ) (26,000 ) Income tax expense (benefit) $ 80,329 $ 10,871 $ (29,549 ) Foreign Earnings The Company ha s approximately $ 689.7 million of undistributed foreign earnings, of which approximately $ 278.4 million will remain indefinitely reinvested in the foreign jurisdictions. These earnings are expected to be used to support the growth and working capital needs of the Company’s foreign subsidiaries. It is impracticable to determine the total amount of unrecognized deferred taxes with respect to these indefinitely reinvested earnings. The remaining $ 411.3 million of undistributed foreign earnings are not considered indefinitely reinvested, and the Company has provided a $ 7.8 million deferred t ax liability, primarily related to the estimated withholding tax and state taxes that would be due upon repatriation. BEAT The Company ’ g payments do not exceed the base erosion and anti-abuse minimum tax (“BEAT”) Actual income tax expense differed from the amount computed by applying the U.S. federal tax rate of 21% to pre-tax income as a result of the following (in thousands): Year Ended December 31, 2021 2020 2019 Expected income tax expense at statutory rate $ 66,184 $ 42,768 $ 21,359 Change in income tax expense resulting from: Foreign income inclusion 11,019 6,013 39,557 Foreign earnings not indefinitely reinvested 278 5,071 — Foreign tax credits (4,390 ) — — Changes in income tax valuation allowance (all jurisdictions) (1,462 ) 14,503 (68,537 ) Change in fair value of contingent obligations (122 ) (769 ) 3,625 Share-based compensation (5,662 ) (2,800 ) 1,094 Research and general business tax credits (a) (8,902 ) (12,872 ) (1,871 ) State and local taxes, net of federal benefit 11,978 6,924 (9,085 ) Capital loss carryforward (b) (214 ) (16,506 ) — Foreign rate differential 2,865 (1,777 ) (3,595 ) Changes in reserve for uncertain tax positions including interest 4,721 (18,839 ) 5,393 Provision to tax return and other deferred tax adjustments (771 ) (12,325 ) (6,950 ) Gain on sale of business — (2,350 ) — Base erosion and anti-abuse tax — — (15,054 ) Nondeductible executive compensation 1,649 367 1,802 Other, net 3,158 3,463 2,713 Income tax expense (benefit) $ 80,329 $ 10,871 $ (29,549 ) (a) Year ended December 31, 2021 included a $0.8 million valuation allowance release and year ended December 31, 2020 was offset by a $9.4 million valuation allowance. (b) Years ended December 31, 2021 and 2020 are offset by $0.2 million and $16.5 million, respectively, in valuation allowances. The changes in the valuation allowance for deferred tax assets were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Balance at the beginning of the period $ 100,310 $ 84,159 $ 150,316 Deferred tax assets assumed through acquisitions — 479 — Deferred tax assets released through divestitures — (271 ) — (Credited) charged to income tax expense (1,462 ) 14,503 (68,537 ) Charged to equity — — 42 Foreign currency exchange (407 ) 1,440 2,338 Other adjustments (479 ) — — Balance at the end of the period $ 97,962 $ 100,310 $ 84,159 As of December 31, 2021, the valuation allowance decreased by $2.3 million, resulting primarily from a net decrease of $1.5 million primarily due to releasing a domestic valuation allowance related to state deferred tax assets. As of December 31, 2020, the valuation allowance increased by $16.2 million, resulting from a net increase of $14.5 million primarily due to recording a federal U.S. valuation allowance related to capital loss carryforwards as well as recording a valuation allowance related to foreign research and development credits, partially offset by the release of a valuation allowance on U.S. state deferred tax assets and an increase of $1.4 million for changes related to foreign currency exchange. The income tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities are as follows as of December 31 (in thousands): 2021 2020 Deferred tax assets: Net operating losses $ 134,143 $ 122,018 Tax credits 58,901 58,603 Deferred revenue — 77,138 Employee compensation and other benefits 28,538 29,048 Allowance for doubtful accounts 1,787 1,739 Lease obligations 57,749 57,142 Accrued expenses 13,158 6,526 Prepaid royalty — 3,451 Capital loss carryforward 20,021 20,157 Interest limitation carryforwards 30,847 20,219 Other 1,151 7,913 Total deferred tax assets 346,295 403,954 Less: valuation allowance (97,962 ) (100,310 ) Net deferred tax assets 248,333 303,644 Deferred tax liabilities: Undistributed foreign earnings (7,778 ) (10,912 ) Right of use asset (47,532 ) (49,316 ) Depreciation and amortization (214,636 ) (226,170 ) Deferred revenue (17,247 ) — Other (3,814 ) (2,404 ) Total deferred tax liabilities (291,007 ) (288,802 ) Net deferred tax assets $ (42,674 ) $ 14,842 As of December 31, 2021 and 2020, the Company had U.S. federal net operating loss (“NOL”) carryforwards of approximately $317.4 million and $260.6 million, respectively. These carryforwards begin to expire in 2029, but the Company anticipates utilizing such carryforwards prior to their expirations. As of December 31, 2021 and 2020, the Company had state NOL carryforwards of approximately $840.4 million and $821.0 million, respectively, a portion of which expire annually. The Company also had foreign NOL carryforwards of $98.9 million and $80.1 million as of December 31, 2021 and 2020, respectively. The majority of these carryforwards have indefinite carryforward periods, but valuation allowances have been established for jurisdictions where the future benefits of the NOL carryforwards are not more likely than not to be realized. As of December 31, 2021 and 2020, the Company had Canadian research and development credit carryforwards of $56.1 million and $56.7 million, respectively. These credit carryforwards have an indefinite life, but for the years ended December 31, 2021 and 2020, valuation allowances of $56.1 million and $56.7 million, respectively, have been established against these tax credits where the future benefits of the credits are not more likely than not to be realized. The Company’s gross unrecognized tax benefits, exclusive of associated interest and penalties, were $12.1 million and $9.0 million as of December 31, 2021 and 2020, respectively. The increase of $3.1 million was primarily due to increase in positions relating to prior years in foreign jurisdictions partially offset with the settlement of unrecognized tax benefits in the U.S. The Company recognizes accrued interest and penalties related to uncertain tax positions in income tax expense in the accompanying consolidated statements of income. As of December 31, 2021 and 2020, the Company had accrued interest and penalties related to uncertain tax positions of $2.4 million and $2.8 million, respectively. The Company believes it is reasonably possible that its unrecognized tax benefits may decrease by approximately $1.6 million within the next 12 months as a result of lapses in statutes of limitations. A reconciliation of the beginning and ending balances of unrecognized tax benefits, excluding accrued interest and penalties, is as follows (in thousands): Unrecognized tax benefits balance as of December 31, 2018 $ 19,245 Increases for tax positions in the current year 2,222 Increases for tax positions of prior years 2,255 Decreases for tax positions in prior year (440 ) Impact of foreign currency translation (44 ) Unrecognized tax benefits balance as of December 31, 2019 23,238 Increases for tax positions in the current year 254 Increases for tax positions of prior years 3,237 Decreases for tax positions in prior year (2,540 ) Impact of foreign currency translation 132 Lapse of statute limitations (15,288 ) Unrecognized tax benefits balance as of December 31, 2020 9,033 Increases for tax positions in the current year 386 Increases for tax positions of prior years 4,233 Settlements with tax authorities (1,131 ) Impact of foreign currency translation (169 ) Lapse of statute limitations (234 ) Unrecognized tax benefits balance as of December 31, 2021 $ 12,118 Due to the geographic breadth of the Company’s operations, numerous tax audits may be ongoing throughout the world at any point in time. Income tax liabilities are recorded based on estimates of additional income taxes which will be due upon the conclusion of these audits. Estimates of these income tax liabilities are made based upon prior experience and are updated in light of changes in facts and circumstances. However, due to the uncertain and complex application of tax regulations, it is possible that the ultimate resolution of audits may result in liabilities which could be materially different from these estimates. In such an event, the Company will record additional income tax expense or benefit in the period in which such resolution occurs. The Company is not currently under any U.S. federal income tax audits, however, income tax returns are under examination by tax authorities in several state and foreign jurisdictions. The Company’s federal and state tax filings are open to investigations in numerous years due to NOL carryforwards. Additionally, the Company currently has an ongoing examination for tax years 2017 to 2019 in the United Kingdom. The United Kingdom is the jurisdiction with the Company’s largest foreign operations. The Company believes that its reserve for uncertain tax positions is adequate to cover existing risks or exposures related to all open tax years and jurisdictions.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2021
Revenue From Contract With Customer [Abstract]
Revenue from Contract with Customers	12. Revenue from Contracts with Customers Unsatisfied Performance Obligations As of December 31, 2021, the total aggregate transaction price allocated to the unsatisfied performance obligations under contracts with contract terms greater than one year and that are not accounted for as a series pursuant to ASC 606 was $6.70 billion. This amount includes revenue associated with reimbursable out-of-pocket expenses. The Company expects to recognize revenue over the remaining contract term of the individual projects, with contract terms generally ranging from one to five years. The amount of unsatisfied performance obligations is presented net of any constraints and, as a result, is lower than the potential contractual revenue. The contracts excluded due to constraints include contracts that do not commence within a certain period of time or that require the Company to undertake numerous activities to fulfill these performance obligations, including various activities that are outside of the Company’s control. Timing of Billing and Performance During the year ended December 31, 2021, the Company recognized approximately $611.9 million of revenue that was included in the deferred revenue balance at the beginning of the year. During the year ended December 31, 2021, approximately $120.9 million of the Company’s revenue recognized was allocated to performance obligations partially satisfied in previous periods, substantially all of which was associated with changes in scope or price for full-service clinical studies. The Company reviews its portfolio level risk and inflation factors during the third quarter of each year. Based on this review, the Company modified the application of its portfolio level inflation factor, which was considered a change in estimate, and recognized additional revenue of $23.5 million related to this change during the third quarter of 2021. As a result of changing service delivery trends in connection with the COVID-19 pandemic and adoption of decentralized trial methodologies, the Company implemented a comprehensive approach during the fourth quarter of 2021 related to anticipated reductions in reimbursable out-of-pocket expenses, which was considered a change in estimate, and recognized additional net revenue of $44.0 million during the period. This amount related to anticipated changes in reimbursable out-of-pocket expenses, inclusive of both the revised approach as well as updates to project estimates made in the normal course of business. The additional revenue related to these changes in estimates was partially offset by insignificant changes in estimates related to projects recognized in the normal course of the Company’s revenue recognition processes

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Segment Information	13. Segment Information The Company is managed through two reportable segments: Clinical Solutions and Commercial Solutions. Each reportable segment consists of multiple service offerings that, when combined, create a fully integrated . The segment is organized around clinical pharmacology and bioanalytical services, workforce deployment, full-service clinical studies, real world evidence, and consulting. This segment offers individual services including product development and regulatory consulting, project management, protocol development, investigational site recruitment, clinical monitoring, technology-enabled patient recruitment and engagement, clinical home health services, clinical trial diversity, biometrics, and regulatory affairs; all across a comprehensive range of therapeutic areas. Commercial Solutions provides the pharmaceutical, biotechnology, and healthcare industries with commercialization services, including deployment solutions, communications solutions (public relations, advertising, and medical communications), and consulting services. The Company’s Chief Operating Decision Maker (the “ ” Prior period segment results have been recast to reflect the transfer of the Kinapse Regulatory and Operations Consulting service lines from Commercial Solutions to Clinical Solutions to align with management reporting in 2021. Information about reportable segment operating results was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Revenue: Clinical Solutions $ 4,009,057 $ 3,339,451 $ 3,450,223 Commercial Solutions 1,203,913 1,076,326 1,225,592 Total revenue 5,212,970 4,415,777 4,675,815 Segment direct costs: Clinical Solutions 3,005,938 2,513,240 2,637,016 Commercial Solutions 955,326 853,555 979,878 Total segment direct costs 3,961,264 3,366,795 3,616,894 Segment selling, general, and administrative expenses: Clinical Solutions 353,990 283,633 280,674 Commercial Solutions 82,516 82,709 87,258 Total segment selling, general, and administrative expenses 436,506 366,342 367,932 Segment operating income: Clinical Solutions 649,129 542,578 532,533 Commercial Solutions 166,071 140,062 158,456 Total segment operating income 815,200 682,640 690,989 Direct costs and operating expenses not allocated to segments: Share-based compensation included in direct costs 33,220 31,347 29,011 Share-based compensation included in selling, general, and administrative expenses 31,984 27,144 26,182 Corporate selling, general, and administrative expenses 102,275 79,240 113,442 Restructuring and other costs 22,816 29,414 42,135 Depreciation and amortization 235,625 222,352 242,465 Total income from operations $ 389,280 $ 293,143 $ 237,754

Operations by Geographic Locati

Operations by Geographic Location	12 Months Ended
	Dec. 31, 2021
Segments Geographical Areas [Abstract]
Operations by Geographic Location	14. Operations by Geographic Location The following table summarizes total revenue by geographic area (in thousands, all intercompany transactions have been eliminated): Year Ended December 31, 2021 2020 2019 Revenue: North America (a) $ 3,144,475 $ 2,791,590 $ 3,079,608 Europe, Middle East and Africa 1,333,540 1,059,968 1,055,007 Asia-Pacific 594,163 465,116 444,819 Latin America 140,792 99,103 96,381 Total revenue $ 5,212,970 $ 4,415,777 $ 4,675,815 (a) Revenue for the North America region includes revenue attributable to the U.S. of $2.95 billion, $2.64 billion, and $2.93 billion, or 56.6%, 59.9%, and 62.7% of total revenue, for the years ended December 31, 2021, 2020 and 2019, respectively. No other country represented more than 10% of total revenue for any year. The following table summarizes long-lived assets by geographic area as of December 31 (in thousands, all intercompany transactions have been eliminated): 2021 2020 Property and equipment, net: North America (a) $ 165,446 $ 161,531 Europe, Middle East and Africa 37,004 38,745 Asia-Pacific 13,615 11,167 Latin America 6,592 4,757 Total property and equipment, net $ 222,657 $ 216,200 (a) Long-lived assets for the North America region include property and equipment, net attributable to the U.S. of $160.0 million and $156.0 million as of December 31, 2021 and 2020, respectively.

Concentration of Credit Risk

Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2021
Risks And Uncertainties [Abstract]
Concentration of Credit Risk	15. Concentration of Credit Risk Financial assets that subject the Company to credit risk primarily consist of cash and cash equivalents, accounts receivable and unbilled services (including contract assets). The Company’s cash and cash equivalents consist principally of cash and are maintained at several financial institutions with reputable credit ratings. The Company maintains cash depository accounts with several financial institutions worldwide and is exposed to credit risk related to the potential inability to access liquidity in financial institutions where its cash and cash equivalents are concentrated. The Company has not historically incurred any losses with respect to these balances and believes that they bear minimal credit risk. As of December 31, 2021 and 2020, substantially all of the Company’s cash and cash equivalents were held within the U.S. Substantially all of the Company’s revenue is earned by performing services under contracts with pharmaceutical and biotechnology companies. The concentration of credit risk is equal to the outstanding accounts receivable and unbilled services (including contract assets) balances less deferred revenue. No single customer accounted for greater than 10% of the Company’s revenue for the years ended December 31, 2021, 2020 or 2019. No single customer accounted for greater than 10% of the Company’s accounts receivable and unbilled services (including contract assets) balances for the year ended December 31, 2021 or 2020.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2021
Related Party Transactions [Abstract]
Related-Party Transactions	16. Related-Party Transactions For the year ended December 31, 2021, the Company had combined revenue of $3.7 million from three customers whose board of directors each included a member who was also a member of the Company’s Board. The combined revenue reflects the periods in which the member served on both the customer’s board of directors and the Company’s Board. As of December 31, 2021, the Company had combined receivables of $0.6 million from On October 6, 2021, the Company completed the acquisition of RxDataScience through an arm’s-length transaction. A member of the Company’s management was the co-founder and minority shareholder of RxDataScience and continued to be an executive advisor at RxDataScience up until the acquisition date. For additional information, refer to “Note 3 – Acquisitions, Divestitures, and Investments” and “Note 7 – Fair Value Measurements.” For the year ended December 31, 2020, the Company had revenue of $1.8 million and, as of December 31, 2020, receivables of $1.3 million from a customer whose board of directors included a member who was also a member of the Company’s Board. This customer became a related party during the third quarter of 2020. During the second quarter of 2020, the Company sold its contingent staffing business to a related party in exchange for potential future cash consideration not to exceed $4.0 million. The acquiring company had a significant shareholder who was also a significant shareholder of the Company. The significant shareholder sold their interest in the acquiring company during March 2021. Based on the financial results of the business one year after the divestiture date, the Company recognized $1.8 million of contingent consideration in other (income) expense, net i n the second quarter of 2021. The future cash consideration is contingent on the financial performance of the sold business through May 31, 2023. The Company will recognize the contingent consideration in the consolidated statements of income in the period the contingency is resolved. For the year ended December 31, 2019, the Company had revenue of $0.4 million from a customer whose board of directors included a member who was also a member of the Company’s Board. This customer became a related party of the Company during the fourth quarter of 2019. For the year ended December 31, 2018, the Company had revenue of $0.4 million from two customers each of whose respective boards of directors included a member who was also a member of the Company’s Board For the year ended December 31, 2019, the Company incurred reimbursable out-of-pocket expenses of $1.1 million for professional services obtained from a provider whose board of directors included a member who was also a member of the Company’s Board. These expenses are included within direct costs in the consolidated statements of income. This provider ceased to be a related party as of December 31, 2019.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	17. Commitments and Contingencies Legal Contingencies The Company is involved in various claims and legal actions 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, other than the specific matters described below, if decided adversely, is not expected to have a material adverse effect on the Company's business, financial condition, results of operations, or cash flows. On December 1, 2017, the first of two virtually identical actions alleging federal securities law claims was filed against the Company and certain of its officers on behalf of a putative class of its shareholders. The first action, captioned Bermudez v. INC Research, Inc., et al, No. 17-09457 (S.D.N.Y.), was filed in the Southern District of New York (the “Bermudez action”), and the second action, Vaitkuvienë v. Syneos Health, Inc., et al, No. 18-0029 (E.D.N.C.), was filed on January 25, 2018 in the Eastern District of North Carolina (the “Vaitkuvienë action”). On March 30, 2018, the Bermudez action was dismissed voluntarily. After the San Antonio Fire & Police Pension Fund and El Paso Firemen & Policemen’s Pension Fund were appointed as Lead Plaintiffs in the Vaitkuvienë action, Lead Plaintiffs filed an amended complaint on July 30, 2018, which named as defendants the Company, Alistair Macdonald, Gregory S. Rush, Michael A. Bell, and each member of the Company’s Board at the time of the stockholder vote on the 2017 merger (the “Merger”) of INC Research with an affiliate of inVentiv Health, Inc. (“inVentiv”). The amended complaint alleged claims under Sections 10(b), 14(a) and 20(a) of the Securities Exchange Act of 1934 on behalf of a putative class of purchasers of the Company’s common stock between May 10, 2017 and November 8, 2017, contending that the Company published inaccurate or incomplete information regarding, among other things, the financial performance and business outlook for inVentiv’s business prior to and following the Merger. Lead Plaintiffs seek, among other things, orders (i) declaring that the lawsuit is a proper class action and (ii) awarding compensatory damages in an amount to be proven at trial, including interest thereon, and reasonable costs and expenses incurred in this action, including attorneys’ fees and expert fees, to Lead Plaintiffs and other class members. On September 20, 2018, Defendants moved to dismiss the action. On August 30, 2021, the District Court entered an order granting the motion to dismiss in its entirety, and on October 21, 2021, the Court entered judgment for Defendants. On November 19, 2021, Lead Plaintiffs appealed from this judgment to the U.S. Court of Appeals for the Fourth Circuit, which appeal remains pending. The Company is presently unable to predict the duration, scope, or result of the foregoing putative class actions, or any other related lawsuit. As such, the Company is presently unable to develop a reasonable estimate of a possible loss or range of losses, if any, related to these matters. While the Company intends to defend any further proceedings in the putative class action litigation vigorously, the outcome of such litigation or any other litigation is necessarily uncertain. The Company could be forced to expend significant resources in the defense of these lawsuits or future ones, and it may not prevail. As such, these matters could have a material adverse effect on the Company's business, annual, or interim results of operations, cash flows, or its financial condition. Assumed Contingent Tax-Sharing Obligation As a result of the Merger, the Company assumed contingent tax-sharing obligations arising from inVentiv Health, Inc.’s 2016 merger with Double Eagle Parent, Inc. During the first quarter of 2021, the Company made payments of $6.2 million to fully settle this outstanding obligation. As of December 31, 2020, the estimated fair value of the assumed contingent tax-sharing obligations was $6.8 million. Contingent Earn-out Liabilities In connection with the RxDataScience acquisition, the Company recorded a contingent earn-out liability to be paid based on achievement of revenue targets in 2022 and the renewal of a specific customer contract. The estimated fair value of the contingent earn-out liability as of December 31, 2021 was $14.6 million and was included in other long-term liabilities in the accompanying consolidated balance sheet. For additional information, refer to “Note 3 - Acquisitions, Divestitures, and Investments.” In connection with an insignificant acquisition in 2021, the Company recorded a contingent earn-out liability to be paid based on achievement of employee retention benchmarks. The estimated fair value of the contingent obligation was $3.4 million as of December 31, 2021 and was included in accrued expenses in the accompanying consolidated balance sheet.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	18. Share-Based Compensation Overview of Employee Share-Based Compensation Plans The Company has two share-based compensation plans, the Syneos Health, Inc. 2018 Equity Incentive Plan (“2018 Plan”) and the Syneos Health, Inc. 2016 Employee Stock Purchase Plan, as amended and restated ( “ ” “ ” “ ” “ ” three-year As of December 31, 2021, the maximum number of shares reserved for issuance under the Company’s share-based compensation plans was 15,167,325, of which 3,446,778 shares were available for future grants as of December 31, 2021. In addition, under the 2018 Plan, any shares of the Company’s common stock that are retained by or returned to the Company under any outstanding awards that are canceled, expired, forfeited, surrendered, settled in cash, or otherwise terminated without delivery of the shares, in each case, will prior to vesting or exercise become available for future grants. Employee Stock Purchase Plan In March 2016, the Board approved the ESPP, which was also approved by the Company’s shareholders in May 2016. The ESPP was subsequently amended and restated and approved by the Board in March 2018, and also approved by the Company’s shareholders in May 2018. The ESPP allows eligible employees to authorize payroll deductions of up to 10% of their annual base salary or wages to be applied toward the purchase of full shares of the Company’s common stock on the last trading day of the offering period. Participating employees can purchase shares of the Company’s common stock at a 15% discount to the lesser of the closing price of the Company’s common stock as quoted on the Nasdaq Stock Exchange on (i) the first trading day of the offering period or (ii) the last trading day of the offering period. Offering periods under the ESPP are six months in duration, and the first offering period began on September 1, 2016. Under the ESPP, the Company recognized share-based compensation expense of $6.2 million, $5.8 million, and $6.5 million for the years ended December 31, 2021, 2020, and 2019, respectively. As of December 31, 2021, there were 1,594,312 shares issued and 1,905,688 shares reserved for future issuance under the ESPP. The fair values of ESPP offerings were determined using the Black-Scholes valuation model and the following assumptions: Year Ended December 31, 2021 2020 2019 Expected volatility 25.3% - 38.3% 27.7% - 55.1% 39.1% - 51.9% Risk-free interest rate 0.06% - 0.07% 0.13% - 0.95% 1.88% - 2.52% Expected term (in years) 0.5 0.5 0.5 Stock Option Awards The following table sets forth the summary of stock option activity for the year ended December 31, 2021: Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands)(a) Outstanding as of December 31, 2020 663,559 $ 30.12 Exercised (279,072 ) 33.31 Forfeited — — Outstanding as of December 31, 2021 384,487 27.81 3.26 $ 28,787 Vested and expected to vest as of December 31, 2021 384,487 27.81 3.26 $ 28,787 Exercisable as of December 31, 2021 384,487 27.81 3.26 $ 28,787 (a) Represents the total pre-tax intrinsic value (i.e., the aggregate difference between the closing price of the Company’s common stock on December 31, 2021 of $102.68 and the exercise price for in-the-money options) that would have been received by the holders if all instruments had been exercised on December 31, 2021. As of December 31, 2021, there was no unrecognized compensation expense related to non-vested stock options. There have been no stock options granted since 2017. The total intrinsic value of options exercised was $14.7 million, $12.7 million, and $20.3 million for the years ended December 31, 2021, 2020, and 2019, respectively. Restricted Stock Units Awards The following table sets forth a summary of RSUs outstanding under the 2014 and 2018 Plans as of December 31, 2021 and changes during the year then ended: Time-based Performance-based Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Total Number of Shares Non-vested as of December 31, 2020 1,909,882 $ 51.98 461,499 $ 48.99 2,371,381 Granted 939,031 76.96 59,055 75.43 998,086 Vested (997,632 ) 48.45 (136,665 ) 46.47 (1,134,297 ) Forfeited (226,094 ) 64.07 (27,890 ) 58.71 (253,984 ) Non-vested as of December 31, 2021 1,625,187 $ 66.90 355,999 $ 60.75 1,981,186 Unrecognized compensation expense (in millions) $ 62.6 $ 10.7 Weighted average period unrecognized compensation is expected to be recognized 1.9 years 1.9 years Time-based Awards The weighted-average grant-date fair value of the RSUs granted during the years ended December 31, 2020 and 2019 was $62.12 Performance-Based Awards During the years ended December 31, 2021, 2020, and 2019, the Board and Compensation and Management Development Committee granted certain executive officers performance-based RSUs (“PRSUs”). The PRSUs are subject to the Company’s achieving certain performance targets including revenue growth, adjusted diluted EPS growth, and return on invested capital. Compensation expense related to PRSUs is recorded based on the estimated quantity of awards that are expected to vest. At each reporting period, management re-assesses the probability that the performance conditions will be achieved and adjusts compensation expense to reflect any changes in the estimated probability of vesting until the actual level of achievement of the performance targets is known. The weighted-average grant-date fair value of the PRSUs granted during the years ended December 31, 2020 and 2019 was $62.50 and $45.00, respectively. The total fair value of shares vested during the year ended December 31, 2021, was $6.4 million. No PRSUs were vested or distributed in the years ended December 31, 2020 and 2019. Share-Based Compensation Expense Total share-based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Direct costs $ 33,220 $ 31,347 $ 29,011 Selling, general, and administrative expenses 31,984 27,144 26,182 Total share-based compensation expense $ 65,204 $ 58,491 $ 55,193 The total income tax benefit recognized in the consolidated statements of income for share-based compensation arrangements was approximately $13.8 million, $11.8 million, and $10.8 million for the years ended December 31, 2021, 2020, and 2019, respectively.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans	19. Employee Benefit Plans Defined Contribution Retirement Plans In the U.S., the Company offers defined contribution retirement benefit plans that comply with Section 401(a) of the Internal Revenue Code under which it matches employee deferrals at varying percentages and at specified limits of the employee’s salary. In 2020, the Company implemented cost management strategies, including suspending the Company match on U.S. employee 401(k) contributions for six months. The match was resumed in the fourth quarter of 2020. The Company’s contributions related to these defined contribution retirement plans were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Defined contribution retirement plan contributions $ 30,932 $ 15,049 $ 29,834 The Company also has defined contribution retirement plans outside of the U.S. The Company’s contributions related to these plans were approximately $23.2 million, $18.4 million, and $10.0 million for the years ended December 31, 2021, 2020, and 2019, respectively. The Company’s contributions associated with all of its defined contribution retirement plans are recorded in direct costs and selling, general, and administrative expenses on the accompanying consolidated statements of income. Deferred Compensation Plan The Company offers a Nonqualified Deferred Compensation Plan for certain employees pursuant to Section 409A of the Internal Revenue Code (“NQDC Plan”). Under this plan, participants can defer, on a pre-tax basis, from 1.0% up to a maximum of 80.0% of salary and from 1.0% up to a maximum of 100.0% of commissions and annual bonuses. The Company does not make matching contributions into the NQDC Plan. Distributions will be made to participants upon termination of employment or death in a lump sum, unless installments are selected. As of December 31, 2021 and 2020, the NQDC Plan deferred compensation liabilities were $23.4 million

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ( “ ”
Reclassification	Reclassification Certain previously reported amounts have been reclassified to conform to the current year presentation.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions. These estimates and assumptions affect the reported amounts of assets and liabilities and the disclosures of contingent assets and liabilities as of the date of the financial statements, and the reported amounts of revenue and expenses for the periods presented in the financial statements. Examples of estimates and assumptions include, but are not limited to, determining the fair value of goodwill and intangible assets and their potential impairment, useful lives of tangible and intangible assets, useful lives of assets subject to leases, valuation of the Company’s right of use assets, allowances for doubtful accounts, potential future outcomes of events for which income tax consequences have been recognized in the Company’s consolidated financial statements or tax returns, valuation allowances for deferred tax assets, fair value of share-based compensation and its recognition period, loss contingencies, fair value of derivative instruments and related hedge effectiveness, fair value of contingent tax sharing obligations, and judgments related to revenue recognition, among others. In addition, estimates and assumptions are used in the accounting for acquisitions, including the fair value and useful lives of acquired tangible and intangible assets and the fair value of assumed liabilities. The Company evaluates its estimates and assumptions on an ongoing basis and bases its estimates on historical experience, current and expected future conditions, third-party evaluations, and various other assumptions that management believes are reasonable under the circumstances based on the information available to management at the time these estimates and assumptions are made. Actual results and outcomes may differ significantly from these estimates and assumptions.
Acquisitions	Acquisitions The Company accounts for acquisitions in accordance with ASC Topic 805, Business Combinations “ ”
Foreign Currency Translation and Transactions	Foreign Currency Translation and Transactions For subsidiaries outside of the U.S. that operate in a local currency environment, revenue and expenses are translated to U.S. dollars at the monthly average rates of exchange prevailing during the period, assets and liabilities are translated at period-end exchange rates, and equity accounts are translated at historical exchange rates. The net effect of foreign currency translation adjustments is included in shareholders’ equity as a component of accumulated other comprehensive loss in the accompanying consolidated balance sheets. Foreign currency transaction gains and losses are the result of exchange rate changes during the period of time between the consummation and cash settlement of transactions denominated in currencies other than the functional currency. Foreign currency transaction gains and losses are recognized in earnings as incurred and are included in other (income) expense, net in the accompanying consolidated statements of income.
Comprehensive Income	Comprehensive Income Comprehensive income
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of demand deposits with banks and other financial institutions and highly liquid investments with an original maturity of three months or less at the date of purchase. Cash and cash equivalents are carried at cost, which approximates their fair value. Certain of the Company’s subsidiaries participate in a notional cash pooling arrangement to manage global liquidity requirements. As part of a master netting arrangement, the participants combine their cash balances in pooling accounts at the same financial institution with the ability to offset bank overdrafts of one participant against positive cash account balances held by another participant. Under the terms of the master netting arrangement, the financial institution has the right, ability, and intent to offset a positive balance in one account against an overdrawn amount in another account. Amounts in each of the accounts are unencumbered and unrestricted with respect to use. As such, the net cash balance related to this pooling arrangement is included in cash, cash equivalents, and restricted cash in the accompanying consolidated balance sheets. The Company’s net cash pool position consisted of the following as of December 31 (in thousands): 2021 2020 Gross cash position $ 179,160 $ 220,261 Less: cash borrowings (167,507 ) (204,647 ) Net cash position $ 11,653 $ 15,614
Restricted Cash	Restricted Cash Restricted cash represents cash and deposits held as security over bank deposits, lease guarantees, and insurance obligations that are restricted as to withdrawal or use. Restricted cash is classified as a current or long-term asset based on the timing and nature of when and how the cash is expected to be used or when the restrictions are expected to lapse. As of December 31, 2021 and 2020, restricted cash balances were $0.1 million and $0.3 million, respectively.
Fair Value	Fair Value The Company records certain assets and liabilities at fair value in accordance with ASC Topic 820, Fair Value Measurement “ ” Level 1 – Unadjusted quoted prices in active markets for identical instruments; Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs or significant value-drivers are observable in active markets; and Level 3 – Model-derived valuations in which one or more significant inputs or significant value-drivers are unobservable, including internally developed models.
Derivative Financial Instruments	Derivative Financial Instruments Interest Rate Swaps The Company uses interest rate swaps to manage exposure to variable interest rates on its debt obligations. The Company designates its interest rate swaps as cash flow hedges because they are executed to hedge the Company’s exposure to the variability in expected future cash flows that are attributable to changes in interest rates. Derivative financial instruments are measured at fair value and recognized in the accompanying consolidated balance sheets in prepaid expenses and other current assets, other long-term assets, accrued expenses, and other long-term liabilities, as disclosed in “ ” Foreign Exchange Forward The Company utilizes a foreign exchange forward in order to minimize monthly foreign currency remeasurement gains or losses on non-functional currency monetary balances. The Company did not designate the derivative as a hedge. All changes in the fair value of the foreign exchange forward are recorded in earnings every month to other (income) expense, net in the accompanying consolidated statements of income “ ”
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company maintains a credit approval process and makes judgments in connection with assessing its customers’ ability to pay for contracted services. Generally, the Company has the ability to limit credit exposure by discontinuing services in the event of non-payment. The Company monitors its customers’ credit worthiness and applies judgment in establishing a provision for estimated credit losses based on historical experience, the aging of receivables, and customer-specific circumstances that would affect the customers’ ability to pay for services rendered.
Property and Equipment	Property and Equipment Property and equipment primarily consists of furniture, vehicles, software, office equipment, computer equipment, and lab equipment. Purchased and constructed property and equipment is initially recorded at historical cost plus the estimated value of any associated legally or contractually required retirement obligations. Property and equipment acquired in an acquisition are recorded based on the estimated fair value as of the acquisition date. The Company leases vehicles for certain sales representatives in the Commercial Solutions segment. These leases are classified and accounted for as leases in accordance with ASC Topic 842, Leases “ ” “ ” Property and equipment assets are depreciated using the straight-line method over the respective estimated useful lives as follows: Useful Life Buildings 39 years Furniture and fixtures 7 years Equipment 5 to 10 years Computer equipment and software 2 to 3 years Vehicles Lesser of lease term or the estimated economic life of the leased asset Leasehold improvements Lesser of remaining life of lease or the useful life of the asset Expenditures for repairs and maintenance are expensed as incurred and expenditures for major improvements that increase the functionality or extend the useful life of the asset are capitalized and depreciated over the estimated useful life of the asset. The Company capitalizes costs of computer software obtained for internal use and amortizes these costs on a straight-line basis over the estimated useful life of the product, not to exceed five years. Software cloud computing arrangements containing a software license are accounted for consistently with the acquisition of other software licenses. In the event such an arrangement does not contain a software license, the Company accounts for the arrangement as a service contract. The Company reviews property and equipment for impairment whenever facts and circumstances indicate that the carrying amounts of these assets might not be recoverable. For assessment purposes, property and equipment are grouped with other assets and liabilities at the lowest level that identifiable cash flows are largely independent of the cash flows of other assets and liabilities. Recoverability of the carrying amount of an asset group is assessed by comparing its carrying amount to the estimated undiscounted future cash flows expected to be generated by the asset group. If the carrying value of the asset group exceeds its fair value, an impairment charge is recognized for the excess.
Leases	Leases At inception, a contract contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. In evaluating whether it has the right to control the use of an identified asset, the Company assesses whether they have the right to direct the use of the identified asset and to obtain substantially all of the economic benefit from the use of the identified asset. Right-of-use ( “ ” ’ ’ ’ Because most of the Company ’ The Company has agreements with lease and non-lease components, which are accounted for as a single lease component. Leases with a lease term of 12 months or less are not recorded on the balance sheet. The Company recognizes lease expense for these leases on a straight-line basis over the lease term. Variable lease payment amounts that cannot be determined at the commencement of the lease, such as increases in lease payments based on changes in index rates, are not included in the right-of-use assets or liabilities. These variable lease payments are expensed as incurred.
Goodwill and intangible assets	Goodwill and Intangible Assets Goodwill represents the excess of the purchase price over the estimated fair value of net assets acquired, including the amount assigned to identifiable intangible assets, in acquisitions. In accordance with ASC Topic 350, Intangibles Goodwill and Other The Company has assigned goodwill to four reporting units. The Company completed an annual impairment test as of October 1, 2021 for all of its reporting units, and concluded that there were no impairments. Intangible assets consist of customer relationships, acquired backlog, trade names, trademarks, patient communities, and acquired technologies. The Company amortizes intangible assets related to customer relationships, trade names, trademarks, patient communities, and acquired technologies on a straight-line basis over the estimated useful life of the asset. Intangible assets related to acquired backlog are amortized based on the Company’s expectations of the timing of when revenue associated with the backlog is expected to be recognized. The Company reviews intangible assets at the end of each reporting period to determine if facts and circumstances indicate that the useful life is shorter than originally estimated or that the carrying amount of the assets might not be recoverable. If such facts and circumstances exist, the Company assesses the recoverability of identified assets by comparing the projected undiscounted cash flows associated with the related asset or group of assets to their respective carrying amounts. Impairments, if any, are based on the excess of the carrying amount over the fair value of those assets and occur in the period in which the impairment determination is made. The weighted average estimated useful lives of the Company’s intangible assets were as follows as of December 31: 2021 2020 Customer relationships 9.8 years 9.9 years Acquired backlog 2.6 years 2.6 years Trade names and trademarks 5.5 years 5.5 years Intellectual property (medical patent) n/a 9.0 years Patient communities 6.0 years n/a Acquired technologies 6.0 years n/a No intangible asset impairment charges were recorded for the years ended December 31, 2021 or 2020. For additional information regarding the carrying values of intangible assets, see “ ”
Contingencies	Contingencies In the normal course of business, the Company periodically becomes involved in various proceedings and claims, including investigations, disputes, litigations, and regulatory matters that are incidental to its business. The Company evaluates the likelihood of an unfavorable outcome of all legal and regulatory matters and records accruals for probable loss contingencies for which the amount of the loss can be reasonably estimated. Gain contingencies are not recognized until realized. Legal fees are expensed as incurred. Because these matters are inherently unpredictable, and unfavorable developments or resolutions can occur, assessing contingencies is highly subjective and requires judgments about future events. These judgments and estimates are based, among other factors, on the status of the proceedings, the merits of the Company’s defenses, and the consultation with in-house and external counsel. The Company regularly reviews contingencies to determine whether its accruals and related disclosures are adequate. Although the Company believes that it has substantial defenses in these matters, the amount of losses incurred as a result of actual outcomes may differ significantly from the Company’s estimates.
Revenue Recognition	Revenue Recognition In accordance with ASC Topic 606, Revenue from Contracts with Customers A performance obligation is a promise (or a combination of promises) in a contract to transfer distinct goods or services to a customer and is the unit of accounting under ASC 606 for the purposes of revenue recognition. A contract’s transaction price is allocated to each performance obligation and is recognized as revenue, when, or as, each performance obligation is satisfied. The majority of the Company’s Clinical Solutions segment contracts have a single performance obligation because the promise to transfer individual services is not separately identifiable from other promises in the contracts, and therefore, is not distinct. For contracts with multiple performance obligations, the contract’s transaction price is allocated to each performance obligation using the best estimate of the standalone selling price of each distinct good or service in the contract. The majority of the Company’s revenue arrangements are service contracts that range in duration from a few months to several years. Substantially all of the Company’s performance obligations, and associated revenue, are transferred to the customer over time. The Company generally receives compensation based on measuring progress toward completion using anticipated project budgets for direct labor and prices for each service offering. The Company is also reimbursed for certain third-party pass-through and out-of-pocket costs. In addition, in certain instances a customer contract may include forms of variable consideration such as incentive fees, volume rebates or other provisions that can increase or decrease the transaction price. This variable consideration is generally awarded upon achievement of certain performance metrics, program milestones or cost targets. For the purposes of revenue recognition, variable consideration is assessed on a contract-by-contract basis and the amount included in the transaction price is estimated based on the Company’s anticipated performance and consideration of all information that is reasonably available. Variable consideration is recognized as revenue if and when it is deemed probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved in the future. Most of the Company’ s contracts can be terminated by the customer without cause with a notice period that generally ranges from 30 to 90 day s . In the event of termination, the Company’ s contracts generally provide that the customer pay the Company for: (i) fees earned through the termination date; (ii) fees and expenses for winding down the project, which include both fees incurred and actual expenses; (iii) non-cancellable expenditures; and (iv) in some cases, a fee to cover a portion of the remaining professional fees on the project . The Company’s long-term clinical trial contracts contain implied substantive termination penalties because of the significant wind-down cost of terminating a clinical trial. These provisions for termination penalties result in these types of contracts being treated as long-term for revenue recognition purposes. Changes in the scope of work are common, especially under long-term contracts, and generally result in a change in the total contract transaction price. If the customer does not agree to a contract modification, the Company could bear the risk of cost overruns. Most of the Company’s contract modifications are for services that are not distinct from the services under the existing contract due to the significant integration service provided in the context of the contract and therefore result in a cumulative catch-up adjustment to revenue at the date of contract modification. Capitalized Costs The Company capitalizes certain costs associated with commissions and bonuses paid to its employees in the Clinical Solutions segment because these costs are incurred in obtaining contracts that have a term greater than one year. Capitalized costs are included in prepaid expenses and other current assets and other long-term assets in the accompanying consolidated balance sheets. The Company amortizes these costs in a manner that is consistent with the pattern of revenue recognition described below. The Company expenses costs to obtain contracts that have a term of one year or less. Clinical Solutions The Company’s Clinical Solutions segment provides solutions to address the clinical development needs of customers. The Company provides total biopharmaceutical program development through its full-service platform, while also providing discrete services for any part of a clinical trial, primarily through functional service provider, Early Stage, and Real World and Late Phase (“RWLP”) services. The services provided via the full-service platform and RWLP platforms generally span several years and a significant benefit to the customer is provided by integrating the services provided by the Company’s employees as well as those performed by third parties. Because the Company’s full-service platform provides a significant integration service to the customer, these contracts contain a single performance obligation. Revenue is recognized over time using an input measure of progress. The input measure reflects costs (including investigator payments and pass-through costs) incurred to date relative to total estimated costs to complete (“cost-to-cost measure of progress”). Under the cost-to-cost measure of progress methodology, revenue is recorded proportionally to costs incurred. Contract costs principally include direct labor, investigator payments, and pass-through costs. The estimate of total estimated costs at completion requires significant judgment. Contract estimates are based on various assumptions to project future outcomes of events that often span several years. These estimates are reviewed periodically and any adjustments are recognized on a cumulative catch-up basis in the period they become known. The remaining service offerings within the Clinical Solutions segment are generally short-term, month-to-month contracts, time and materials basis contracts, or provide a series of distinct services that are substantially the same and have the same pattern of transfer to the customer (“series”). As such, revenue for these service offerings is generally recognized as services are performed for the amount the Company estimates it is entitled to for the period. Commercial Solutions The Company’s Commercial Solutions segment provides a broad suite of complementary commercialization services including Deployment Solutions, communications (advertising and public relations), and consulting services. Deployment Solutions contracts offer outsourced services to promote commercial products on behalf of a customer. The remaining Commercial Solutions contracts are generally short-term, month-to-month contracts or time and materials contracts. As such, Commercial Solutions revenue is generally recognized as services are performed for the amount of consideration the Company estimates it is entitled to for the period. For contracts billed on a fixed price basis, revenue is recognized over time based on the proportion of labor costs expended to total labor costs expected to complete the contract. Accounts Receivable, Unbilled Services, and Deferred Revenue Accounts receivable are recorded at net realizable value. Unbilled accounts receivable arise when services have been rendered for which revenue has been recognized but the customers have not been billed. Contractual provisions and payment schedules may or may not correspond to the timing of the performance of services under the contract. Unbilled services include contract assets, under which the right to bill the customer is subject to factors other than the passage of time. These amounts may not exceed their net realizable value. Contract assets are generally classified as current. Deferred revenue is a contract liability that consists of customer payments received in advance of performance and billings in excess of revenue recognized, net of revenue recognized from the balance at the beginning of the period. Timing of Billing and Performance Differences in the timing of revenue recognition and associated billings and cash collections result in recording of billed accounts receivable, unbilled accounts receivable (including contract assets), and deferred revenue on the consolidated balance sheet. Amounts are billed as work progresses in accordance with agreed-upon contractual terms either at periodic intervals or upon achievement of contractual milestones. Billings generally occur subsequent to revenue recognition, resulting in recording unbilled accounts receivable in instances where the right to bill is contingent solely on the passage of time (e.g., in the following month), and contract assets in instances where the right to bill is associated with achievement of a milestone.
Reimbursable Out-of-pocket Expenses	Reimbursable Out-of-Pocket Expenses The Company incurs and is reimbursed by its customers for certain costs, including fees paid to principal investigators and for other out-of-pocket costs (such as travel expenses for the Company’s clinical monitors and sales representatives). The Company includes these costs in total operating expenses, and the related reimbursements in revenue, as the Company is the principal in the applicable arrangements and is responsible for fulfilling the promise to provide the specified services.
Share-Based Compensation	Share-Based Compensation The Company measures and recognizes compensation expense related to all share-based awards based on the estimated fair value of the awards. The fair value of restricted stock and stock unit awards is measured on the grant date based on the fair market value of the Company’s common stock. Share-based compensation expense is recognized on a straight-line basis over the shorter of the requisite service period or the vesting term. For awards with performance conditions, stock-based compensation expense is recognized when the achievement of each individual performance target becomes probable, and the number of shares expected to vest is adjusted for the weighted probability of attainment of the relevant performance targets. Forfeitures are accounted for as they occur. All excess tax benefits and tax deficiencies (including tax benefits of dividends on share-based payment awards, if applicable) are recognized as income tax expense or benefit in the consolidated statements of income. The tax effects of exercised or vested awards are treated as discrete items in the reporting period in which they occur. The Company also recognizes excess tax benefits regardless of whether the benefit reduces taxes payable in the current period.
Income Taxes	Income Taxes The majority of the Company’s U.S. subsidiaries file a consolidated U.S. federal income tax return, while certain U.S. subsidiaries, including recently acquired entities, may file separate U.S. federal tax returns. The Company’s subsidiaries in international jurisdictions file tax returns in their respective jurisdictions. The Company estimates its tax liability based on current tax laws in the statutory jurisdictions in which it operates. Accordingly, the impact of changes in income tax laws on deferred tax assets and deferred tax liabilities is recognized in earnings in the period during which such changes are enacted. The Company records deferred tax assets and liabilities based on temporary differences between the financial reporting basis and tax basis of the Company’s assets and liabilities at enacted tax rates expected to be in effect when the differences are realized or settled. Deferred income tax assets represent amounts available to reduce income taxes payable on taxable income in future years. Such assets arise because of temporary differences between the financial reporting and tax bases of assets and liabilities, as well as from net operating loss and tax credit carryforwards. The Company evaluates recoverability of these future tax deductions. The Company establishes a valuation allowance for deferred income tax assets when the Company believes it is more likely than not the assets will not be realized. The Company evaluates the recoverability of these future tax deductions by assessing future expected taxable income. In estimating future taxable income, the Company considers both positive and negative evidence, such as historical and forecasted results of operations, and implementation of prudent and feasible tax planning strategies. If the objectively verifiable negative evidence outweighs any available positive evidence (or the only available positive is subjective and cannot be verified), then a valuation allowance will likely be deemed necessary. If a valuation allowance is deemed to be unnecessary, such allowance is released and any related benefit is recognized in the period of the change. The Company recognizes a tax benefit from any uncertain tax positions only if they are more likely than not to be sustained upon examination based on the technical merits of the position. The Company evaluates uncertain tax positions pursuant to the more likely than not standard, and benefits related to such uncertain tax positions are recognized as the largest amount of benefit, determined on a cumulative probability basis, to be realized upon ultimate settlement of the position. Components of the reserve for uncertain tax positions are classified as either a current or a long-term liability in the accompanying consolidated balance sheets based on management’s expectation of future cash settlements. Judgment is required in determining what constitutes an uncertain tax position, as well as assessing the outcome of each tax position. The Company considers many factors when evaluating and estimating tax positions and tax benefits. In addition, the calculation of tax liabilities involves dealing with uncertainties in the application of complex tax regulations in domestic and foreign jurisdictions. If the calculation of the liability related to uncertain tax positions proves to be more or less than the ultimate settlement, a tax expense or tax benefit, respectively, would result. Unrecognized tax benefits are presented as either a reduction to a deferred tax asset or as a separate liability.
Restructuring and Other Costs	Restructuring and Other Costs Restructuring and other costs primarily consist of one-time employee termination benefits, contract termination costs, and other costs associated with an exit or disposal activity. The Company accounts for restructuring costs in accordance with ASC Topic 420, Exit or Disposal Cost Obligations
Earnings Per Share	Earnings Per Share The Company determines earnings per share in accordance with ASC Topic 260, Earnings Per Share
Subsequent Events	Subsequent Events The Company considers events or transactions that occur after the balance sheet date but before the financial statements are issued to provide additional evidence relative to certain estimates or to identify matters that require additional disclosure. The Company evaluated all events and transactions through the date that these financial statements were issued.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2016-13 (“ASU 2016-13”), Financial Instruments - Credit Losses (Topic 326) to modify the impairment model to utilize an expected loss methodology in place of the previous incurred loss methodology and require consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The Company adopted ASU 2016-13 on January 1, 2020, and recorded the impact of the adoption through a cumulative-effect adjustment to accumulated deficit. for reporting periods beginning on January 1, 2020 are presented under ASU No. 2016-13, while prior period amounts continue to be reported and disclosed in accordance with the Company’s historical accounting treatment. Adoption of the new standard resulted in the recording of additional allowance for doubtful accounts of approximately $2.8 million as of January 1, 2020.

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule Of Cash Pool Position	The Company’s net cash pool position consisted of the following as of December 31 (in thousands): 2021 2020 Gross cash position $ 179,160 $ 220,261 Less: cash borrowings (167,507 ) (204,647 ) Net cash position $ 11,653 $ 15,614
Estimated Useful Lives of Property and Equipment	Property and equipment assets are depreciated using the straight-line method over the respective estimated useful lives as follows: Useful Life Buildings 39 years Furniture and fixtures 7 years Equipment 5 to 10 years Computer equipment and software 2 to 3 years Vehicles Lesser of lease term or the estimated economic life of the leased asset Leasehold improvements Lesser of remaining life of lease or the useful life of the asset Property and equipment, net of accumulated depreciation, consisted of the following as of December 31 (in thousands): 2021 2020 Software $ 159,736 $ 129,731 Leasehold improvements 96,188 94,596 Computer equipment 91,937 108,230 Vehicles 77,674 63,985 Office furniture, fixtures, and equipment 65,018 37,287 Buildings and land 5,692 5,211 Assets not yet placed in service 28,706 28,129 Property and equipment, gross 524,951 467,169 Less: Accumulated depreciation (302,294 ) (250,969 ) Property and equipment, net $ 222,657 $ 216,200
Estimated Useful Lives of Intangible Assets	The weighted average estimated useful lives of the Company’s intangible assets were as follows as of December 31: 2021 2020 Customer relationships 9.8 years 9.9 years Acquired backlog 2.6 years 2.6 years Trade names and trademarks 5.5 years 5.5 years Intellectual property (medical patent) n/a 9.0 years Patient communities 6.0 years n/a Acquired technologies 6.0 years n/a

Financial Statement Details (Ta

Financial Statement Details (Tables)	12 Months Ended
	Dec. 31, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Billed Accounts Receivable, Net	Accounts receivable and unbilled services (including contract assets), net of allowance for doubtful accounts, consisted of the following as of December 31 (in thousands): 2021 2020 Accounts receivable billed $ 873,265 $ 774,605 Accounts receivable unbilled 241,799 211,285 Contract assets 417,411 366,506 Less: Allowance for doubtful accounts (7,585 ) (7,615 ) Accounts receivable and unbilled services, net $ 1,524,890 $ 1,344,781
Schedule of Changes in the Allowance for Doubtful Accounts	The following table summarizes the changes in the allowance for doubtful accounts (in thousands): Year Ended December 31, 2021 2020 2019 Balance at the beginning of the period $ (7,615 ) $ (5,381 ) $ (4,587 ) Impact from adoption of ASU 2016-13 — (2,771 ) — Current year provision (367 ) (695 ) (1,897 ) Write-offs, net of recoveries and the effects of foreign currency exchange 397 1,232 1,103 Balance at the end of the period $ (7,585 ) $ (7,615 ) $ (5,381 )
Estimated Useful Lives of Property and Equipment	Property and equipment assets are depreciated using the straight-line method over the respective estimated useful lives as follows: Useful Life Buildings 39 years Furniture and fixtures 7 years Equipment 5 to 10 years Computer equipment and software 2 to 3 years Vehicles Lesser of lease term or the estimated economic life of the leased asset Leasehold improvements Lesser of remaining life of lease or the useful life of the asset Property and equipment, net of accumulated depreciation, consisted of the following as of December 31 (in thousands): 2021 2020 Software $ 159,736 $ 129,731 Leasehold improvements 96,188 94,596 Computer equipment 91,937 108,230 Vehicles 77,674 63,985 Office furniture, fixtures, and equipment 65,018 37,287 Buildings and land 5,692 5,211 Assets not yet placed in service 28,706 28,129 Property and equipment, gross 524,951 467,169 Less: Accumulated depreciation (302,294 ) (250,969 ) Property and equipment, net $ 222,657 $ 216,200
Schedule of Goodwill	The changes in carrying amount of goodwill by segment were as follows (in thousands): Clinical Solutions (a) Commercial Solutions (b) Total Balance as of December 31, 2019 $ 2,784,952 $ 1,565,428 $ 4,350,380 Acquisitions and divestitures (c) 418,619 (14,453 ) 404,166 Impact of foreign currency translation 12,764 8,868 21,632 Balance as of December 31, 2020 3,216,335 1,559,843 4,776,178 Acquisitions (d) 192,286 — 192,286 Impact of foreign currency translation and other (e) 40,078 (52,527 ) (12,449 ) Balance as of December 31, 2021 $ 3,448,699 $ 1,507,316 $ 4,956,015 (a) Accumulated impairment losses of $8.1 million associated with the Clinical Solutions segment were recorded prior to 2016 and related to the former Phase I Services segment, now a component of the Clinical Solutions segment. No impairment of goodwill was recorded for the years ended December 31, 2021, 2020, or 2019. (b) Accumulated impairment losses of $8.0 million associated with the Commercial Solutions segment were recorded prior to 2015 and related to the former Global Consulting segment, now a component of the Commercial Solutions segment. No impairment of goodwill was recorded for the years ended December 31, 2021, 2020, or 2019. (c) Amounts represent goodwill recognized in connection with the 2020 acquisitions of SHCR Holdings Corporation (“Synteract”) Illingworth Research Group™ (“Illingworth Research”) (d) Amount represents goodwill recognized in connection with the acquisitions of StudyKIK Corporation (“StudyKIK”) and RxDataScience, Inc. (“RxDataScience”), other insignificant acquisitions in 2021, and insignificant measurement period adjustments recognized in connection with the 2020 acquisitions of Synteract and Illingworth Research within the Clinical Solutions segment. (e) Includes $44.2 million reallocation of goodwill from the Commercial Solutions segment to the Clinical Solutions segment to reflect the transfer of the Kinapse Regulatory and Operations Consulting service lines to align with management reporting in 2021.
Schedule of Finite Lived Intangible Assets	Intangible assets, net consisted of the following (in thousands): December 31, 2021 December 31, 2020 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Customer relationships $ 1,547,925 $ (811,542 ) $ 736,383 $ 1,518,081 $ (685,021 ) $ 833,060 Acquired backlog 175,826 (154,475 ) 21,351 174,180 (132,733 ) 41,447 Trade names and trademarks 55,728 (28,806 ) 26,922 52,475 (21,817 ) 30,658 Intellectual property (medical patent) — — — 30,028 (1,668 ) 28,360 Patient communities 45,100 (2,192 ) 42,908 — — — Acquired technologies 27,800 (1,297 ) 26,503 — — — Intangible assets, net $ 1,852,379 $ (998,312 ) $ 854,067 $ 1,774,764 $ (841,239 ) $ 933,525
Schedule of Indefinite Lived Intangible Assets	Intangible assets, net consisted of the following (in thousands): December 31, 2021 December 31, 2020 Gross Accumulated Amortization Net Gross Accumulated Amortization Net Customer relationships $ 1,547,925 $ (811,542 ) $ 736,383 $ 1,518,081 $ (685,021 ) $ 833,060 Acquired backlog 175,826 (154,475 ) 21,351 174,180 (132,733 ) 41,447 Trade names and trademarks 55,728 (28,806 ) 26,922 52,475 (21,817 ) 30,658 Intellectual property (medical patent) — — — 30,028 (1,668 ) 28,360 Patient communities 45,100 (2,192 ) 42,908 — — — Acquired technologies 27,800 (1,297 ) 26,503 — — — Intangible assets, net $ 1,852,379 $ (998,312 ) $ 854,067 $ 1,774,764 $ (841,239 ) $ 933,525
Schedule of Future Amortization Expense	The future estimated amortization expense for intangible assets as of December 31, 2021 is expected to be as follows (in thousands): Year Ended December 31, 2022 $ 162,193 2023 153,334 2024 146,487 2025 132,512 2026 110,597 2027 and thereafter 148,944 Total $ 854,067
Schedule of Accrued Expenses	Accrued expenses consisted of the following as of December 31 (in thousands): 2021 2020 Professional fees, investigator fees, and pass-through costs $ 283,432 $ 231,638 Compensation, including bonuses, fringe benefits, and payroll taxes 215,386 255,042 Income and other taxes 25,723 28,890 Rebates to customers 22,367 22,528 Restructuring and other costs, current portion 6,657 5,830 Contingent obligations, current 3,397 4,327 Interest rate swaps - current 1,827 17,045 Other liabilities 55,652 45,742 Total accrued expenses $ 614,441 $ 611,042
Schedule of Accumulated Other Comprehensive Loss, Net of Tax	Accumulated other comprehensive loss, net of taxes, consisted of the following (in thousands): Year Ended December 31, 2021 2020 Beginning balance $ (40,801 ) $ (71,593 ) Derivative Instruments: Beginning balance (18,761 ) (14,836 ) Other comprehensive gain (loss) before reclassifications 2,963 (20,446 ) Reclassification adjustments 13,177 16,521 Ending balance (2,621 ) (18,761 ) Foreign Currency Translation: Beginning balance (22,040 ) (56,757 ) Other comprehensive (loss) income before reclassifications (24,957 ) 34,717 Ending balance (46,997 ) (22,040 ) Accumulated other comprehensive loss, net of taxes $ (49,618 ) $ (40,801 )
Reclassification out of Accumulated Other Comprehensive (Loss) Income	Changes in accumulated other comprehensive loss consisted of the following (in thousands): Year Ended December 31, 2021 2020 2019 Unrealized loss on derivative instruments: Unrealized gain (loss) during period, before taxes $ 4,084 $ (27,647 ) $ (14,306 ) Income tax expense (benefit) 1,121 (7,201 ) (2,777 ) Unrealized gain (loss) during period, net of taxes 2,963 (20,446 ) (11,529 ) Reclassification adjustment, before taxes 17,655 22,328 4,588 Income tax expense 4,478 5,807 655 Reclassification adjustment, net of taxes 13,177 16,521 3,933 Total unrealized gain (loss) on derivative instruments, net of taxes 16,140 (3,925 ) (7,596 ) Foreign currency translation adjustments: Foreign currency translation adjustments, before taxes (26,429 ) 36,071 24,198 Income tax (benefit) expense (1,472 ) 1,354 — Foreign currency translation adjustments, net of taxes (24,957 ) 34,717 24,198 Total other comprehensive (loss) income, net of taxes $ (8,817 ) $ 30,792 $ 16,602
Schedule of Other (Income) Expense, Net (Details)	Other (income) expense, net consisted of the following (in thousands): Year Ended December 31, 2021 2020 2019 Net realized foreign currency loss $ 2,190 $ 3,175 $ 11,853 Net unrealized foreign currency (gain) loss (5,928 ) 4,147 11,166 Gain on sale of business — (7,133 ) — Equity investment (income) expense (1,950 ) (3,745 ) 261 Other, net (2,945 ) 580 882 Total other (income) expense, net $ (8,633 ) $ (2,976 ) $ 24,162
Supplemental Disclosure of Cash Flow Information	The following table provides details of supplemental cash flow information (in thousands): Year Ended December 31, 2021 2020 2019 Cash paid for income taxes, net of refunds $ 35,100 $ 23,400 $ 12,200 Cash paid for interest (excluding finance leases) 63,952 83,690 129,756 Supplemental disclosure of noncash investing and financing activities Non-cash investment to acquire certain intellectual property rights from a customer in lieu of cash payment for services rendered — 27,300 — Fair value of contingent consideration related to acquisitions 19,158 — — Change in property and equipment included in liabilities 1,753 11,684 5,977 Vehicles acquired through finance lease agreements 28,994 20,203 37,701

Acquisitions, Divestitures, a_2

Acquisitions, Divestitures, and Investments (Tables)	12 Months Ended
	Dec. 31, 2021
Business Acquisition [Line Items]
Allocation of Consideration Transferred	The following table summarizes the estimated fair value of the net assets acquired at the date of the acquisition: Assets acquired: Cash and cash equivalents $ 28,028 Accounts receivable and unbilled services 39,723 Prepaid expenses and other current assets 2,160 Property and equipment 3,978 Operating lease right-of-use assets 10,839 Other identifiable intangible assets 56,400 Goodwill 363,733 Other assets 4,121 Total assets acquired 508,982 Liabilities assumed: Accounts payable and accrued expenses 25,623 Deferred revenue 45,272 Operating lease obligations 15,693 Deferred income taxes, net 7,754 Other liabilities 1,126 Total liabilities assumed 95,468 Net assets acquired $ 413,514
StudyKIK Acquisition [Member]
Business Acquisition [Line Items]
Preliminary Estimates of Fair Values of Intangible Assets and Estimated Useful Lives	The following table summarizes the fair values of identified intangible assets and their respective useful lives (dollars in thousands): Estimated Fair Value Estimated Useful Life Customer relationships $ 22,300 6 years Acquired backlog 1,800 1.25 years Trade name 2,700 6 years Patient communities 45,100 6 years Acquired technologies 19,900 6 years Total intangible assets $ 91,800
Synteract Acquisition [Member]
Business Acquisition [Line Items]
Preliminary Estimates of Fair Values of Intangible Assets and Estimated Useful Lives	The following table summarizes the fair value of identified intangible assets and their respective useful lives at the date of the acquisition (dollars in thousands): Estimated Fair Value Estimated Useful Life Acquired backlog $ 37,200 4 years Trade name 19,200 8 years Total intangible assets $ 56,400

Long-Term Debt Obligations (Tab

Long-Term Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of Debt Obligations	The Company’s debt obligations consisted of the following as of December 31 (in thousands): 2021 2020 Secured Debt Term Loan A - tranche one due March 2024 $ 149,195 $ 183,715 Term Loan A - tranche two due August 2024 1,636,797 1,273,991 Term Loan B due August 2024 — 560,564 Accounts receivable financing agreement due October 2024 400,000 300,000 Total secured debt 2,185,992 2,318,270 Unsecured Debt Senior notes due January 2029 (the “Notes”) 600,000 600,000 Total debt obligations 2,785,992 2,918,270 Less: Term loans original issuance discount (2,228 ) (3,500 ) Less: Unamortized deferred issuance costs (8,043 ) (12,716 ) Total long-term debt $ 2,775,721 $ 2,902,054 The applicable margins with respect to Alternate Base Rate and Adjusted Eurocurrency Rate borrowings are determined depending on the “First Lien Leverage Ratio” or the “ ” Alternate Base Rate Adjusted Eurocurrency Rate Term Loan A 0.25% - 0.50% 1.25% - 1.50% Term Loan B 0.75% - 1.00% 1.75% - 2.00% Revolver 0.25% - 0.50% 1.25% - 1.50%
Contractual Maturities of Debt Obligations	As of December 31, 2021, the contractual maturities of the Company’s debt obligations (excluding finance leases that are presented in “ ” 2022 $ — 2023 21,732 2024 2,164,260 2025 — 2026 — 2027 and thereafter 600,000 Less: Term loan original issuance discount (2,228 ) Less: Unamortized deferred issuance costs (8,043 ) Total $ 2,775,721

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Schedule of Lease, Cost	The components of lease cost were as follows for the year ended December 31 and the line items on the accompanying consolidated statements of income to which they were recorded were as follows (in thousands): Statement of Income Classification 2021 2020 Operating leases: Fixed lease costs Direct costs, selling, general, and administrative expenses and restructuring and other costs $ 55,168 $ 53,531 Short-term lease costs Direct costs and selling, general, and administrative expenses 1,994 2,930 Variable lease costs Direct costs, selling, general, and administrative expenses and restructuring and other costs 36,760 29,572 Total operating lease costs $ 93,922 $ 86,033 Finance leases: Amortization of right-of-use assets Depreciation $ 17,453 $ 15,843 Interest on lease liabilities Interest expense 605 944 Variable lease costs Direct costs 6,231 6,321 Total finance lease costs $ 24,289 $ 23,108
Schedule of Assets And Liabilities	Supplemental balance sheet information related to finance leases was as follows as of December 31 (in thousands): 2021 2020 Property and equipment, gross $ 77,674 $ 63,985 Accumulated depreciation (30,021 ) (20,479 ) Property and equipment, net $ 47,653 $ 43,506 Current portion of finance lease obligations $ 20,627 $ 17,455 Finance lease long-term obligations 34,181 31,522 Total finance lease liabilities $ 54,808 $ 48,977
Supplemental Cash Flow Information	Supplemental cash flow information related to leases was as follows for the year ended December 31 (in thousands): 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ (59,863 ) $ (60,361 ) Operating cash flows for finance leases (605 ) (944 ) Financing cash flows for finance leases (15,774 ) (16,434 ) Right-of-use assets obtained in exchange for lease obligations: Operating leases $ 43,385 $ 47,415 Finance leases 28,994 20,203 Lease obligations closed out in exchange for right-of-use assets: Operating leases $ (10,122 ) $ (2,834 )
Supplemental Cash Flow Information, Weighted Average	Weighted average remaining lease term as of December 31: 2021 2020 Operating leases 6 years 7 years Finance leases 3 years 3 years Weighted average discount rate as of December 31: 2021 2020 Operating leases 4.7 % 4.8 % Finance leases 1.1 % 1.3 %
Schedule of Lessee, Operating Lease, Liability, Maturity	As of December 31, 2021, maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Total 2022 $ 53,612 $ 21,443 $ 75,055 2023 53,033 17,768 70,801 2024 44,428 11,624 56,052 2025 38,036 5,688 43,724 2026 29,128 130 29,258 2027 and thereafter 73,262 — 73,262 Total lease payments 291,499 56,653 $ 348,152 Less: Management fee — (762 ) Less: Imputed interest (42,643 ) (1,083 ) Total lease liabilities $ 248,856 $ 54,808
Schedule of Finance Lease, Liability, Maturity	As of December 31, 2021, maturities of lease liabilities were as follows (in thousands): Operating Leases Finance Leases Total 2022 $ 53,612 $ 21,443 $ 75,055 2023 53,033 17,768 70,801 2024 44,428 11,624 56,052 2025 38,036 5,688 43,724 2026 29,128 130 29,258 2027 and thereafter 73,262 — 73,262 Total lease payments 291,499 56,653 $ 348,152 Less: Management fee — (762 ) Less: Imputed interest (42,643 ) (1,083 ) Total lease liabilities $ 248,856 $ 54,808

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2021
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Interest Rate Swaps Designated as Hedging Instruments on Consolidated Balance Sheets	Fair Values The fair values of the Company’s derivative financial instruments as of December 31 and the line items on the accompanying consolidated balance sheets to which they were recorded were as follows (in thousands): Balance Sheet Classification 2021 2020 Interest rate swaps - non-current Other long-term assets $ 948 $ — Fair value of derivative assets $ 948 $ — Interest rate swaps - current Accrued expenses $ 1,827 $ 17,045 Interest rate swaps - non-current Other long-term liabilities — 5,572 Fair value of derivative liabilities $ 1,827 $ 22,617

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	As of December 31, 2021, the fair values of the major classes of the Company’s assets and liabilities measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 Investments Measured at Net Asset Value Total Assets: Trading securities (a) $ 24,775 $ — $ — $ — $ 24,775 Partnership interest (b) — — — 11,176 11,176 Derivative instruments (c) — 948 — — 948 Total assets $ 24,775 $ 948 $ — $ 11,176 $ 36,899 Liabilities: Derivative instruments (c) $ — $ 1,827 $ — $ — $ 1,827 Contingent obligations related to acquisitions (d) — — 17,997 — 17,997 Total liabilities $ — $ 1,827 $ 17,997 $ — $ 19,824 As of December 31, 2020, the fair value of the major classes of the Company’s assets and liabilities measured at fair value on a recurring basis were as follows (in thousands): Level 1 Level 2 Level 3 Investments Measured at Net Asset Value Total Assets: Trading securities (a) $ 22,950 $ — $ — $ — $ 22,950 Partnership interest (b) — — — 8,665 8,665 Total assets $ 22,950 $ — $ — $ 8,665 $ 31,615 Liabilities: Derivative instruments (c) $ — $ 22,617 $ — $ — $ 22,617 Contingent obligations related to acquisitions (d) — — 6,793 — 6,793 Total liabilities $ — $ 22,617 $ 6,793 $ — $ 29,410 (a) Represents the fair value of investments in mutual funds based on quoted market prices that are used to fund the liability associated with the Company’s deferred compensation plan. (b) The Company has committed to invest $21.5 million as a limited partner in two private equity funds. The private equity funds invest in opportunities in the healthcare and life sciences industry. As of December 31, 2021, the Company’s remaining unfunded commitment in the private equity funds was $12.8 million. The Company holds minor ownership interests (less than 3%) in each of the private equity funds and has determined that it does not exercise significant influence over the private equity funds’ operating or finance activities. As the private equity funds do not have readily determinable fair values, the Company has estimated the fair values using each fund’s Net Asset Value, the amount by which the value of all assets exceeds all debt and liabilities, in accordance with ASC Topic 946 , Financial Services – Investment Companies. (c) Represents the fair value of interest rate swap arrangements (see “ – ” (d) Represents the fair value of contingent consideration obligations related to acquisitions. The fair values of these liabilities are determined based on the Company’s best estimate of the probable timing and amount of settlement.
Reconciliation of Changes in the Carrying Amount of Contingent Consideration	The following table presents a reconciliation of changes in the carrying amount of contingent obligations classified as Level 3 for the years ended December 31, 2021 and 2020 (in thousands): Balance as of December 31, 2019 $ 37,324 Additions — Changes in fair value recognized in earnings (a) (3,897 ) Payments (26,634 ) Balance as of December 31, 2020 6,793 Additions (b) 19,158 Changes in fair value recognized in earnings (757 ) Payments (c) (7,197 ) Balance as of December 31, 2021 $ 17,997 (a) The change in fair value recognized in earnings for the year ended December 31, 2020 is primarily due to a decrease in the estimate of the contingent consideration associated with the acquisition of Kinapse (see “ ” (b) Represents obligations in connection with the acquisition of RxDataScience and insignificant acquisitions completed during 2021. ( c ) The Company made payments to fully settle the contingent tax-sharing obligation arising from inVentiv Health, Inc.’s 2016 merger with Double Eagle Parent, Inc. (see “Note 1 7 – Commitments and Contingencies” for further information) during the first quarter of 2021 and obligations in connection with the insignificant acquisition completed during the second quarter of 2021 .
Schedule of Estimated Fair Value	The estimated fair values of the Company’s term loans and the Notes were as follows (in thousands): December 31, 2021 December 31, 2020 Carrying Value (a) Estimated Fair Value Carrying Value (a) Estimated Fair Value Term Loan A - tranche one due March 2024 $ 149,008 $ 148,945 $ 183,320 $ 183,026 Term Loan A - tranche two due August 2024 1,634,756 1,635,138 1,271,255 1,269,213 Term Loan B due August 2024 — — 560,194 560,144 Senior notes due January 2029 600,000 595,500 600,000 602,412

Restructuring and Other Costs (

Restructuring and Other Costs (Tables)	12 Months Ended
	Dec. 31, 2021
Restructuring And Related Activities [Abstract]
Schedule of Restructuring and Related Costs	Restructuring and other costs consisted of the following (in thousands): Year Ended December 31, 2021 2020 2019 Employee severance and benefit costs $ 14,526 $ 26,321 $ 25,243 Facility and lease termination costs 8,226 2,313 16,202 Other costs 64 780 690 Total restructuring and other costs $ 22,816 $ 29,414 $ 42,135 The following table summarizes activity related to the liabilities associated with restructuring and other costs (in thousands): Employee Severance Costs Other Costs Total Balance as of December 31, 2019 $ 5,728 $ 22 $ 5,750 Expenses incurred (a) 26,321 791 27,112 Payments (26,219 ) (813 ) (27,032 ) Balance as of December 31, 2020 5,830 — 5,830 Expenses incurred (a) 14,574 17 14,591 Payments (13,747 ) (17 ) (13,764 ) Balance as of December 31, 2021 $ 6,657 $ — $ 6,657 (a) There were no non-cash restructuring and other expenses incurred for the years ended December 31, 2021 and 2020. The amount of expenses incurred for the years ended December 31, 2021 and 2020 excludes $8.2 million and $2.3 million, respectively, of facility lease closure and lease termination costs that are reflected as a reduction of operating lease right-of-use assets on the accompanying consolidated balance sheets under ASC 842.

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2021
Equity [Abstract]
Shares of Common Stock Outstanding	Shares of common stock outstanding were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Common stock shares, beginning balance 103,935 103,866 103,372 Repurchases of common stock (1,500 ) (1,256 ) (1,323 ) Issuances of common stock 1,329 1,325 1,817 Common stock shares, ending balance 103,764 103,935 103,866
Schedule of Repurchase Activity	The following table sets forth repurchase activity under the Company’s stock repurchase programs from inception through December 31, 2021: Total number of shares purchased Average price paid per share Approximate dollar value of shares purchased (in thousands) March 2018 948,100 $ 39.55 $ 37,493 April 2018 1,024,400 36.60 37,492 January 2019 552,100 39.16 21,623 February 2019 120,600 41.40 4,993 June 2019 509,100 45.29 23,055 August 2019 141,100 49.93 7,045 March 2020 600,000 53.38 32,029 September 2020 506,244 59.26 30,000 October 2020 150,000 54.14 8,122 March 2021 600,000 74.18 44,505 May 2021 400,000 81.04 32,416 June 2021 500,000 81.20 40,600 Total 6,051,644 $ 319,373
Schedule of Stock by Class	The following is a summary of the Company’s authorized, issued, and outstanding shares as of December 31: 2021 2020 Shares Authorized: Class A common stock 300,000,000 300,000,000 Class B common stock 300,000,000 300,000,000 Preferred stock 30,000,000 30,000,000 Total shares authorized 630,000,000 630,000,000 Shares Issued and Outstanding: Class A common stock 103,763,635 103,934,738 Class B common stock — — Preferred stock — — Total shares issued and outstanding 103,763,635 103,934,738

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table provides a reconciliation of the numerators and denominators of the basic and diluted earnings per share computations (in thousands, except per share data): Year Ended December 31, 2021 2020 2019 Numerator: Net income $ 234,831 $ 192,787 $ 131,258 Denominator: Basic weighted average common shares outstanding 103,872 104,168 103,618 Effect of dilutive securities: Stock options and other awards under deferred share-based compensation programs 1,193 1,297 1,387 Diluted weighted average common shares outstanding 105,065 105,465 105,005 Earnings per share: Basic $ 2.26 $ 1.85 $ 1.27 Diluted $ 2.24 $ 1.83 $ 1.25

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Components of Income before Provision for Income Taxes	The components of income before provision for income taxes were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Domestic $ 186,445 $ 122,659 $ (17,066 ) Foreign 128,715 80,999 118,775 Income before provision for income taxes $ 315,160 $ 203,658 $ 101,709
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense (benefit) were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Federal income taxes: Current $ 926 $ (15,537 ) $ (13,952 ) Deferred 45,819 10,188 (11,693 ) Foreign income taxes: Current 27,718 16,019 21,452 Deferred (4,309 ) (3,106 ) (2,206 ) State income taxes: Current 5,163 14,229 2,850 Deferred 5,012 (10,922 ) (26,000 ) Income tax expense (benefit) $ 80,329 $ 10,871 $ (29,549 )
Schedule of Effective Income Tax Rate Reconciliation	Actual income tax expense differed from the amount computed by applying the U.S. federal tax rate of 21% to pre-tax income as a result of the following (in thousands): Year Ended December 31, 2021 2020 2019 Expected income tax expense at statutory rate $ 66,184 $ 42,768 $ 21,359 Change in income tax expense resulting from: Foreign income inclusion 11,019 6,013 39,557 Foreign earnings not indefinitely reinvested 278 5,071 — Foreign tax credits (4,390 ) — — Changes in income tax valuation allowance (all jurisdictions) (1,462 ) 14,503 (68,537 ) Change in fair value of contingent obligations (122 ) (769 ) 3,625 Share-based compensation (5,662 ) (2,800 ) 1,094 Research and general business tax credits (a) (8,902 ) (12,872 ) (1,871 ) State and local taxes, net of federal benefit 11,978 6,924 (9,085 ) Capital loss carryforward (b) (214 ) (16,506 ) — Foreign rate differential 2,865 (1,777 ) (3,595 ) Changes in reserve for uncertain tax positions including interest 4,721 (18,839 ) 5,393 Provision to tax return and other deferred tax adjustments (771 ) (12,325 ) (6,950 ) Gain on sale of business — (2,350 ) — Base erosion and anti-abuse tax — — (15,054 ) Nondeductible executive compensation 1,649 367 1,802 Other, net 3,158 3,463 2,713 Income tax expense (benefit) $ 80,329 $ 10,871 $ (29,549 ) (a) Year ended December 31, 2021 included a $0.8 million valuation allowance release and year ended December 31, 2020 was offset by a $9.4 million valuation allowance. (b) Years ended December 31, 2021 and 2020 are offset by $0.2 million and $16.5 million, respectively, in valuation allowances.
Summary of Valuation Allowance	The changes in the valuation allowance for deferred tax assets were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Balance at the beginning of the period $ 100,310 $ 84,159 $ 150,316 Deferred tax assets assumed through acquisitions — 479 — Deferred tax assets released through divestitures — (271 ) — (Credited) charged to income tax expense (1,462 ) 14,503 (68,537 ) Charged to equity — — 42 Foreign currency exchange (407 ) 1,440 2,338 Other adjustments (479 ) — — Balance at the end of the period $ 97,962 $ 100,310 $ 84,159
Schedule of Deferred Tax Assets and Liabilities	The income tax effects of temporary differences that give rise to significant portions of the deferred tax assets and liabilities are as follows as of December 31 (in thousands): 2021 2020 Deferred tax assets: Net operating losses $ 134,143 $ 122,018 Tax credits 58,901 58,603 Deferred revenue — 77,138 Employee compensation and other benefits 28,538 29,048 Allowance for doubtful accounts 1,787 1,739 Lease obligations 57,749 57,142 Accrued expenses 13,158 6,526 Prepaid royalty — 3,451 Capital loss carryforward 20,021 20,157 Interest limitation carryforwards 30,847 20,219 Other 1,151 7,913 Total deferred tax assets 346,295 403,954 Less: valuation allowance (97,962 ) (100,310 ) Net deferred tax assets 248,333 303,644 Deferred tax liabilities: Undistributed foreign earnings (7,778 ) (10,912 ) Right of use asset (47,532 ) (49,316 ) Depreciation and amortization (214,636 ) (226,170 ) Deferred revenue (17,247 ) — Other (3,814 ) (2,404 ) Total deferred tax liabilities (291,007 ) (288,802 ) Net deferred tax assets $ (42,674 ) $ 14,842
Schedule Of Unrecognized Tax Benefits	A reconciliation of the beginning and ending balances of unrecognized tax benefits, excluding accrued interest and penalties, is as follows (in thousands): Unrecognized tax benefits balance as of December 31, 2018 $ 19,245 Increases for tax positions in the current year 2,222 Increases for tax positions of prior years 2,255 Decreases for tax positions in prior year (440 ) Impact of foreign currency translation (44 ) Unrecognized tax benefits balance as of December 31, 2019 23,238 Increases for tax positions in the current year 254 Increases for tax positions of prior years 3,237 Decreases for tax positions in prior year (2,540 ) Impact of foreign currency translation 132 Lapse of statute limitations (15,288 ) Unrecognized tax benefits balance as of December 31, 2020 9,033 Increases for tax positions in the current year 386 Increases for tax positions of prior years 4,233 Settlements with tax authorities (1,131 ) Impact of foreign currency translation (169 ) Lapse of statute limitations (234 ) Unrecognized tax benefits balance as of December 31, 2021 $ 12,118

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of Segment Information	Information about reportable segment operating results was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Revenue: Clinical Solutions $ 4,009,057 $ 3,339,451 $ 3,450,223 Commercial Solutions 1,203,913 1,076,326 1,225,592 Total revenue 5,212,970 4,415,777 4,675,815 Segment direct costs: Clinical Solutions 3,005,938 2,513,240 2,637,016 Commercial Solutions 955,326 853,555 979,878 Total segment direct costs 3,961,264 3,366,795 3,616,894 Segment selling, general, and administrative expenses: Clinical Solutions 353,990 283,633 280,674 Commercial Solutions 82,516 82,709 87,258 Total segment selling, general, and administrative expenses 436,506 366,342 367,932 Segment operating income: Clinical Solutions 649,129 542,578 532,533 Commercial Solutions 166,071 140,062 158,456 Total segment operating income 815,200 682,640 690,989 Direct costs and operating expenses not allocated to segments: Share-based compensation included in direct costs 33,220 31,347 29,011 Share-based compensation included in selling, general, and administrative expenses 31,984 27,144 26,182 Corporate selling, general, and administrative expenses 102,275 79,240 113,442 Restructuring and other costs 22,816 29,414 42,135 Depreciation and amortization 235,625 222,352 242,465 Total income from operations $ 389,280 $ 293,143 $ 237,754

Operations by Geographic Loca_2

Operations by Geographic Location (Tables)	12 Months Ended
	Dec. 31, 2021
Segments Geographical Areas [Abstract]
Total Revenue by Geographic Area	The following table summarizes total revenue by geographic area (in thousands, all intercompany transactions have been eliminated): Year Ended December 31, 2021 2020 2019 Revenue: North America (a) $ 3,144,475 $ 2,791,590 $ 3,079,608 Europe, Middle East and Africa 1,333,540 1,059,968 1,055,007 Asia-Pacific 594,163 465,116 444,819 Latin America 140,792 99,103 96,381 Total revenue $ 5,212,970 $ 4,415,777 $ 4,675,815 (a) Revenue for the North America region includes revenue attributable to the U.S. of $2.95 billion, $2.64 billion, and $2.93 billion, or 56.6%, 59.9%, and 62.7% of total revenue, for the years ended December 31, 2021, 2020 and 2019, respectively. No other country represented more than 10% of total revenue for any year.
Long-Lived Assets by Geographic Area	The following table summarizes long-lived assets by geographic area as of December 31 (in thousands, all intercompany transactions have been eliminated): 2021 2020 Property and equipment, net: North America (a) $ 165,446 $ 161,531 Europe, Middle East and Africa 37,004 38,745 Asia-Pacific 13,615 11,167 Latin America 6,592 4,757 Total property and equipment, net $ 222,657 $ 216,200

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Option Valuation Assumptions	The fair values of ESPP offerings were determined using the Black-Scholes valuation model and the following assumptions: Year Ended December 31, 2021 2020 2019 Expected volatility 25.3% - 38.3% 27.7% - 55.1% 39.1% - 51.9% Risk-free interest rate 0.06% - 0.07% 0.13% - 0.95% 1.88% - 2.52% Expected term (in years) 0.5 0.5 0.5
Summary of Stock Option Activity	The following table sets forth the summary of stock option activity for the year ended December 31, 2021: Number of Options Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands)(a) Outstanding as of December 31, 2020 663,559 $ 30.12 Exercised (279,072 ) 33.31 Forfeited — — Outstanding as of December 31, 2021 384,487 27.81 3.26 $ 28,787 Vested and expected to vest as of December 31, 2021 384,487 27.81 3.26 $ 28,787 Exercisable as of December 31, 2021 384,487 27.81 3.26 $ 28,787 (a) Represents the total pre-tax intrinsic value (i.e., the aggregate difference between the closing price of the Company’s common stock on December 31, 2021 of $102.68 and the exercise price for in-the-money options) that would have been received by the holders if all instruments had been exercised on December 31, 2021.
Summary of Restricted Stock Unit Activity	The following table sets forth a summary of RSUs outstanding under the 2014 and 2018 Plans as of December 31, 2021 and changes during the year then ended: Time-based Performance-based Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Total Number of Shares Non-vested as of December 31, 2020 1,909,882 $ 51.98 461,499 $ 48.99 2,371,381 Granted 939,031 76.96 59,055 75.43 998,086 Vested (997,632 ) 48.45 (136,665 ) 46.47 (1,134,297 ) Forfeited (226,094 ) 64.07 (27,890 ) 58.71 (253,984 ) Non-vested as of December 31, 2021 1,625,187 $ 66.90 355,999 $ 60.75 1,981,186 Unrecognized compensation expense (in millions) $ 62.6 $ 10.7 Weighted average period unrecognized compensation is expected to be recognized 1.9 years 1.9 years
Summary of Share-Based Compensation Expense	Total share-based compensation expense recognized was as follows (in thousands): Year Ended December 31, 2021 2020 2019 Direct costs $ 33,220 $ 31,347 $ 29,011 Selling, general, and administrative expenses 31,984 27,144 26,182 Total share-based compensation expense $ 65,204 $ 58,491 $ 55,193

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Schedule of Contributions to Defined Contribution Plan	The Company’s contributions related to these defined contribution retirement plans were as follows (in thousands): Year Ended December 31, 2021 2020 2019 Defined contribution retirement plan contributions $ 30,932 $ 15,049 $ 29,834

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)	Jan. 01, 2020USD ($)	Dec. 31, 2021USD ($)Segmentreportingunit	Dec. 31, 2020USD ($)	Dec. 31, 2021USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Number of reportable segments | Segment		2
Restricted cash		$ 100,000	$ 300,000	$ 100,000
Number of reporting units with goodwill assigned | reportingunit		4
Impairment of goodwill				$ 0
Impact from adoption of ASU			(2,771,000)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2016-13
Impact from adoption of ASU	$ 2,800,000
Change in accounting principle, accounting standards update, adopted [true/false]		true		true
Change in accounting principle, accounting standards update, adoption date		Jan. 1, 2020		Jan. 1, 2020
Minimum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Contract Termination Notice Period		30 days
Maximum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Contract Termination Notice Period		90 days
Inventiv
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Impairment charge		$ 0	$ 0
Computer equipment and software
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Property and equipment, estimated useful life		5 years
Computer equipment and software | Minimum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Property and equipment, estimated useful life		2 years
Computer equipment and software | Maximum
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Property and equipment, estimated useful life		3 years

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Net Cash Pool Position (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Gross cash position	$ 179,160	$ 220,261
Less: cash borrowings	(167,507)	(204,647)
Net cash position	$ 11,653	$ 15,614

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Estimated Useful Lives of Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2021
Buildings
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	39 years
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	7 years
Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	10 years
Computer equipment and software
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Computer equipment and software | Minimum
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	2 years
Computer equipment and software | Maximum
Property Plant And Equipment [Line Items]
Property and equipment, estimated useful life	3 years

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Estimated Useful Lives of Intangible Assets (Details) - Weighted Average	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Customer relationships
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	9 years 9 months 18 days	9 years 10 months 24 days
Acquired backlog
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	2 years 7 months 6 days	2 years 7 months 6 days
Trade names and trademarks
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	5 years 6 months	5 years 6 months
Intellectual property (medical patent)
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life		9 years
Patient Communities
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	6 years
Acquired Technology
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	6 years

Financial Statement Details - A

Financial Statement Details - Accounts Receivable and Unbilled Services, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Accounts receivable billed	$ 873,265	$ 774,605
Accounts receivable unbilled	241,799	211,285
Contract assets	417,411	366,506
Less: Allowance for doubtful accounts	(7,585)	(7,615)
Accounts receivable and unbilled services, net	1,524,890	1,344,781
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at the beginning of the period	(7,615)	(5,381)	$ (4,587)
Impact from adoption of ASU		(2,771)
Current year provision	(367)	(695)	(1,897)
Write-offs, net of recoveries and the effects of foreign currency exchange	397	1,232	1,103
Balance at the end of the period	$ (7,585)	$ (7,615)	$ (5,381)

Financial Statement Details - N

Financial Statement Details - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Trade receivables sold	$ 129,100	$ 152,400
Proceeds from sale of trade receivables	128,900	151,900
Property and equipment, gross	77,674	63,985
Amortization charges, net of rebates	47,653	43,506
Vehicles
Property Plant And Equipment [Line Items]
Property and equipment, gross	77,700	64,000
Accumulated depreciation	30,000	20,500
Amortization charges, net of rebates	$ 17,500	$ 15,800

Financial Statement Details - S

Financial Statement Details - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 524,951	$ 467,169
Less: Accumulated depreciation	(302,294)	(250,969)
Property and equipment, net	222,657	216,200
Software
Property Plant And Equipment [Line Items]
Property and equipment, gross	159,736	129,731
Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	96,188	94,596
Computer equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	91,937	108,230
Vehicles
Property Plant And Equipment [Line Items]
Property and equipment, gross	77,674	63,985
Furniture and fixtures
Property Plant And Equipment [Line Items]
Property and equipment, gross	65,018	37,287
Buildings and land
Property Plant And Equipment [Line Items]
Property and equipment, gross	5,692	5,211
Assets not yet placed in service
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 28,706	$ 28,129

Financial Statement Details -_2

Financial Statement Details - Schedule of Goodwill (Details) - USD ($)	12 Months Ended			39 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2021
Goodwill [Roll Forward]
Balance as of December 31, 2019	$ 4,776,178,000	$ 4,350,380,000
Acquisitions	192,286,000	404,166,000
Impact of foreign currency translation and other	(12,449,000)	21,632,000
Balance as of December 31, 2020	4,956,015,000	4,776,178,000	$ 4,350,380,000	$ 4,956,015,000
Impairment of goodwill				0
Clinical Solutions
Goodwill [Roll Forward]
Balance as of December 31, 2019	3,216,335,000	2,784,952,000
Acquisitions	192,286,000	418,619,000
Impact of foreign currency translation and other	40,078,000	12,764,000
Balance as of December 31, 2020	3,448,699,000	3,216,335,000	2,784,952,000	3,448,699,000
Accumulated impairment loss	8,100,000	8,100,000	8,100,000	8,100,000
Impairment of goodwill	0	0	0
Transfer of goodwill	44,200,000
Commercial Solutions
Goodwill [Roll Forward]
Balance as of December 31, 2019	1,559,843,000	1,565,428,000
Acquisitions		(14,453,000)
Impact of foreign currency translation and other	(52,527,000)	8,868,000
Balance as of December 31, 2020	1,507,316,000	1,559,843,000	1,565,428,000	1,507,316,000
Accumulated impairment loss	8,000,000	8,000,000	8,000,000	$ 8,000,000
Impairment of goodwill	$ 0	$ 0	$ 0

Financial Statement Details -_3

Financial Statement Details - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	$ 1,852,379	$ 1,774,764
Accumulated amortization	(998,312)	(841,239)
Finite-lived intangible assets, net	854,067	933,525
Customer relationships
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	1,547,925	1,518,081
Accumulated amortization	(811,542)	(685,021)
Finite-lived intangible assets, net	736,383	833,060
Backlog
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	175,826	174,180
Accumulated amortization	(154,475)	(132,733)
Finite-lived intangible assets, net	21,351	41,447
Trade names and trademarks
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	55,728	52,475
Accumulated amortization	(28,806)	(21,817)
Finite-lived intangible assets, net	26,922	30,658
Intellectual property (medical patent)
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		30,028
Accumulated amortization		(1,668)
Finite-lived intangible assets, net		$ 28,360
Patient communities
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	45,100
Accumulated amortization	(2,192)
Finite-lived intangible assets, net	42,908
Acquired Technology
Finite Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	27,800
Accumulated amortization	(1,297)
Finite-lived intangible assets, net	$ 26,503

Financial Statement Details -_4

Financial Statement Details - Schedule of Future Amortization Expense (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
2022	$ 162,193
2023	153,334
2024	146,487
2025	132,512
2026	110,597
2027 and thereafter	148,944
Finite-lived intangible assets, net	$ 854,067	$ 933,525

Financial Statement Details -_5

Financial Statement Details - Schedule of Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Professional fees, investigator fees, and pass-through costs	$ 283,432	$ 231,638
Compensation, including bonuses, fringe benefits, and payroll taxes	215,386	255,042
Income and other taxes	25,723	28,890
Rebates to customers	22,367	22,528
Restructuring and other costs, current portion	6,657	5,830
Contingent obligations, current	3,397	4,327
Interest rate swaps - current	1,827	17,045
Other liabilities	55,652	45,742
Total accrued expenses	$ 614,441	$ 611,042

Financial Statement Details -_6

Financial Statement Details - Accumulated Other Comprehensive Loss, Net of Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 3,242,112	$ 3,029,654	$ 2,856,144
Other comprehensive gain (loss) before reclassifications	2,963	(20,446)
Balance at end of period	3,412,555	3,242,112	3,029,654
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(40,801)	(71,593)	(88,195)
Balance at end of period	(49,618)	(40,801)	(71,593)
Foreign Currency Translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(22,040)	(56,757)
Other comprehensive gain (loss) before reclassifications	(24,957)	34,717	24,198
Balance at end of period	(46,997)	(22,040)	(56,757)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(18,761)	(14,836)
Other comprehensive gain (loss) before reclassifications	2,963	(20,446)	(11,529)
Reclassification adjustments	13,177	16,521	3,933
Balance at end of period	$ (2,621)	$ (18,761)	$ (14,836)

Financial Statement Details - T

Financial Statement Details - Tax Effects Allocated to Each Component of Other Comprehensive (Loss) Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income Loss [Line Items]
Unrealized gain (loss) during period, before taxes	$ 4,084	$ (27,647)	$ (14,306)
Other comprehensive gain (loss) before reclassifications	2,963	(20,446)
Income tax (benefit) expense	1,472	(1,354)	0
Other comprehensive income before reclassifications	2,963	(20,446)
Foreign Currency Translation
Accumulated Other Comprehensive Income Loss [Line Items]
Income tax expense (benefit)	(26,429)	36,071	24,198
Other comprehensive gain (loss) before reclassifications	(24,957)	34,717	24,198
Total unrealized gain (loss) on derivative instruments, net of taxes	(8,817)	30,792	16,602
Income tax (benefit) expense	(1,472)	1,354
Other comprehensive income before reclassifications	(24,957)	34,717	24,198
Derivative Instruments
Accumulated Other Comprehensive Income Loss [Line Items]
Income tax expense (benefit)	1,121	(7,201)	(2,777)
Other comprehensive gain (loss) before reclassifications	2,963	(20,446)	(11,529)
Reclassification adjustment, before taxes	17,655	22,328	4,588
Income tax expense	4,478	5,807	655
Reclassification adjustment, net of taxes	13,177	16,521	3,933
Total unrealized gain (loss) on derivative instruments, net of taxes	16,140	(3,925)	(7,596)
Other comprehensive income before reclassifications	$ 2,963	$ (20,446)	$ (11,529)

Financial Statement Details -_7

Financial Statement Details - Schedule of Other (Income) Expense, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Net realized foreign currency loss	$ 2,190	$ 3,175	$ 11,853
Net unrealized foreign currency (gain) loss	(5,928)	4,147	11,166
Gain on sale of business		(7,133)
Equity investment (income) expense	(1,950)	(3,745)	261
Other, net	(2,945)	580	882
Total other (income) expense, net	$ (8,633)	$ (2,976)	$ 24,162

Financial Statement Details -_8

Financial Statement Details - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Cash paid for income taxes, net of refunds		$ 35,100	$ 23,400	$ 12,200
Cash paid for interest (excluding finance leases)		63,952	83,690	129,756
Supplemental disclosure of noncash investing and financing activities
Non-cash investment to acquire certain intellectual property rights from a customer in lieu of cash payment for services rendered	$ 27,300		27,300
Fair value of contingent consideration related to acquisitions		19,158
Change in property and equipment included in liabilities		1,753	11,684	5,977
Vehicles acquired through finance lease agreements		$ 28,994	$ 20,203	$ 37,701

Acquisitions, Divestitures, a_3

Acquisitions, Divestitures, and Investments - Narrative (Details) - USD ($)	Oct. 06, 2021	Sep. 13, 2021	Dec. 17, 2020	Dec. 09, 2020	Sep. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill							$ 4,776,178,000		$ 4,956,015,000	$ 4,776,178,000	$ 4,350,380,000
Business acquisition payment of cash									278,920,000	456,455,000	712,000
Contingent consideration							1,800,000			1,800,000
Gain (loss) on divestiture										7,133,000
Non-cash investment to acquire certain intellectual property rights from a customer in lieu of cash payment for services rendered								$ 27,300,000		27,300,000
Assets Exchanged In Cash					$ 3,800,000
Income (Loss) from Equity Method Investments									5,300,000
Other long-term investments									16,200
Maximum loss on investment for a VIE									20,300
Clinical Solutions
Business Acquisition [Line Items]
Goodwill							3,216,335,000		3,448,699,000	3,216,335,000	$ 2,784,952,000
Cash consideration							18,000,000
Contingent consideration							3,600,000		$ 3,000,000	3,600,000
Divestiture, consideration received							23,000,000			$ 23,000,000
Convertible notes							5,000,000
Proceeds from notes receivable							5,000,000
Gain (loss) on divestiture							$ 7,100,000
Related Party
Business Acquisition [Line Items]
Contingent consideration								1,800
Related Party | Maximum
Business Acquisition [Line Items]
Cash consideration								$ 4,000,000
StudyKIK Acquisition [Member]
Business Acquisition [Line Items]
Name of acquired entity		StudyKIK
Date of Acquisition		Sep. 13, 2021
Aggregate purchase price for the acquisition		$ 203,600
Cash acquired		1,000
Goodwill		115,300
Intangible assets		$ 91,800
Rx Data Science Acquisitions
Business Acquisition [Line Items]
Name of acquired entity	RxDataScience
Date of Acquisition	Oct. 6, 2021
Aggregate purchase price for the acquisition	$ 67,500,000
Cash acquired	2,400,000
Goodwill	52,900,000
Intangible assets	$ 18,000,000
Synteract Acquisition [Member]
Business Acquisition [Line Items]
Name of acquired entity				Synteract
Date of Acquisition				Dec. 9, 2020
Aggregate purchase price for the acquisition				$ 385,500,000
Cash acquired				28,000,000
Goodwill				363,733,000
Intangible assets				$ 56,400,000
Percentage of Outstanding Shares Purchase				100.00%
Business acquisition payment of cash						$ 1,000,000
Illingworth Research Group Acquisition
Business Acquisition [Line Items]
Date of Acquisition			Dec. 17, 2020
Aggregate purchase price for the acquisition			$ 80,900,000
Cash acquired			1,100,000
Goodwill			64,600,000
Intangible assets			$ 21,500,000
Business acquisition payment of cash						$ 9,000,000

Acquisitions, Divestitures, a_4

Acquisitions, Divestitures, and Investments - Preliminary Estimates of Fair Values of Intangible Assets and Estimated Useful Lives (Details) - StudyKIK Acquisition [Member] $ in Thousands	Sep. 13, 2021USD ($)
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 91,800
Customer relationships
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 22,300
Estimated Useful Life	6 years
Acquired backlog
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 1,800
Estimated Useful Life	1 year 3 months
Trade name
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 2,700
Estimated Useful Life	6 years
Patient Communities
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 45,100
Estimated Useful Life	6 years
Acquired Technology
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 19,900
Estimated Useful Life	6 years

Acquisitions, Divestitures, a_5

Acquisitions, Divestitures, and Investments - Allocation of Consideration Transferred (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 09, 2020	Dec. 31, 2019
Assets acquired:
Goodwill	$ 4,956,015	$ 4,776,178		$ 4,350,380
Synteract Acquisition [Member]
Assets acquired:
Cash and cash equivalents			$ 28,028
Accounts receivable and unbilled services			39,723
Prepaid expenses and other current assets			2,160
Property and equipment			3,978
Operating lease right-of-use assets			10,839
Other identifiable intangible assets			56,400
Goodwill			363,733
Other assets			4,121
Total assets acquired			508,982
Liabilities assumed:
Accounts payable and accrued expenses			25,623
Deferred revenue			45,272
Operating lease obligations			15,693
Deferred income taxes, net			7,754
Other liabilities			1,126
Total liabilities assumed			95,468
Net assets acquired			$ 413,514

Acquisitions, Divestitures, a_6

Acquisitions, Divestitures, and Investments - Preliminary Estimates of Fair Value of Intangible Assets and Estimated Useful Lives (Details) - Synteract Acquisition [Member] $ in Thousands	Dec. 09, 2020USD ($)
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 56,400
Acquired backlog
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 37,200
Acquired backlog | Maximum
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	4 years
Trade name
Finite Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 19,200
Trade name | Maximum
Finite Lived Intangible Assets [Line Items]
Estimated Useful Life	8 years

Long-Term Debt Obligations - Sc

Long-Term Debt Obligations - Schedule of Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Less: Term loans original issuance discount	$ (2,228)	$ (3,500)
Less: Unamortized deferred issuance costs	(8,043)	(12,716)
Long-term debt	2,775,721	2,902,054
Secured Debt
Debt Instrument [Line Items]
Total debt obligations	2,185,992	2,318,270
Secured Debt | Term Loan A - tranche one due March 2024
Debt Instrument [Line Items]
Total debt obligations	149,195	183,715
Secured Debt | Term Loan A - tranche two due August 2024
Debt Instrument [Line Items]
Total debt obligations	1,636,797	1,273,991
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024
Debt Instrument [Line Items]
Total debt obligations		560,564
Secured Debt | Accounts receivable financing agreement due October 2022 | Accounts Receivable Securitization
Debt Instrument [Line Items]
Total debt obligations	400,000	300,000
Unsecured Debt
Debt Instrument [Line Items]
Total debt obligations	2,785,992	2,918,270
Unsecured Debt | Senior Unsecured Notes due January 2029
Debt Instrument [Line Items]
Total debt obligations	$ 600,000	$ 600,000

Long-Term Debt Obligations - Na

Long-Term Debt Obligations - Narrative (Details)	Feb. 28, 2021	Aug. 01, 2017	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Nov. 24, 2020USD ($)
Debt Instrument [Line Items]
Repayments of Long-term debt			$ 727,277,000	$ 327,294,000	$ 437,936,000
Loss on extinguishment of debt			(3,612,000)	(1,581,000)	10,395,000
Proceeds from issuance of long-term debt, net of discount			$ 494,505,000	600,000,000	$ 582,000,000
Senior Unsecured Notes Due2029
Debt Instrument [Line Items]
Percentage redeemed			40.00%
Debt redemption price percentage			103.625%
Secured Debt
Debt Instrument [Line Items]
Loss on extinguishment of debt			$ 3,600,000
Secured Debt | Letter of credit
Debt Instrument [Line Items]
Line of credit facility, capacity available for trade purchases			135,800,000
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due March 2024
Debt Instrument [Line Items]
Repayments of Long-term debt			166,800,000
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due March 2024 | Term Loan
Debt Instrument [Line Items]
Term loan facility			1,550,000,000
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024
Debt Instrument [Line Items]
Repayments of Long-term debt			560,500,000
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Term Loan
Debt Instrument [Line Items]
Term loan facility			1,600,000,000
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Revolving credit facility due August 2024
Debt Instrument [Line Items]
Maximum borrowing capacity under accounts receivable financing agreement			600,000,000
Secured Debt | Credit Agreement Amendment No5 Term Loan A | Term Loan
Debt Instrument [Line Items]
Additional discount on Term loan			500,000
Secured Debt | Credit Agreement Amendment No5 Term Loan A | Incremental Term Loan
Debt Instrument [Line Items]
Term loan facility			$ 495,000,000
Secured Debt | 2017 Credit Agreement
Debt Instrument [Line Items]
Percentage of capital stock of certain controlled foreign subsidiaries securing debt obligation			65.00%
Secured Debt | 2017 Credit Agreement | Federal Funds Effective Rate
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)		0.50%
Secured Debt | 2017 Credit Agreement | Eurodollar Rate
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)		1.00%
Secured Debt | 2017 Credit Agreement | Base Rate
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)		0.00%
Secured Debt | 2017 Credit Agreement - Revolving Credit Facility | Revolving credit facility due August 2024
Debt Instrument [Line Items]
Interest rate			1.35%
Outstanding borrowings			$ 0
Available borrowings			$ 585,800,000
Secured Debt | 2017 Credit Agreement - Revolving Credit Facility | Revolving credit facility due August 2024 | Minimum
Debt Instrument [Line Items]
Quarterly commitment fee on average daily unused balance		0.25%
Secured Debt | 2017 Credit Agreement - Revolving Credit Facility | Revolving credit facility due August 2024 | Maximum
Debt Instrument [Line Items]
Quarterly commitment fee on average daily unused balance		0.375%
Secured Debt | 2017 Credit Agreement - Revolving Credit Facility | Revolving credit facility due August 2024 | Base Rate | Minimum
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)			0.25%
Secured Debt | 2017 Credit Agreement - Revolving Credit Facility | Revolving credit facility due August 2024 | Base Rate | Maximum
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)			0.50%
Secured Debt | 2017 Credit Agreement - Revolving Credit Facility | Letter of credit
Debt Instrument [Line Items]
Maximum borrowing capacity under accounts receivable financing agreement				150,000,000
Outstanding borrowings				$ 14,200,000
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Term Loan
Debt Instrument [Line Items]
Maximum first lien leverage ratio	0.025
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Term Loan | Minimum
Debt Instrument [Line Items]
Derivative, Basis Spread on Variable Rate	1.25%
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Term Loan | Maximum
Debt Instrument [Line Items]
Derivative, Basis Spread on Variable Rate	1.50%
3.625% Senior Notes | Senior Unsecured Notes Due2029
Debt Instrument [Line Items]
Term loan facility						$ 600,000,000
Debt instrument, interest rate			3.625%

Long-Term Debt Obligations - _2

Long-Term Debt Obligations - Schedule of Variable Rate Margins (Details) - Secured Debt	12 Months Ended
	Dec. 31, 2021
Minimum | Term Loan A | Base Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	0.25%
Minimum | Term Loan A | Eurocurrency Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	1.25%
Minimum | Term Loan B | Base Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	0.75%
Minimum | Term Loan B | Eurocurrency Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	1.75%
Minimum | 2017 Credit Agreement - Revolving Credit Facility | Base Rate | Revolving credit facility due August 2024
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	0.25%
Minimum | 2017 Credit Agreement - Revolving Credit Facility | Eurocurrency Rate | Revolving credit facility due August 2024
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	1.25%
Maximum | Term Loan A | Base Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	0.50%
Maximum | Term Loan A | Eurocurrency Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	1.50%
Maximum | Term Loan B | Base Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	1.00%
Maximum | Term Loan B | Eurocurrency Rate | Term Loan
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	2.00%
Maximum | 2017 Credit Agreement - Revolving Credit Facility | Base Rate | Revolving credit facility due August 2024
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	0.50%
Maximum | 2017 Credit Agreement - Revolving Credit Facility | Eurocurrency Rate | Revolving credit facility due August 2024
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)	1.50%

Long-Term Debt Obligations - Ac

Long-Term Debt Obligations - Accounts Receivable Financing Agreement (Details) - USD ($) $ in Thousands	Oct. 13, 2021	Jan. 28, 2021	Dec. 31, 2021	Jan. 27, 2021	Sep. 25, 2020	Sep. 24, 2020
Debt Instrument [Line Items]
Line of credit facility, decrease, forgiveness	$ 35,000	$ 65,000
Long-term debt			$ 2,775,721
Voluntary prepayments on term loans			$ 35,000
Accounts Receivable Securitization | Secured Debt | Accounts receivable financing agreement due September 2021
Debt Instrument [Line Items]
Weighted average imputed interest rate			1.05%
Subsidiaries | Accounts Receivable Securitization | Secured Debt | Accounts receivable financing agreement due October 2022
Debt Instrument [Line Items]
Maximum borrowing capacity under accounts receivable financing agreement		$ 365,000	$ 400,000	$ 300,000	$ 400,000	$ 365,000
Subsidiaries | Accounts Receivable Securitization | Secured Debt | Accounts receivable financing agreement due October 2022 | Federal Funds Rate
Debt Instrument [Line Items]
Applicable margin on variable rate (percent)			0.50%

Long-Term Debt Obligations - Co

Long-Term Debt Obligations - Contractual Maturities of Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
2023	$ 21,732
2024	2,164,260
2027 and thereafter	600,000
Less: Term loans original issuance discount	(2,228)	$ (3,500)
Less: Unamortized deferred issuance costs	(8,043)	$ (12,716)
Total	2,775,721
Senior Unsecured Notes Due2029
Debt Instrument [Line Items]
Less: Term loans original issuance discount	$ (2,228)

Leases - Narrative (Details)

Leases - Narrative (Details)	12 Months Ended
	Dec. 31, 2021
Minimum
Lessee Lease Description [Line Items]
Lease, remaining lease term	1 year
Maximum
Lessee Lease Description [Line Items]
Lease, remaining lease term	11 years

Leases - Components of Lease Co

Leases - Components of Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Fixed lease costs	$ 55,168	$ 53,531
Short-term lease costs	1,994	2,930
Variable lease costs	36,760	29,572
Total operating lease costs	93,922	86,033
Amortization of right-of-use assets	17,453	15,843
Interest on lease liabilities	605	944
Variable lease costs	6,231	6,321
Total finance lease costs	$ 24,289	$ 23,108

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Property and equipment, gross	$ 77,674	$ 63,985
Accumulated depreciation	(30,021)	(20,479)
Property and equipment, net	47,653	43,506
Current portion of finance lease obligations	20,627	17,455
Finance lease long-term obligations	34,181	31,522
Total finance lease liabilities	$ 54,808	$ 48,977

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash flows for operating leases	$ (59,863)	$ (60,361)
Operating cash flows for finance leases	(605)	(944)
Payments of finance leases	(15,774)	(16,434)	$ (14,493)
Right-of-use asset obtained in exchange for lease liability, Operating leases	43,385	47,415
Right-of-use asset obtained in exchange for lease liability, Finance leases	28,994	20,203
Lease obligations closed out in exchange for right-of-use asset, Operating leases	$ (10,122)	$ (2,834)

Leases - Supplemental Cash Fl_2

Leases - Supplemental Cash Flow Information, Weighted Average (Details)	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Weighted average remaining lease term, Operating lease	6 years	7 years
Weighted average remaining lease term, Finance lease	3 years	3 years
Weighted average discount rate, Operating leases	4.70%	4.80%
Weighted average discount rate, Finance leases	1.10%	1.30%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Operating Leases
2022	$ 53,612
2023	53,033
2024	44,428
2025	38,036
2026	29,128
2027 and thereafter	73,262
Total lease payments	291,499
Less: Imputed interest	(42,643)
Total lease liabilities	248,856
Finance Leases
2022	21,443
2023	17,768
2024	11,624
2025	5,688
2026	130
Total lease payments	56,653
Less: Management fee	(762)
Less: Imputed interest	(1,083)
Total lease liabilities	54,808	$ 48,977
2022	75,055
2023	70,801
2024	56,052
2025	43,724
2026	29,258
2027 and thereafter	73,262
Total lease payments	$ 348,152

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jun. 30, 2021	Mar. 31, 2020	Dec. 31, 2018
Derivative [Line Items]
Foreign currency forward gain loss realized	$ (2,190)	$ (3,175)	$ (11,853)
Interest Rate Swap, expiring June 30, 2021
Derivative [Line Items]
Notional amount						$ 1,010,000
Interest Rate Swap, expiring March 31, 2023
Derivative [Line Items]
Notional amount	1,160,000			$ 1,420,000	$ 549,200
Foreign Exchange Forward
Derivative [Line Items]
Notional amount	70,000
Foreign currency forward gain loss realized	$ 700	$ 1,500

Derivatives - Interest Rate Swa

Derivatives - Interest Rate Swaps Designated as Hedging Instruments on Consolidated Balance Sheets (Details) - Cash Flow Hedging - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative assets	$ 948
Derivative liability	1,827	$ 22,617
Intrest rate swaps | Other Noncurrent Assets
Derivatives, Fair Value [Line Items]
Derivative assets - non-current	948
Intrest rate swaps | Accrued expenses
Derivatives, Fair Value [Line Items]
Derivative liability - current	$ 1,827	17,045
Intrest rate swaps | Other Noncurrent Liabilities
Derivatives, Fair Value [Line Items]
Derivative assets - non-current		$ 5,572

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Liabilities:
Contingent obligations related to acquisitions	$ 3,400
Recurring
Assets:
Trading securities	24,775	$ 22,950
Total assets	36,899	31,615
Derivative liability - current	948
Liabilities:
Derivative instruments	1,827	22,617
Contingent obligations related to acquisitions	17,997	6,793
Total liabilities	19,824	29,410
Recurring | Partnership Interest
Assets:
Partnership interest	11,176	8,665
Recurring | Level 1
Assets:
Trading securities	24,775	22,950
Total assets	24,775	22,950
Recurring | Level 2
Assets:
Total assets	948
Derivative liability - current	948
Liabilities:
Derivative instruments	1,827	22,617
Total liabilities	1,827	22,617
Recurring | Level 3
Liabilities:
Contingent obligations related to acquisitions	17,997	6,793
Total liabilities	17,997	6,793
Recurring | Investments Measured at Net Asset Value
Assets:
Total assets	11,176	8,665
Recurring | Investments Measured at Net Asset Value | Partnership Interest
Assets:
Partnership interest	$ 11,176	$ 8,665

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Parenthetical) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)EquityFund
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Commitment to invest a limited partner in private equity funds	$ 21.5
Remaining unfunded commitment	$ 12.8
Number of private equity funds | EquityFund	2
Healthcare and Life Sciences Industry
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Minority interest ownership percentage	3.00%

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Changes in the Carrying Amount of Contingent Consideration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Balance at Beginning of period	$ 6,793	$ 37,324
Additions	19,158
Changes in fair value recognized in earnings	(757)	(3,897)
Payments	(7,197)	(26,634)
Balance at End of period	$ 17,997	$ 6,793

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value assets transferred from level 1 to level 2	$ 0	$ 0
Fair value assets transferred from level 2 to level 1	0	0
Fair value liabilities transferred from level 1 to level 2	0	0
Fair value liabilities transferred from level 2 to level 1	0	0
Fair value assets transferred into level 3	0	0
Fair value assets transferred out of level 3	0	0
Fair value liabilities transferred into level 3	0	0
Fair value liabilities transferred out of level 3	0	0
Nonrecurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Goodwill and identifiable intangible assets	$ 5,830,000	$ 5,710,000

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Estimated Fair Value (Details) - Level 2 - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Secured Debt | Term Loan A - Tranche One Due March 2024 | Reported Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, carrying value	$ 149,008	$ 183,320
Secured Debt | Term Loan A - Tranche One Due March 2024 | Estimate of Fair Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, fair value	148,945	183,026
Secured Debt | Term Loan A - Tranche Two Due August 2024 | Reported Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, carrying value	1,634,756	1,271,255
Secured Debt | Term Loan A - Tranche Two Due August 2024 | Estimate of Fair Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, fair value	1,635,138	1,269,213
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Reported Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, carrying value		560,194
Secured Debt | 2017 Credit Agreement - Amendment No 2 - Term Loan B Due August 2024 | Estimate of Fair Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, fair value		560,144
Unsecured Debt | Senior Notes Due January 2029 | Reported Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, carrying value	600,000	600,000
Unsecured Debt | Senior Notes Due January 2029 | Estimate of Fair Value Measurement
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term debt, fair value	$ 595,500	$ 602,412

Restructuring and Other Costs -

Restructuring and Other Costs - Schedule of Restructuring and other costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost And Reserve [Line Items]
Total non-Merger related restructuring and other costs:	$ 22,816	$ 29,414	$ 42,135
Employee severance and benefit costs
Restructuring Cost And Reserve [Line Items]
Total non-Merger related restructuring and other costs:	14,526	26,321	25,243
Facility and lease termination costs
Restructuring Cost And Reserve [Line Items]
Total non-Merger related restructuring and other costs:	8,226	2,313	16,202
Other costs
Restructuring Cost And Reserve [Line Items]
Total non-Merger related restructuring and other costs:	$ 64	$ 780	$ 690

Restructuring and Other Costs_2

Restructuring and Other Costs - Liabilities Associated with Restructuring and Other Costs (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost And Reserve [Line Items]
Balance at the beginning of the period		$ 7,615	$ 5,381
Balance at the end of the period		7,585	7,615
Business exit costs and (gain) loss on termination of lease		8,200	2,300
Other Costs
Restructuring Cost And Reserve [Line Items]
Other restructuring expenses, non-cash		0	0
Business Restructuring Reserves
Restructuring Cost And Reserve [Line Items]
Balance at the beginning of the period		5,830	5,750
Expenses incurred (a)	[1]	14,591	27,112
Cash payments made		(13,764)	(27,032)
Balance at the end of the period		6,657	5,830
Business Restructuring Reserves | Employee Severance Costs
Restructuring Cost And Reserve [Line Items]
Balance at the beginning of the period		5,830	5,728
Expenses incurred (a)	[1]	14,574	26,321
Cash payments made		(13,747)	(26,219)
Balance at the end of the period		6,657	5,830
Business Restructuring Reserves | Other Costs
Restructuring Cost And Reserve [Line Items]
Balance at the beginning of the period			22
Expenses incurred (a)	[1]	17	791
Cash payments made		$ (17)	$ (813)
[1]	There were no non-cash restructuring and other expenses incurred for the years ended December 31, 2021 and 2020. The amount of expenses incurred for the years ended December 31, 2021 and 2020 excludes $8.2 million and $2.3 million, respectively, of facility lease closure and lease termination costs that are reflected as a reduction of operating lease right-of-use assets on the accompanying consolidated balance sheets under ASC 842.

Shareholders' Equity - Shares o

Shareholders' Equity - Shares of Common Stock Outstanding (Details) - Common Stock - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock shares, beginning balance	103,935	103,866	103,372
Repurchases of common stock	(1,500)	(1,256)	(1,323)
Issuances of common stock	1,329	1,325	1,817
Common stock shares, ending balance	103,764	103,935	103,866

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended												12 Months Ended
	Jun. 30, 2021shares	May 31, 2021shares	Mar. 31, 2021shares	Oct. 31, 2020shares	Sep. 30, 2020shares	Mar. 31, 2020shares	Aug. 31, 2019shares	Jun. 30, 2019shares	Feb. 28, 2019shares	Jan. 31, 2019shares	Apr. 30, 2018shares	Mar. 31, 2018shares	Dec. 31, 2021USD ($)NumberOfVote$ / sharesshares	Dec. 31, 2020USD ($)$ / shares	Dec. 31, 2019USD ($)	Dec. 05, 2019USD ($)	Feb. 26, 2018USD ($)
Class of Stock [Line Items]
Stock repurchase program, authorized amount																$ 300,000	$ 250,000
Common stock par value (USD per share) | $ / shares													$ 0.01	$ 0.01
Class C common stock dividends													$ 0	$ 0	$ 0
Common Class A [Member]
Class of Stock [Line Items]
Stock Repurchase Program 2021, Authorized Amount													$ 300,000
Common stock par value (USD per share) | $ / shares													$ 0.01
Stock repurchased during period, shares | shares													1,500,000
Stock repurchased during period, value													$ 117,500
Number of votes | NumberOfVote													1
Class B common stock, conversion ratio													1
Common Stock
Class of Stock [Line Items]
Stock repurchase program, authorized amount													$ 182,500
Stock repurchased during period, shares | shares	500,000	400,000	600,000	150,000	506,244	600,000	141,100	509,100	120,600	552,100	1,024,400	948,100	6,051,644
Common Class B [Member]
Class of Stock [Line Items]
Number of votes | NumberOfVote													1

Shareholders' Equity - Repurcha

Shareholders' Equity - Repurchase Activity (Details) - Common Stock - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended												12 Months Ended
	Jun. 30, 2021	May 31, 2021	Mar. 31, 2021	Oct. 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Aug. 31, 2019	Jun. 30, 2019	Feb. 28, 2019	Jan. 31, 2019	Apr. 30, 2018	Mar. 31, 2018	Dec. 31, 2021
Class of Stock [Line Items]
Stock repurchased (in shares)	500,000	400,000	600,000	150,000	506,244	600,000	141,100	509,100	120,600	552,100	1,024,400	948,100	6,051,644
Stock repurchased, average price paid per share (USD per share)	$ 81.20	$ 81.04	$ 74.18	$ 54.14	$ 59.26	$ 53.38	$ 49.93	$ 45.29	$ 41.40	$ 39.16	$ 36.60	$ 39.55
Stock repurchase program, shares purchased, value	$ 40,600	$ 32,416	$ 44,505	$ 8,122	$ 30,000	$ 32,029	$ 7,045	$ 23,055	$ 4,993	$ 21,623	$ 37,492	$ 37,493	$ 319,373

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Stock by Class (Details) - shares	Dec. 31, 2021	Dec. 31, 2020
Shares Authorized:
Common stock shares authorized (in shares)	600,000,000	600,000,000
Preferred stock shares authorized (in shares)	30,000,000	30,000,000
Common and Preferred stock, shares authorized (in shares)	630,000,000	630,000,000
Shares Issued:
Common stock shares issued (in shares)	103,764,000	103,935,000
Preferred stock shares issued (in shares)	0	0
Shares Outstanding:
Common stock shares outstanding (in shares)	103,763,635	103,934,738
Preferred stock shares outstanding (in shares)	0	0
Common Class A [Member]
Shares Authorized:
Common stock shares authorized (in shares)	300,000,000	300,000,000
Shares Issued:
Common stock shares issued (in shares)	103,763,635	103,934,738
Common Class B [Member]
Shares Authorized:
Common stock shares authorized (in shares)	300,000,000	300,000,000

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 234,831	$ 192,787	$ 131,258
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Basic weighted average common shares outstanding (in shares)	103,872	104,168	103,618
Effect of dilutive securities:
Stock options and other awards under deferred share-based compensation programs (in shares)	1,193	1,297	1,387
Diluted weighted average common shares outstanding (in shares)	105,065	105,465	105,005
Earnings per share:
Basic (USD per share)	$ 2.26	$ 1.85	$ 1.27
Diluted (USD per share)	$ 2.24	$ 1.83	$ 1.25

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Earnings Per Share [Abstract]
Anti-dillutive shares outstanding excluded from the computation of diluted earnings per share	145,342	582,760	277,128

Income Taxes - Components of In

Income Taxes - Components of Income before Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Domestic	$ 186,445	$ 122,659	$ (17,066)
Foreign	128,715	80,999	118,775
Income before provision for income taxes	$ 315,160	$ 203,658	$ 101,709

Income Taxes - Schedule of Comp

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Federal income taxes:
Current	$ 926	$ (15,537)	$ (13,952)
Deferred	45,819	10,188	(11,693)
Foreign income taxes:
Current	27,718	16,019	21,452
Deferred	(4,309)	(3,106)	(2,206)
State income taxes:
Current	5,163	14,229	2,850
Deferred	5,012	(10,922)	(26,000)
Income tax expense (benefit)	$ 80,329	$ 10,871	$ (29,549)

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Balance Sheet Statements Captions [Line Items]
Accumulated foreign earnings	$ 689,700
Foreign earnings previously taxed in the US, intended to be permanently reinvested	278,400
Foreign earnings previously taxed in the US, intended to be repatriated	411,300
Undistributed foreign earnings	$ 7,778	$ 10,912
Federal tax rate	21.00%
Valuation allowance increase (decrease)	$ 2,300	16,200
(Credited) charged to income tax expense	1,500	14,500
Foreign currency exchange		1,400
Gross unrecognized tax benefits	12,118	9,033	$ 23,238	$ 19,245
Accrued income tax interest and penalties	2,400	2,800
Decrease in unrecognized tax benefits	1,600
Research and Development Credit Carry Forwards | Canada Revenue Agency
Condensed Balance Sheet Statements Captions [Line Items]
Canadian research and development credit carry forwards	56,100	56,700
Valuation allowance, Canadian research and development credit carry forwards	56,100	56,700
Domestic Tax Authority
Condensed Balance Sheet Statements Captions [Line Items]
Operating loss carryforwards	$ 317,400	$ 260,600
Operating loss carryforwards, expiration year	2029	2029
State and Local Jurisdiction
Condensed Balance Sheet Statements Captions [Line Items]
Operating loss carryforwards	$ 840,400	$ 821,000
Foreign Jurisdictions
Condensed Balance Sheet Statements Captions [Line Items]
Operating loss carryforwards	98,900	$ 80,100
Decrease in unrecognized tax benefit in foreign jurisdictions	$ 3,100

Income Taxes - Schedule of Effe

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Expected income tax expense at statutory rate		$ 66,184	$ 42,768	$ 21,359
Change in income tax expense resulting from:
Foreign income inclusion		11,019	6,013	39,557
Foreign earnings not indefinitely reinvested		278	5,071
Foreign tax credits		(4,390)
Changes in income tax valuation allowance (all jurisdictions)		(1,462)	14,503	(68,537)
Change in fair value of contingent obligations		(122)	(769)	3,625
Share-based compensation		(5,662)	(2,800)	1,094
Research and general business tax credits	[1]	(8,902)	(12,872)	(1,871)
State and local taxes, net of federal benefit		11,978	6,924	(9,085)
Capital loss carryforward	[2]	(214)	(16,506)
Foreign rate differential		2,865	(1,777)	(3,595)
Changes in reserve for uncertain tax positions including interest		4,721	(18,839)	5,393
Provision to tax return and other deferred tax adjustments		(771)	(12,325)	(6,950)
Gain on sale of business			(2,350)
Base erosion and anti-abuse tax				(15,054)
Nondeductible executive compensation		1,649	367	1,802
Other, net		3,158	3,463	2,713
Income tax expense (benefit)		$ 80,329	$ 10,871	$ (29,549)
[1]	(a) Year ended December 31, 2021 included a $0.8 million valuation allowance release and year ended December 31, 2020 was offset by a $9.4 million valuation allowance.
[2]	(b) Years ended December 31, 2021 and 2020 are offset by $0.2 million and $16.5 million, respectively, in valuation allowances.

Income Taxes - Schedule of Ef_2

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Parenthetical) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Tax Credit Carryforward [Line Items]
Changes in income tax valuation allowance (all jurisdictions)	$ (1,462,000)	$ 14,503,000	$ (68,537,000)
Research and general business tax credits
Tax Credit Carryforward [Line Items]
Changes in income tax valuation allowance (all jurisdictions)	800	9,400
Capital loss carryforward
Tax Credit Carryforward [Line Items]
Changes in income tax valuation allowance (all jurisdictions)	$ 200	$ 16,500

Income Taxes - Summary of Valua

Income Taxes - Summary of Valuation Allowance (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Valuation Allowance [Line Items]
Balance at the beginning of the period	$ 7,615	$ 5,381	$ 4,587
(Credited) charged to income tax expense	1,500	14,500
Foreign currency exchange		1,400
Balance at the end of the period	7,585	7,615	5,381
SEC Schedule, 12-09, Valuation Allowance, Deferred Tax Asset
Valuation Allowance [Line Items]
Balance at the beginning of the period	100,310	84,159	150,316
Deferred tax assets assumed through acquisitions		479
Deferred tax assets released through divestitures		(271)
(Credited) charged to income tax expense	(1,462)	14,503	(68,537)
Charged to equity			42
Foreign currency exchange	(407)	1,440	2,338
Other adjustments	(479)
Balance at the end of the period	$ 97,962	$ 100,310	$ 84,159

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating losses	$ 134,143	$ 122,018
Tax credits	58,901	58,603
Deferred revenue		77,138
Employee compensation and other benefits	28,538	29,048
Allowance for doubtful accounts	1,787	1,739
Lease obligations	57,749	57,142
Accrued expenses	13,158	6,526
Prepaid royalty		3,451
Capital loss carryforward	20,021	20,157
Interest limitation carryforwards	30,847	20,219
Other	1,151	7,913
Total deferred tax assets	346,295	403,954
Less: valuation allowance	(97,962)	(100,310)
Net deferred tax assets	248,333	303,644
Deferred tax liabilities:
Undistributed foreign earnings	(7,778)	(10,912)
Right of use asset	(47,532)	(49,316)
Depreciation and amortization	(214,636)	(226,170)
Deferred revenue	(17,247)
Other	(3,814)	(2,404)
Total deferred tax liabilities	(291,007)	(288,802)
Net deferred tax assets (liabilities)	$ (42,674)
Net deferred tax assets (liabilities)		$ 14,842

Income Taxes - Schedule of Unre

Income Taxes - Schedule of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 9,033	$ 23,238	$ 19,245
Increases for tax positions in the current year	386	254	2,222
Increases for tax positions of prior years	4,233	3,237	2,255
Decreases for tax positions in prior year		(2,540)	(440)
Settlements with tax authorities	(1,131)
Impact of foreign currency translation	(169)		(44)
Impact of foreign currency translation		132
Lapse of statute limitations	(234)	(15,288)
Unrecognized tax benefits balance	$ 12,118	$ 9,033	$ 23,238

Revenue from Contracts with C_2

Revenue from Contracts with Customers - Narrative (Details) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2021USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Unsatisfied performance obligations under contracts with a contract term greater than one year	$ 6,700	$ 6,700
Revenue recognized, included in contract liabilities balance at beginning of period		611.9
Increase (decrease) in revenue recognized, allocated to performance obligation partially satisfied in previous periods		120.9
Revenue from change in estimate	$ 44	$ 23.5
Minimum
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Contract term		1 year
Maximum
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Contract term		5 years

Segment Information (Details)

Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)Segment	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Revenue	$ 5,212,970	$ 4,415,777	$ 4,675,815
Direct costs (exclusive of depreciation and amortization)	3,994,484	3,398,142	3,645,905
Selling, general, and administrative expenses	570,765	472,726	507,556
Operating income (loss)	389,280	293,143	237,754
Share-based compensation expense	65,204	58,491	55,193
Restructuring and other costs	22,816	29,414	42,135
Direct costs
Segment Reporting Information [Line Items]
Share-based compensation expense	33,220	31,347	29,011
Selling, general, and administrative expenses
Segment Reporting Information [Line Items]
Share-based compensation expense	31,984	27,144	26,182
Operating Segments
Segment Reporting Information [Line Items]
Direct costs (exclusive of depreciation and amortization)	3,961,264	3,366,795	3,616,894
Selling, general, and administrative expenses	436,506	366,342	367,932
Operating income (loss)	815,200	682,640	690,989
Corporate
Segment Reporting Information [Line Items]
Selling, general, and administrative expenses	102,275	79,240	113,442
Restructuring and other costs	22,816	29,414	42,135
Depreciation and amortization	235,625	222,352	242,465
Corporate | Direct costs
Segment Reporting Information [Line Items]
Share-based compensation expense	33,220	31,347	29,011
Corporate | Selling, general, and administrative expenses
Segment Reporting Information [Line Items]
Share-based compensation expense	31,984	27,144	26,182
Clinical Solutions | Operating Segments
Segment Reporting Information [Line Items]
Revenue	4,009,057	3,339,451	3,450,223
Direct costs (exclusive of depreciation and amortization)	3,005,938	2,513,240	2,637,016
Selling, general, and administrative expenses	353,990	283,633	280,674
Operating income (loss)	649,129	542,578	532,533
Commercial Solutions | Operating Segments
Segment Reporting Information [Line Items]
Revenue	1,203,913	1,076,326	1,225,592
Direct costs (exclusive of depreciation and amortization)	955,326	853,555	979,878
Selling, general, and administrative expenses	82,516	82,709	87,258
Operating income (loss)	$ 166,071	$ 140,062	$ 158,456

Operations by Geographic Loca_3

Operations by Geographic Location - Total Revenue by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues by Geographic Location
Revenue	$ 5,212,970	$ 4,415,777	$ 4,675,815
North America
Revenues by Geographic Location
Revenue	3,144,475	2,791,590	3,079,608
Europe, Middle East, and Africa
Revenues by Geographic Location
Revenue	1,333,540	1,059,968	1,055,007
Asia-Pacific
Revenues by Geographic Location
Revenue	594,163	465,116	444,819
Latin America
Revenues by Geographic Location
Revenue	140,792	99,103	96,381
United States
Revenues by Geographic Location
Revenue	$ 2,950,000	$ 2,640,000	$ 2,930,000
United States | Geographic Concentration Risk | Net Service Revenue
Revenues by Geographic Location
Concentration risk percentage	56.60%	59.90%	62.70%

Operations by Geographic Loca_4

Operations by Geographic Location - Long-Lived Assets by Geographic Area (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Long-Lived Assets by Geographic Location
Total property and equipment, net	$ 222,657	$ 216,200
North America
Long-Lived Assets by Geographic Location
Total property and equipment, net	165,446	161,531
Europe, Middle East, and Africa
Long-Lived Assets by Geographic Location
Total property and equipment, net	37,004	38,745
Asia-Pacific
Long-Lived Assets by Geographic Location
Total property and equipment, net	13,615	11,167
Latin America
Long-Lived Assets by Geographic Location
Total property and equipment, net	6,592	4,757
United States
Long-Lived Assets by Geographic Location
Total property and equipment, net	$ 160,000	$ 156,000

Concentration of Credit Risk -

Concentration of Credit Risk - Narrative (Details) - Customer Concentration Risk - Major Customer	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Service Revenue
Concentration Risk
Concentration risk percentage	10.00%	10.00%	10.00%
Accounts Receivable
Concentration Risk
Concentration risk percentage	10.00%	10.00%

Related-Party Transactions - Na

Related-Party Transactions - Narrative (Details) $ in Thousands	Oct. 06, 2021	Dec. 31, 2021USD ($)Customer	Dec. 31, 2020USD ($)Customer	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)Customer
Related Party Transaction [Line Items]
Revenue from related parties		$ 3,700	$ 1,800	$ 400	$ 400
Number of counterparties | Customer		2	1		2
Professional services expenses from transaction with related party		$ 600
Potential future cash consideration, in exchange of sale of company's contingent staffing business to related party		597	$ 3,664	(17,260)
Contingent consideration			1,800
Affiliated Entity
Related Party Transaction [Line Items]
Professional services expenses from transaction with related party				$ 1,100
Maximum
Related Party Transaction [Line Items]
Potential future cash consideration, in exchange of sale of company's contingent staffing business to related party			4,000
Rx Data Science Acquisitions
Related Party Transaction [Line Items]
Name of acquired entity	RxDataScience
Date of Acquisition	Oct. 6, 2021
Board of Directors
Related Party Transaction [Line Items]
Receivables from related party		$ 600	$ 1,300

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Thousands	Dec. 01, 2017numberOfAction	Dec. 31, 2021USD ($)	Mar. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Loss Contingencies [Line Items]
Contingent obligations related to acquisitions		$ 3,400
Recurring
Loss Contingencies [Line Items]
Contingent obligations related to acquisitions		17,997		$ 6,793
InVentiv Merger | Recurring
Loss Contingencies [Line Items]
Contingent obligations related to acquisitions			$ 6,200	$ 6,800
RxDataScience [Member]
Loss Contingencies [Line Items]
Contingent obligations related to acquisitions		$ 14,600
Pending Litigation | Bermudez and Vaitkuviene Actions
Loss Contingencies [Line Items]
Number of actions taken by plaintiff | numberOfAction	2

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2021USD ($)Planshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of plans | Plan		2
Number of shares authorized | shares		15,167,325
Number of shares available for future grants | shares		3,446,778
Share-based compensation expense | $		$ 65,204	$ 58,491	$ 55,193
Stock options granted | shares		0
Total intrinsic value of options exercised | $		$ 14,700	12,700	20,300
Income tax benefit recognized for stock-based compensation arrangements | $		13,800	$ 11,800	$ 10,800
Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation expense related to non-vested stock options | $		0
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant-date fair value of the RSUs granted | $ / shares			$ 62.12	$ 45.45
Total fair value of shares vested | $		$ 48,300	$ 43,000	$ 30,300
Granted (in shares) | shares		939,031
Performance Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant-date fair value of the RSUs granted | $ / shares			$ 62.50	$ 45
Fair value of shares vested | $		$ 6,400
Granted (in shares) | shares		59,055	0	0
2014 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
Employee Stock Purchase Plan (ESPP)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		6 months
Payroll deductions as a percentage of employee base salary, maximum	10.00%
Discount from market price of common stock, offering date	15.00%
Share-based compensation expense | $		$ 6,200	$ 5,800	$ 6,500
Shares issued (in shares) | shares		1,594,312
Shares available for future grants (in shares) | shares		1,905,688
Maximum | 2014 Equity Incentive Plan | Stock options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expiration term		10 years

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Valuation Assumptions (Details) - ESPP	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility - minimum	25.30%	27.70%	39.10%
Expected volatility - maximum	38.30%	55.10%	51.90%
Risk-free interest rate - minimum	0.06%	0.13%	1.88%
Risk-free interest rate - maximum	0.07%	0.95%	2.52%
Expected term (in years)	6 months	6 months	6 months

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)$ / sharesshares
Common Stock
Aggregate Intrinsic Value (in thousands)(a)
Share price (in USD per share)	$ 102.68
Stock options
Number of Options
Outstanding as of December 31, 2020 (in shares) | shares	663,559
Exercised (in shares) | shares	(279,072)
Outstanding as of December 31, 2021 (in shares) | shares	384,487
Vested and expected to vest as of December 31, 2021 (in shares) | shares	384,487
Exercisable as of December 31, 2021 (in shares) | shares	384,487
Weighted Average Exercise Price
Outstanding as of December 31, 2020 (in usd per share)	$ 30.12
Exercised (in usd per share)	33.31
Outstanding at December 31, 2020 (in usd per share)	27.81
Vested and expected to vest as of December 31, 2021 (in usd per share)	27.81
Exercisable as of December 31, 2021 (in usd per share)	$ 27.81
Weighted Average Remaining Contractual Life (in years)
Outstanding as of December 31, 2021 (in years)	3 years 3 months 3 days
Vested and expected to vest as of December 31, 2021 (in years)	3 years 3 months 3 days
Exercisable as of December 31, 2021 (in years)	3 years 3 months 3 days
Aggregate Intrinsic Value (in thousands)(a)
Outstanding as of December 31, 2021 (in usd) | $	$ 28,787
Vested and expected to vest as of December 31, 2021 (in usd) | $	28,787
Exercisable as of December 31, 2021 (in usd) | $	$ 28,787

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Restricted Stock Unit Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Stock Units (RSUs)
Number of Shares
Non-vested at December 31, 2020 (in shares)	1,909,882
Granted (in shares)	939,031
Vested (in shares)	(997,632)
Forfeited (in shares)	(226,094)
Non-vested at December 31, 2021 (in shares)	1,625,187	1,909,882
Unrecognized compensation expense (in millions)	$ 62.6
Weighted average period unrecognized compensation is expected to be recognized	1 year 10 months 24 days
Weighted Average Grant Date Fair Value
Non-vested at December 31, 2020 (in usd per share)	$ 51.98
Granted (in usd per share)	76.96
Vested (in usd per share)	48.45
Forfeited (in usd per share)	64.07
Non-vested at December 31, 2021 (in usd per share)	$ 66.90	$ 51.98
Performance Based Restricted Stock Units
Number of Shares
Non-vested at December 31, 2020 (in shares)	461,499
Granted (in shares)	59,055	0	0
Vested (in shares)	(136,665)
Forfeited (in shares)	(27,890)
Non-vested at December 31, 2021 (in shares)	355,999	461,499
Unrecognized compensation expense (in millions)	$ 10.7
Weighted average period unrecognized compensation is expected to be recognized	1 year 10 months 24 days
Weighted Average Grant Date Fair Value
Non-vested at December 31, 2020 (in usd per share)	$ 48.99
Granted (in usd per share)	75.43
Vested (in usd per share)	46.47
Forfeited (in usd per share)	58.71
Non-vested at December 31, 2021 (in usd per share)	$ 60.75	$ 48.99
Restricted Stock Units (RSUs)
Number of Shares
Non-vested at December 31, 2020 (in shares)	2,371,381
Granted (in shares)	998,086
Vested (in shares)	(1,134,297)
Forfeited (in shares)	(253,984)
Non-vested at December 31, 2021 (in shares)	1,981,186	2,371,381

Share-Based Compensation - Su_3

Share-Based Compensation - Summary of Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 65,204	$ 58,491	$ 55,193
Direct costs
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	33,220	31,347	29,011
Selling, general, and administrative expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 31,984	$ 27,144	$ 26,182

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Contributions to Defined Contribution Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Total defined contribution retirement plan contributions	$ 30,932	$ 15,049	$ 29,834

Employee Benefit Plans - Narrat

Employee Benefit Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Deferred Compensation Arrangement [Line Items]
Deferred compensation liabilities	$ 23.4	$ 22.3
Minimum
Deferred Compensation Arrangement [Line Items]
Allowable deferred amount, salary, percent	1.00%
Allowable deferred amount, commissions, percent	1.00%
Maximum
Deferred Compensation Arrangement [Line Items]
Allowable deferred amount, salary, percent	80.00%
Allowable deferred amount, commissions, percent	100.00%
Foreign Plan
Deferred Compensation Arrangement [Line Items]
Employer contribution amount	$ 23.2	$ 18.4	$ 10