PRA Health Sciences (PRAH) 10-Q 31 Oct 19 2019 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2019	Oct. 28, 2019
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-36732
Entity Registrant Name	PRA Health Sciences, Inc.
Entity Central Index Key	0001613859
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-3640387
Entity Address, Address Line One	4130 ParkLake Avenue
Entity Address, Address Line Two	Suite 400
Entity Address, City or Town	Raleigh
Entity Address, State or Province	NC
Entity Address, Postal Zip Code	27612
City Area Code	919
Local Phone Number	786-8200
Title of 12(b) Security	Common Stock $0.01 par value
Security Exchange Name	NASDAQ
Trading Symbol	PRAH
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
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		63,248,324

CONSOLIDATED CONDENSED BALANCE

CONSOLIDATED CONDENSED BALANCE SHEETS (UNAUDITED) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 181,767	$ 144,221
Restricted cash	23	488
Accounts receivable and unbilled services, net	702,636	568,099
Other current assets	76,489	69,547
Total current assets	960,915	782,355
Fixed assets, net	176,745	154,764
Lease right-of-use assets, net	181,813	0
Goodwill	1,484,506	1,494,762
Intangible assets, net	649,295	704,446
Other assets	47,182	50,140
Total assets	3,500,456	3,186,467
Current liabilities:
Accounts payable	58,565	43,734
Accrued expenses and other current liabilities	304,431	413,783
Current portion of operating lease liabilities	34,708	0
Advanced billings	474,999	441,357
Total current liabilities	872,703	898,874
Long-term debt, net	1,388,395	1,082,384
Long-term portion of operating lease liabilities	169,696	0
Deferred tax liabilities	73,522	100,712
Other long-term liabilities	49,397	53,077
Total liabilities	2,553,713	2,135,047
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock (100,000,000 authorized shares; $0.01 par value) Issued and outstanding -- none	0	0
Common stock (1,000,000,000 authorized shares; $0.01 par value) Issued and outstanding -- 65,735,974 and 65,394,526 at June 30, 2019 and December 31, 2018, respectively	632	654
Additional paid-in capital	975,233	960,535
Accumulated other comprehensive loss	(197,603)	(170,659)
Retained earnings	168,481	254,500
Equity attributable to PRA Health Sciences, Inc. stockholders	946,743	1,045,030
Noncontrolling interest	0	6,390
Total stockholders' equity	946,743	1,051,420
Total liabilities and stockholders' equity	$ 3,500,456	$ 3,186,467

CONSOLIDATED CONDENSED BALANC_2

CONSOLIDATED CONDENSED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	63,240,925	65,394,526
Common stock, shares outstanding	63,240,925	65,394,526

CONSOLIDATED CONDENSED STATEMEN

CONSOLIDATED CONDENSED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Revenue	$ 780,691	$ 717,596	$ 2,266,022	$ 2,142,274
Selling, general and administrative expenses	95,542	92,553	291,439	275,424
Transaction-related costs	572	43,837	572	32,709
Depreciation and amortization expense	29,264	28,270	85,462	84,163
Loss (gain) on disposal of fixed assets, net	256	(15)	900	21
Income from operations	95,788	38,812	262,526	184,556
Interest expense, net	(12,974)	(14,423)	(37,834)	(43,860)
Loss on modification or extinguishment of debt	(1,855)	(454)	(1,855)	(454)
Foreign currency gains (losses), net	5,408	(1,809)	1,864	(1,416)
Other income (expense), net	15	(68)	(66)	(201)
Income before income taxes and equity in income of unconsolidated joint ventures	86,382	22,058	224,635	138,625
Provision for income taxes	3,375	20,248	56,317	55,392
Income before equity in income of unconsolidated joint ventures	83,007	1,810	168,318	83,233
Equity in income of unconsolidated joint ventures, net of tax	0	44	0	118
Net income	83,007	1,854	168,318	83,351
Net income attributable to noncontrolling interest	0	(359)	(99)	(898)
Net income attributable to PRA Health Sciences, Inc.	$ 83,007	$ 1,495	$ 168,219	$ 82,453
Net income per share attributable to common stockholders:
Basic (in dollars per share)	$ 1.28	$ 0.02	$ 2.58	$ 1.29
Diluted (in dollars per share)	$ 1.25	$ 0.02	$ 2.53	$ 1.24
Weighted average common shares outstanding:
Basic (in shares)	64,771	64,261	65,096	63,891
Diluted (in shares)	66,213	66,506	66,607	66,258
Direct costs (exclusive of depreciation and amortization)
Cost of revenues	$ 389,304	$ 371,422	$ 1,153,441	$ 1,134,509
Reimbursable expenses
Cost of revenues	$ 169,965	$ 142,717	$ 471,682	$ 430,892

CONSOLIDATED CONDENSED STATEM_2

CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 83,007	$ 1,854	$ 168,318	$ 83,351
Other comprehensive loss:
Foreign currency translation adjustments, net of income tax of $2,183, $0, $2,447 and $0	(27,582)	(3,996)	(26,692)	(23,182)
Unrealized (losses) gains on derivative instruments, net of income tax of $(13), $381, $(1,624) and $2,004	(254)		(4,567)
Unrealized (losses) gains on derivative instruments, net of income tax of $(13), $381, $(1,624) and $2,004		1,041		5,613
Reclassification adjustments:
Losses on derivatives included in net income, net of income taxes of $398, $393, $1,056 and $1,314	1,213		2,972
Losses on derivatives included in net income, net of income taxes of $398, $393, $1,056 and $1,314		1,070		3,666
Comprehensive income (loss)	56,384	(31)	140,031	69,448
Comprehensive income attributable to noncontrolling interest	0	(193)	(175)	(823)
Comprehensive income (loss) attributable to PRA Health Sciences, Inc.	$ 56,384	$ (224)	$ 139,856	$ 68,625

CONSOLIDATED CONDENSED STATEM_3

CONSOLIDATED CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, tax	$ 2,183		$ 2,447
Unrealized (losses) gains on derivative instruments, tax (benefit)	(13)		(1,624)
Unrealized (losses) gains on derivative instruments, tax (benefit)		$ 381		$ 2,004
Losses on derivatives included in net income, tax	$ 398		$ 1,056
Losses on derivatives included in net income, tax		$ 393		$ 1,314

CONSOLIDATED CONDENSED STATEM_4

CONSOLIDATED CONDENSED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss (Note 13)	Retained Earnings	Non-controlling Interest
Balance at beginning of period (in shares) at Dec. 31, 2017		63,624,000
Balance at beginning of period at Dec. 31, 2017	$ 936,481	$ 636	$ 905,423	$ (136,470)	$ 161,182	$ 5,710
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)		436,000
Exercise of common stock options and other	1,389	$ 5	1,384
Stock-based compensation	6,299		6,299
Net income (loss)	39,215				38,981	234
Other comprehensive income (loss), net of tax	22,079			21,731		348
Balance at end of period (in shares) at Mar. 31, 2018		64,060,000
Balance at end of period at Mar. 31, 2018	944,876	$ 641	913,106	(114,739)	139,576	6,292
Balance at beginning of period (in shares) at Dec. 31, 2017		63,624,000
Balance at beginning of period at Dec. 31, 2017	936,481	$ 636	905,423	(136,470)	161,182	5,710
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	83,351
Acquisition of noncontrolling interest	0
Balance at end of period (in shares) at Sep. 30, 2018		64,915,000
Balance at end of period at Sep. 30, 2018	980,376	$ 649	940,444	(150,298)	183,048	6,533
Balance at beginning of period (in shares) at Mar. 31, 2018		64,060,000
Balance at beginning of period at Mar. 31, 2018	944,876	$ 641	913,106	(114,739)	139,576	6,292
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)		126,000
Exercise of common stock options and other	0	$ 1	(1)
Stock-based compensation	6,399		6,399
Net income (loss)	42,282				41,977	305
Other comprehensive income (loss), net of tax	(34,097)			(33,840)		(257)
Stock award distributions net of shares for tax withholding (in shares)		71,000
Stock award distributions, net of shares for tax withholding	(5,337)	$ 1	(5,338)
Balance at end of period (in shares) at Jun. 30, 2018		64,257,000
Balance at end of period at Jun. 30, 2018	954,123	$ 643	914,166	(148,579)	181,553	6,340
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)		568,000
Exercise of common stock options and other	17,740	$ 5	17,735
Stock-based compensation	8,544		8,544
Net income (loss)	1,854				1,495	359
Other comprehensive income (loss), net of tax	(1,885)			(1,719)		(166)
Stock award distributions net of shares for tax withholding (in shares)		90,000
Stock award distributions, net of shares for tax withholding	0	$ 1	(1)
Balance at end of period (in shares) at Sep. 30, 2018		64,915,000
Balance at end of period at Sep. 30, 2018	980,376	$ 649	940,444	(150,298)	183,048	6,533
Balance at beginning of period (in shares) at Dec. 31, 2018		65,395,000
Balance at beginning of period at Dec. 31, 2018	1,051,420	$ 654	960,535	(170,659)	254,500	6,390
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)		219,000
Exercise of common stock options and other	10,670	$ 2	10,668
Stock-based compensation (in shares)		33,000
Stock-based compensation	9,247		9,247
Net income (loss)	44,256				44,084	172
Other comprehensive income (loss), net of tax	(429)			(384)		(45)
Balance at end of period (in shares) at Mar. 31, 2019		65,647,000
Balance at end of period at Mar. 31, 2019	1,115,164	$ 656	980,450	(169,624)	297,165	6,517
Balance at beginning of period (in shares) at Dec. 31, 2018		65,395,000
Balance at beginning of period at Dec. 31, 2018	$ 1,051,420	$ 654	960,535	(170,659)	254,500	6,390
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)	464,564
Net income (loss)	$ 168,318
Acquisition of noncontrolling interest	6,565
Balance at end of period (in shares) at Sep. 30, 2019		63,241,000
Balance at end of period at Sep. 30, 2019	946,743	$ 632	975,233	(197,603)	168,481	0
Balance at beginning of period (in shares) at Mar. 31, 2019		65,647,000
Balance at beginning of period at Mar. 31, 2019	1,115,164	$ 656	980,450	(169,624)	297,165	6,517
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)		84,000
Exercise of common stock options and other	4,075	$ 1	4,074
Stock-based compensation (in shares)		5,000
Stock-based compensation	9,916		9,916
Net income (loss)	41,055				41,128	(73)
Other comprehensive income (loss), net of tax	(1,235)			(1,356)		121
Acquisition of noncontrolling interest	(5,275)		1,290			(6,565)
Balance at end of period (in shares) at Jun. 30, 2019		65,736,000
Balance at end of period at Jun. 30, 2019	1,163,700	$ 657	995,730	(170,980)	338,293	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and other (in shares)		328,000
Exercise of common stock options and other	15,415	$ 6	15,409
Stock-based compensation (in shares)		257,000
Stock-based compensation	11,244		11,244
Net income (loss)	83,007				83,007
Other comprehensive income (loss), net of tax	(26,623)			(26,623)
Repurchase and retirement of common stock (in shares)		(3,080,000)
Repurchase and retirement of common stock	(300,000)	$ (31)	(47,150)		(252,819)
Balance at end of period (in shares) at Sep. 30, 2019		63,241,000
Balance at end of period at Sep. 30, 2019	$ 946,743	$ 632	$ 975,233	$ (197,603)	$ 168,481	$ 0

CONSOLIDATED CONDENSED STATEM_5

CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 168,318	$ 83,351
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	85,462	84,163
Amortization of debt issuance costs	1,364	1,619
Amortization of terminated interest rate swaps	4,960	5,478
Stock-based compensation expense	30,407	20,469
Change in fair value of acquisition-related contingent consideration	0	32,868
Non-cash transaction-related costs	0	773
Unrealized foreign currency gains, net	(7,773)	(131)
Non-cash loss on extinguishment of debt	0	454
Deferred income tax (benefit) expense	(25,408)	17,499
Equity in income of unconsolidated joint ventures	0	(118)
Other reconciling items	792	52
Changes in operating assets and liabilities:
Accounts receivable, unbilled services and advanced billings	(104,589)	(12,552)
Other operating assets and liabilities	(4,289)	(319)
Payment of acquisition-related contingent consideration	(83,249)	(35,029)
Net cash provided by operating activities	65,995	198,577
Cash flows from investing activities:
Purchase of fixed assets	(61,210)	(40,086)
Proceeds received for interest on interest rate swap, net	1,076	125
Distributions from unconsolidated joint ventures	418	0
Proceeds from the sale of marketable securities	0	183
Proceeds from the sale of fixed assets	26	43
Net cash used in investing activities	(59,690)	(39,735)
Cash flows from financing activities:
Payment of acquisition-related contingent consideration	0	(79,663)
Repurchase and retirement of common stock	(300,000)	0
Borrowings on accounts receivable financing agreement	30,000	60,000
Borrowings on line of credit	40,000	0
Proceeds from issuance of long-term debt	300,000	0
Repayments on accounts receivable financing agreement	0	(10,000)
Repayments on line of credit	(40,000)	(91,500)
Repayments of long-term debt	(25,000)	(114,395)
Taxes paid related to net shares settlement of equity awards	0	(5,337)
Acquisition of noncontrolling interest	(4,138)	0
Proceeds from stock issued under employee stock purchase plan and stock option exercises	30,180	19,273
Net cash provided by (used in) financing activities	31,042	(221,622)
Effects of foreign exchange changes on cash, cash equivalents, and restricted cash	(266)	(2,275)
Change in cash, cash equivalents, and restricted cash	37,081	(65,055)
Cash, cash equivalents, and restricted cash, beginning of period	144,709	192,890
Cash, cash equivalents, and restricted cash, end of period	$ 181,790	$ 127,835

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The Company PRA Health Sciences, Inc. and its subsidiaries, or the Company, is a full-service global contract research organization providing a broad range of product development and data solution services to pharmaceutical and biotechnology companies around the world. The Company’s integrated services include data management, statistical analysis, clinical trial management, and regulatory and drug development consulting. Unaudited Interim Financial Information The interim consolidated condensed financial statements include the accounts of the Company and variable interest entities where the Company is the primary beneficiary. These financial statements are prepared in conformity with U.S. generally accepted accounting principles, or GAAP, and are unaudited. In the opinion of the Company’s management, all adjustments of a normal recurring nature necessary for a fair presentation have been reflected. Certain financial information that is normally included in annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, has been omitted. The accompanying interim consolidated condensed financial statements and related notes should be read in conjunction with the Company’s consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018 . The preparation of the interim consolidated condensed financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the interim consolidated condensed financial statements and the reported amounts of revenues and claims and expenses during the reporting period. Actual results could differ from those estimates. Recently Implemented Accounting Pronouncements On January 1, 2019, the Company adopted Accounting Standards Codification, or ASC, Topic 842, “Leases,” or ASC 842, using the revised modified retrospective approach provided by ASU No. 2018-11, “Leases (Topic 842): Targeted Improvements.” The revised modified retrospective approach recognizes the effects of initially applying the new leases standard as a cumulative effect adjustment to retained earnings as of the adoption date. Under this election, the provisions of ASC 840 apply to the accounting and disclosures for lease arrangements in the comparative periods in the Company's financial statements. The adoption of ASC 842 resulted in the recognition of lease liabilities of $211.7 million (recorded as $31.9 million in short-term lease liabilities and $179.8 million in long-term lease liabilities) and $187.1 million of lease right-of-use, or ROU, assets as of January 1, 2019. Upon adoption of ASC 842, the Company had lease obligations associated with deferred rent, lease loss liabilities, above market lease liabilities, and tenant improvement allowances, totaling $25.7 million , that were reclassified to the lease right-to-use assets. The Company had prepaid rent balances, totaling $1.1 million , that were reclassified as a reduction of the current portion of operating lease liabilities. The adoption of ASC 842 did not impact the consolidated condensed statement of operations for the nine months ended September 30, 2019 , consolidated condensed statement of cash flows, or earnings per share. See "Note 2 - Significant Accounting Policies" for further disclosures regarding the adoption of ASC 842. In August 2017, the Financial Accounting Standards Board, or FASB, issued ASU No. 2017-12, "Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities," in order to simplify certain aspects of hedge accounting and improve disclosures of hedging arrangements. ASU No. 2017-12 eliminates the need to separately measure and report hedge ineffectiveness and generally requires the entire change in fair value of a hedging instrument to be presented in the same income statement line as the hedged item. Entities must apply the amendments to cash flow and net investment hedge relationships that exist on the date of adoption using a modified retrospective approach. The presentation and disclosure requirements must be applied prospectively. The Company adopted this standard effective January 1, 2019 and the application of ASU No. 2017-12 did not have a material impact on the Company's consolidated condensed financial statements. In February 2018, the FASB issued ASU No. 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017, or the Act. The amendments in this update also require entities to disclose their accounting policy for releasing income tax effects from accumulated other comprehensive income. The Company adopted this standard effective January 1, 2019 and the application of ASU No. 2018-02 resulted in a reclassification of $1.4 million from accumulated other comprehensive loss to retained earnings for the stranded tax effects resulting from the Act. In October 2018, the FASB issued ASU No. 2018-16, "Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes," which amends ASC 815, Derivatives and Hedging. This ASU adds the OIS rate based on SOFR to the list of permissible benchmark rates for hedge accounting purposes. The Company adopted ASU No. 2018-16 concurrent with adoption of ASU No. 2017-12, on January 1, 2019, and the application of ASU No. 2018-16 did not have a material impact on the Company’s consolidated condensed financial statements. Recently Issued Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-04, “Intangibles-Goodwill and Other: Simplifying the Test for Goodwill Impairment,” in order to simplify the subsequent measurement of goodwill by eliminating the Step 2 goodwill impairment test. Under the amendments in this ASU, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity will then recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The guidance is effective for fiscal years beginning after December 15, 2019, with early adoption permitted. The adoption of ASU No. 2017-04 is not expected to have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, "Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract," in order to expand on the FASB's guidance of capitalized costs incurred in a cloud computing arrangement. The amendments in this update require an entity (customer) in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which implementation costs to capitalize as an asset related to the service contract and which costs to expense. The guidance is effective for the reporting period beginning after December 15, 2019, and interim periods therein, with early adoption permitted. The adoption of ASU No. 2018-15 is not expected to have a material impact on the Company's consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology and require consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The guidance is effective for the reporting period beginning after December 15, 2019, and the interim periods therein. The adoption of ASU 2016-13 is not expected to have a material impact on the Company’s consolidated financial statements. Cash, Cash Equivalents, and Restricted Cash The Company receives cash advances from its customers to be used for the payment of investigator fees and other pass-through expenses. The terms of certain customer contracts require that such advances be maintained in separate escrow accounts; thus, these accounts are not commingled with the Company’s cash and cash equivalents. These accounts are presented separately in the consolidated condensed balance sheets as restricted cash. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated condensed balance sheets that sum to the total of the same amounts shown in the consolidated condensed statements of cash flows (in thousands): September 30, December 31, 2019 2018 2018 2017 Cash and cash equivalents $ 181,767 $ 127,517 $ 144,221 $ 192,229 Restricted cash 23 318 488 661 Total cash, cash equivalents, and restricted cash $ 181,790 $ 127,835 $ 144,709 $ 192,890

Significant Accounting Policies

Significant Accounting Policies	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Significant accounting policies are detailed in "Note 2: Significant Accounting Policies" of the Annual Report on Form 10-K for the year ended December 31, 2018 . Significant changes to the Company's accounting policies as a result of adopting ASC 842 are discussed below: On January 1, 2019, the Company adopted ASC 842 using the revised modified retrospective approach. The revised modified retrospective approach recognizes the effects of initially applying the new leases standard as a cumulative effect adjustment to retained earnings as of the adoption date. Under this election, the provisions of ASC 840 apply to the accounting and disclosures for lease arrangements in the comparative periods in an entity’s financial statements. In addition, the Company elected the package of practical expedients permitted under the transition guidance within ASC 842, in which the Company need not reassess (i) the historical lease classification, (ii) whether any expired or existing contract is or contains a lease, or (iii) the initial direct costs for any existing leases. The Company’s material lease obligations are operating leases for office and other facilities in which the Company conducts business. The facility leases generally provide an initial lease term ranging from three to 20 years and include one or more optional extensions. The Company's leases have remaining lease terms of one year to 17 years . The leases typically include rent escalation clauses and for some markets the leases frequently include periodic market adjustments to the base rent over the term of the lease. In certain instances, the Company subleases space that has been exited or is no longer required. The Company’s sublease income is immaterial. Upon the initial application of ASC 842 on January 1, 2019, or the transition date, lease liabilities were measured by using the remaining minimum rental payments under ASC 840. The Company’s ASC 840 minimum rental payments include executory costs and rental payments that depend on an index or rate are calculated based on the rate in effect at the transition date. The lease liability is measured at the present value of future lease payments, discounted using the discount rate as of the transition date. In addition to recognizing the lease liability, the Company recognized a corresponding asset representing its right to use the underlying asset over the lease term, referred to as the lease ROU asset. The ROU asset is initially measured as the amount of lease liability, adjusted for any initial lease costs or lease payments made before or at the commencement of the lease, and reduced by any lease incentives and deferred rent. As of the transition date, the Company’s leases consisted of only operating leases and upon recognition of the lease liability and ROU assets, there was no adjustment to retained earnings. All leases entered into after January 1, 2019 are accounted for under ASC 842. Under ASC 842, a contract is or contains a lease when (i) explicitly or implicitly identified assets have been deployed in the contract and (ii) the customer obtains substantially all of the economic benefits from the use of that underlying asset and directs how and for what purpose the asset is used during the term of the contract. The Company also considers whether its service arrangements include the right to control the use of an asset. The Company determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The commencement date of the lease is the date that the lessor makes an underlying asset available for use by a lessee. At the lease commencement date, a lease liability is recognized based on the present value of the lease payments not yet paid, discounted using the discount rate for the lease at lease commencement. When readily determinable, the discount rate used to calculate the lease liability is the rate implicit in the lease. As the Company's leases typically do not provide an implicit rate, the Company uses its incremental borrowing rate based on the lease term and economic environment at the lease commencement date. The lease term used to calculate the lease liability includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. With limited exceptions, the nature of the Company's facility leases is such that there are not economic or other conditions that would indicate that it is reasonably certain at lease commencement that the Company will exercise options to extend the term. The Company determines if its lease obligations are operating or finance leases at the lease commencement date and considers whether the lease grants an option to purchase the underlying asset that it is reasonably certain to exercise, the remaining economic life of the underlying asset, the present value of the sum of the remaining lease payments and any residual value guaranteed, and the nature of the asset. The initial measurement of the lease liability is determined based on the future lease payments, which may include lease payments that depend on an index or a rate (such as the consumer price index or other market index). The Company initially measures payments based on an index or rate by using the applicable rate at lease commencement and subsequent changes in such rates are recognized as variable lease costs. Variable payments that do not depend on a rate or index are not included in the lease liability and are recognized as they are incurred. The Company’s contracts that include a lease component generally include additional services that are transferred to the lessee (e.g., common-area maintenance services), which are nonlease components. Contracts typically also include other costs and fees that do not provide a separate service to the lessee, such as costs paid by the lessee to reimburse the lessor for administrative costs or payment for the lessor’s costs for property taxes, insurance related to the leased asset, and other lessor costs. The Company elected the practical expedient to account for the lease and nonlease components as a single lease component. At the lease commencement date, the Company recognizes a ROU asset representing its right to use the underlying asset over the lease term. If significant events, changes in circumstances, or other events indicate that the lease term has changed, the Company would reassess lease classification, remeasure the lease liability by using revised inputs as of the reassessment date, and adjust the ROU asset. These reassessment events are typically related to the exercise of optional renewals or significant new investments in leasehold improvements. The costs of services and costs related to reimbursements of the lessor’s cost are generally variable rent obligations, which are excluded from the future lease payments included in the lease liability. For leases with a term of one year or less, or short-term leases, the Company has elected to not recognize the lease liability for these arrangements and the lease payments are recognized in the consolidated statement of operations on a straight-line basis over the lease term. The total expense for the operating lease liability is recognized on a straight-line basis over the lease term, beginning on the lease commencement date. The Company classifies the lease costs within operating expenses consistent with the classification policies for all other operating costs. The components of lease expense were as follows for the three and nine months ended September 30, 2019 (in thousands): Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Lease cost: Operating lease cost $ 9,788 $ 28,583 Short-term lease cost 725 2,033 Variable lease cost 2,175 5,796 Lease income (47 ) (130 ) Net lease cost $ 12,641 $ 36,282 Supplemental cash flow information related to leases was as follows for the three and nine months ended September 30, 2019 (in thousands): Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Cash paid for amounts included in the measurements of lease liabilities, all included in operating cash flows $ 9,772 $ 28,262 Right-of-use assets obtained in exchange for lease obligations 5,100 26,148 Supplemental balance sheet information related to leases was as follows as of September 30, 2019 : As of September 30, 2019 Weighted average remaining lease term 8.0 years Weighted average discount rate 4.3% Maturities of operating lease liabilities were as follows as of September 30, 2019 (in thousands): 2019 (remaining) $ 9,192 2020 42,946 2021 39,210 2022 31,454 2023 25,891 Thereafter 93,864 Total lease payments 242,557 Less imputed interest (38,153 ) Total $ 204,404 As of September 30, 2019 , the Company has an additional non-cancelable operating lease that has not yet commenced with future lease payments totaling $0.5 million . This lease will commence in October 2019 with an initial lease term of two years . As of December 31, 2018 , the Company disclosed the following future non-cancelable rent obligations as determined under ASC 840 (in thousands): 2019 $ 43,675 2020 40,948 2021 37,469 2022 30,238 2023 24,235 Thereafter 90,978 Total lease payments $ 267,543

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Company records certain assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy that prioritizes the inputs used to measure fair value is described below. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: • Level 1 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs. The carrying amount of financial instruments, including cash and cash equivalents, accounts receivable, unbilled services, contract assets, accounts payable and advanced billings, approximate fair value due to the short maturities of these instruments. Recurring Fair Value Measurements The following table summarizes the fair value of the Company’s financial liabilities that are measured on a recurring basis as of September 30, 2019 (in thousands): Level 1 Level 2 Level 3 Total Liabilities: Interest rate swaps $ — $ 3,805 $ — $ 3,805 Total $ — $ 3,805 $ — $ 3,805 Non-recurring Fair Value Measurements Certain assets and liabilities are carried on the accompanying consolidated condensed balance sheets at cost and are not remeasured to fair value on a recurring basis. These assets include finite-lived intangible assets that are tested for impairment when a triggering event occurs and goodwill and identifiable indefinite-lived intangible assets that are tested for impairment annually on October 1 or when a triggering event occurs. As of September 30, 2019 , assets carried on the balance sheet and not remeasured to fair value on a recurring basis totaled approximately $2,133.8 million and are identified as Level 3 assets. These assets are comprised of goodwill of $1,484.5 million and identifiable intangible assets, net of $649.3 million . Refer to "Note 7 - Revolving Credit Facilities and Long-Term Debt" for additional information regarding the fair value of long-term debt balances.

Concentration of Credit Risk

Concentration of Credit Risk	9 Months Ended
	Sep. 30, 2019
Risks and Uncertainties [Abstract]
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to credit risk consist of cash and cash equivalents, accounts receivable, unbilled services, and derivatives. As of September 30, 2019 , substantially all of the Company’s cash and cash equivalents and derivatives were held in or invested with large financial institutions. Accounts receivable include amounts due from pharmaceutical and biotechnology companies. The Company establishes an allowance for potentially uncollectible receivables. In management’s opinion, there is no additional material credit risk beyond amounts provided for such losses. There were no individual customers for which revenue was greater than 10% of consolidated revenue in the three and nine months ended September 30, 2019 and 2018. Accounts receivable and unbilled services from individual customers that were equal to or greater than 10% of consolidated accounts receivable and unbilled services at the respective dates were as follows: September 30, December 31, 2019 2018 Customer A 10.6 % 12.2 % Customer B 15.5 % 11.4 %

Accounts Receivable, Unbilled S

Accounts Receivable, Unbilled Services and Advanced Billings	9 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Accounts Receivable, Unbilled Services and Advanced Billings	Accounts Receivable, Unbilled Services and Advanced Billings Accounts receivable and unbilled services were as follows (in thousands): September 30, December 31, 2019 2018 Accounts receivable $ 557,077 $ 437,001 Unbilled services 147,952 133,147 Total accounts receivable and unbilled services 705,029 570,148 Less allowance for doubtful accounts (2,393 ) (2,049 ) Total accounts receivable and unbilled services, net $ 702,636 $ 568,099 Unbilled services as of September 30, 2019 and December 31, 2018 includes $75.1 million and $66.6 million , respectively, of contract assets where the Company’s right to bill is conditioned on criteria other than the passage of time. Impairment losses on contract assets were immaterial in the three and nine months ended September 30, 2019 and 2018 . Advanced billings were as follows (in thousands): September 30, December 31, 2019 2018 Advanced billings $ 474,999 $ 441,357 The $33.6 million increase in advanced billings from December 31, 2018 to September 30, 2019 was primarily due to the timing of customer payments. During the nine months ended September 30, 2019 and 2018 , the Company recognized revenue of $398.4 million and $382.5 million related to advanced billings recorded as of January 1, 2019 and 2018, respectively. Performance Obligations Revenue recognized from reimbursable expenses and services completed in prior periods was $14.8 million and $65.2 million for the three and nine months ended September 30, 2019 , respectively, and $24.4 million and $57.3 million for the three and nine months ended September 30, 2018 , respectively. This primarily relates to adjustments attributable to changes in estimates such as estimated total contract costs, and from contract modifications on long-term fixed price contracts executed in the current period, which results in changes to the transaction price. The Company does not disclose the value of the transaction price allocated to unsatisfied performance obligations on contracts that have an original contract term of less than one year. These contracts are short in duration and revenue recognition generally follows the delivery of the promised services. The total transaction price for the undelivered performance obligation on contracts with an original initial contract term greater than one year is $5.2 billion as of September 30, 2019 . This amount includes reimbursement revenue. 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

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill The changes in the carrying amount of goodwill by reportable segment are as follows (in thousands): Clinical Research Data Solutions Consolidated Balance at December 31, 2018 $ 1,017,903 $ 476,859 $ 1,494,762 Currency translation (10,256 ) — (10,256 ) Balance at September 30, 2019 $ 1,007,647 $ 476,859 $ 1,484,506 There are no accumulated impairment charges as of September 30, 2019 and December 31, 2018 . Intangible Assets Intangible assets consist of the following (in thousands): September 30, 2019 December 31, 2018 Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Customer relationships $ 551,020 $ (127,070 ) $ 423,950 $ 555,915 $ (103,248 ) $ 452,667 Trade names (finite-lived) 28,524 (15,636 ) 12,888 28,505 (12,810 ) 15,695 Patient list and other intangibles 44,474 (34,476 ) 9,998 44,474 (30,939 ) 13,535 Database 137,100 (52,651 ) 84,449 137,100 (32,561 ) 104,539 Total finite-lived intangible assets 761,118 (229,833 ) 531,285 765,994 (179,558 ) 586,436 Trade names (indefinite-lived) 118,010 — 118,010 118,010 — 118,010 Total intangible assets $ 879,128 $ (229,833 ) $ 649,295 $ 884,004 $ (179,558 ) $ 704,446 Amortization expense was $17.1 million and $51.4 million for the three and nine months ended September 30, 2019 , respectively, and $17.9 million and $54.0 million for the three and nine months ended September 30, 2018 , respectively. The estimated future amortization expense of finite-lived intangible assets is expected to be as follows (in thousands): 2019 (remaining) $ 17,079 2020 68,711 2021 63,619 2022 49,244 2023 37,515 2024 and thereafter 295,117 Total $ 531,285

Revolving Credit Facilities and

Revolving Credit Facilities and Long-Term Debt	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Revolving Credit Facilities and Long-Term Debt	Revolving Credit Facilities and Long-Term Debt Long-term debt consists of the following (in thousands): September 30, December 31, 2019 2018 Term loans, first lien $ 1,191,533 $ 916,533 Accounts receivable financing agreement 200,000 170,000 Total debt 1,391,533 1,086,533 Less current portion of long-term debt — — Total long-term debt 1,391,533 1,086,533 Less debt issuance costs (3,138 ) (4,149 ) Total long-term debt, net $ 1,388,395 $ 1,082,384 Principal payments on long-term debt are due as follows (in thousands): Current maturities of long-term debt: 2019 (remaining) $ — 2020 — 2021 1,391,533 2022 — Total $ 1,391,533 2016 Credit Facilities As collateral for borrowings under the senior secured credit facilities, or 2016 Credit Facilities, the Company granted a pledge on primarily all of its assets, and the stock of wholly-owned U.S. restricted subsidiaries. The Company is subject to certain financial covenants, which require the Company to maintain certain debt-to-EBITDA and interest expense-to-EBITDA ratios. The 2016 Credit Facilities also contain covenants that, among other things, restrict the Company’s ability to create any liens, make investments and acquisitions, incur or guarantee additional indebtedness, enter into mergers or consolidations and other fundamental changes, conduct sales and other dispositions of property or assets, enter into sale-leaseback transactions or hedge agreements, prepay subordinated debt, pay dividends or make other payments in respect of capital stock, change the line of business, enter into transactions with affiliates, enter into burdensome agreements with negative pledge clauses, and make subsidiary distributions. After giving effect to the applicable restrictions on the payment of dividends under the 2016 Credit Facilities, subject to compliance with applicable law, as of September 30, 2019 and December 31, 2018 , all amounts in retained earnings were free of restriction and were available for the payment of dividends. The 2016 Credit Facilities also contain customary representations, warranties, affirmative covenants, and events of default. The variable interest rate is a rate equal to the London Interbank Offered Rate, or LIBOR, or the adjusted base rate, or ABR, at the election of the Company, plus a margin based on the ratio of total indebtedness to EBITDA. The margin ranges from 1.00% to 2.00% , in the case of LIBOR loans, and 0.00% to 1.00% , in the case of ABR loans. The Company has the option of 1 , 2 , 3 or 6 month base interest rates. For the nine months ended September 30, 2019 , the weighted average interest rate on the first lien term loan was 3.75% . On September 3, 2019, the Company received the proceeds from a $300.0 million incremental term loan under the 2016 Credit Facilities, or the Incremental Borrowing. The Incremental Borrowing was used to fund the share repurchase which is discussed further in "Note 8 - Stockholders' Equity". In accordance with the guidance in ASC 470-50, "Debt - Modifications and Extinguishments," the Incremental Borrowing was accounted for as a debt modification. The Incremental Borrowing resulted in a $1.9 million loss on modification of debt, which consists of third-party fees associated with the transaction. The Company's voluntary term loan prepayments made during 2018 and 2019 fully satisfied all required quarterly principal payments through maturity. 2016 Revolver The revolving credit facility under the 2016 Credit Facilities, or 2016 Revolver, provides for $225.0 million of potential borrowings and expires on December 6, 2021. The interest rate on the 2016 Revolver is based on the LIBOR with a 0% LIBOR floor or ABR , at the election of the Company, plus an applicable margin, based on the leverage ratio of the Company. The Company, at its discretion, may elect interest periods of 1 , 2 , 3 or 6 months. The Company is required to pay to the lenders a commitment fee for unused commitments of 0.2% to 0.4% based on the Company’s debt-to-EBITDA ratio. At September 30, 2019 and December 31, 2018 , the Company had no outstanding borrowings under the 2016 Revolver. In addition, at September 30, 2019 and December 31, 2018 , the Company had $5.2 million and $5.4 million , respectively, in letters of credit outstanding, which are secured by the 2016 Revolver. Accounts Receivable Financing Agreement The Company had $200.0 million and $170.0 million outstanding on its accounts receivable financing agreement as of September 30, 2019 and December 31, 2018 , respectively. Loans under the accounts receivable financing agreement accrue interest at either a reserve-adjusted LIBOR or a base rate , plus 1.25% . The Company may prepay loans upon one business day's prior notice and may terminate the accounts receivable financing agreement with 15 days’ prior notice. For the nine months ended September 30, 2019 , the weighted average interest rate on the accounts receivable financing agreement was 3.86% . The accounts receivable financing agreement contains various customary representations and warranties and covenants, and default provisions that provide for the termination and acceleration of the commitments and loans under the agreement in circumstances including, but not limited to, failure to make payments when due, breach of representations, warranties or covenants, certain insolvency events or failure to maintain the security interest in the trade receivables, and defaults under other material indebtedness. At December 31, 2018 , there was $30.0 million of remaining capacity available under the accounts receivable financing agreement. At September 30, 2019 , there was no remaining capacity available under the accounts receivable financing agreement. Fair Value of Debt The estimated fair value of the Company’s debt and outstanding borrowings under its revolving credit facilities was $1,390.0 million and $1,084.2 million at September 30, 2019 and December 31, 2018 , respectively. The fair values of the term loans, borrowings under credit facilities, and accounts receivable financing agreement were determined based on Level 2 inputs, which are primarily based on rates at which the debt is traded among financial institutions adjusted for the Company's credit standing.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Stockholders' Equity Note [Abstract]
Stockholders' Equity	Stockholders’ Equity Authorized Shares The Company is authorized to issue up to one billion shares of common stock, with a par value of $0.01 . The Company is authorized to issue up to one hundred million shares of preferred stock, with a par value of $0.01 . Share Repurchase Program On August 30, 2019 , the Company's Board of Directors, or the Board, approved a share repurchase program, or the Repurchase Program, authorizing the repurchase of up to $500.0 million of the Company's common stock in open market purchases, privately-negotiated transactions, secondary offerings, block trades or otherwise in accordance with all applicable securities laws and regulations, including through Rule 10b5-1 trading plans and pursuant to Rule 10b-18 under the Securities Exchange Act of 1934, as amended, or the Exchange Act. The Repurchase Program does not obligate the Company to repurchase any particular amount of its common stock, and it may be modified, suspended or terminated at any time at the Board's discretion. The Repurchase Program expires on December 31, 2021. On September 6, 2019, KKR PRA Investors L.P., or KKR, sold 6,666,684 shares of the Company's common stock as part of a secondary offering, or the Secondary Offering, of which the Company repurchased from the underwriter, and subsequently retired, 3,079,765 shares at a price of $97.41 per share, for an aggregate purchase price of approximately $300.0 million . The Company incurred expenses in connection with the Secondary Offering of $0.6 million during the three and nine months ended September 30, 2019 . The expenses are included in transaction-related costs in the accompanying consolidated condensed statement of operations. As of September 30, 2019 , the Company has remaining authorization to repurchase up to $200.0 million of its common stock under the Repurchase Program. Noncontrolling Interest Below is a summary of noncontrolling interest for the nine months ended September 30 (in thousands): 2019 2018 Balance as of January 1, $ 6,390 $ 5,710 Comprehensive income Net income 99 898 Foreign currency adjustments, net of income tax 76 (75 ) Acquisition of noncontrolling interest (6,565 ) — Balance as of September 30, $ — $ 6,533 On June 1, 2017, the Company and Takeda Pharmaceutical Company Ltd., or Takeda, closed on a joint venture transaction that enables the Company to provide clinical trial delivery and pharmacovigilance services as a strategic partner of Takeda in Japan. The joint venture transaction was effectuated through the creation of a new legal entity, Takeda PRA Development Center KK, or the TDC joint venture. On May 31, 2019, per the terms of the agreement, the TDC joint venture dissolved and the Company acquired Takeda's interest for $4.1 million

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation Stock Option and RSA/RSU Activity The 2018 Stock Incentive Plan, or the 2018 Plan, was approved by stockholders at the annual meeting on May 31, 2018. The 2018 Plan allows for the issuance of stock options, stock appreciation rights, restricted shares and restricted stock units, other stock-based awards, and performance compensation awards as permitted by applicable laws. The 2018 Plan authorized the issuance of 2,000,000 shares of common stock plus all shares that remained available under the prior plan on May 31, 2018. The Company granted 1,150,000 service-based options and 352,036 restricted stock awards and units, or RSAs/RSUs, with a total grant date fair value of $37.8 million and $34.2 million , respectively, during the nine months ended September 30, 2019 . Aggregated information regarding the Company’s option plans is summarized below: Options Wtd. Average Exercise Price Wtd. Average Remaining Contractual Life (in years) Intrinsic Value (millions) Outstanding at December 31, 2018 4,641,600 $ 62.29 7.8 $ 149.7 Granted 1,150,000 98.42 Exercised (464,564 ) 33.86 Expired or forfeited (199,550 ) 82.92 Outstanding at September 30, 2019 5,127,486 $ 72.17 7.7 $ 144.8 Exercisable at September 30, 2019 1,975,811 $ 42.71 6.0 $ 112.5 The Company’s RSAs/RSUs activity in 2019 is as follows: Awards Wtd. Average Grant-Date Fair Value Intrinsic Value (millions) Unvested December 31, 2018 344,250 $ 81.39 $ 31.7 Granted 352,036 97.06 Forfeited (40,500 ) 80.72 Vested (22,750 ) 61.57 Unvested September 30, 2019 633,036 $ 90.87 $ 62.8 Employee Stock Purchase Plan In April 2017, the Board approved the PRA Health Sciences, Inc. 2017 Employee Stock Purchase Plan, or ESPP, which was approved by the Company’s shareholders on June 1, 2017. The ESPP allows eligible employees to authorize payroll deductions of up to 15% of their base salary or wages to be applied toward the purchase of shares of the Company’s common stock on the last trading day of any offering period. Participating employees will purchase shares of the Company's common stock at a discount of up to 15% on the lesser of the closing price of the Company's common stock on the NASDAQ Global Select Market (i) on the first trading day of the offering period or (ii) the last day of any offering period. Offering periods under the ESPP will generally be in six month increments, with the administrator of the ESPP having the right to establish different offering periods. The Company recognized stock-based compensation expense of $3.0 million and $2.5 million associated with the ESPP during the nine months ended September 30, 2019 and 2018 , respectively. As of September 30, 2019 , there have been 242,329 shares issued and 2,757,671 shares reserved for future issuance under the ESPP. Stock-based Compensation Expense Stock-based compensation expense related to employee stock plans are summarized below (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Direct costs $ 3,685 $ 2,451 $ 9,780 $ 6,900 Selling, general and administrative 7,559 5,319 20,627 13,569 Transaction-related costs — 773 — 773 Total stock-based compensation expense $ 11,244 $ 8,543 $ 30,407 $ 21,242

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company’s effective income tax rate was 25.1% and 40.0% for the nine months ended September 30, 2019 and 2018 , respectively. The effective tax rate for the nine months ended September 30, 2018 included the effect of an increase in the fair value of the earn-out liability related to the stock acquisition of Symphony Health, which was not included in taxable income, but instead increased tax stock basis. The variation between the Company’s effective income tax rate and the U.S. statutory rate of 21% for the nine months ended September 30, 2019 is primarily due to (i) the U.S. inclusion of amounts related to the estimated tax on global intangible low-taxed income, or GILTI, (ii) state income taxes, and (iii) the effects of other jurisdictional and permanent differences, including excess tax benefits. Significant judgment is required related to the application of the recent U.S. tax reform, or the Act, particularly with respect to GILTI and the base erosion anti-abuse tax, or BEAT, provisions. If changes occur in the Company’s tax structure, the structure of its arrangements, interpretations, or regulations that clarify these or other provisions of the Act, these changes could have a material effect on the Company’s tax provision. In the quarter ended September 30, 2019, the Company updated its analysis of BEAT and its impact on the annual estimated effective tax rate for the 2019 tax year to reflect revisions to contractual arrangements. GAAP requires a two-step approach when evaluating uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence demonstrates that it is more likely than not that the position will be sustained upon audit, including resolution of any related appeals or litigation processes. The second step is to quantify the amount of tax benefit to recognize as the amount that is cumulatively more than 50% likely to be realized upon ultimate settlement with the taxing authorities. During the nine months ended September 30, 2019 , the liability for uncertain tax positions increased by $18.7 million . This increase in the liability for uncertain tax positions had no impact on income tax expense for the nine months ended September 30, 2019 as it was previously accrued. If such uncertain positions were recognized, they would impact the effective tax rate.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings The Company is involved in legal proceedings from time to time in the ordinary course of its business, including employment claims and claims related to other business transactions. Although the outcome of such claims is uncertain, management believes that these legal proceedings will not have a material adverse effect on the financial condition or results of future operations of the Company. The Company is currently a party to litigation with the City of Sao Paulo, Brazil. The dispute relates to whether the export of services provided by the Company is subject to a local tax on services. The Company has not recorded a liability associated with the claim, which totaled $4.9 million at September 30, 2019 , given that it is not deemed probable the Company will incur a loss related to this case. However, a deposit totaling $4.9 million has been made to the Brazilian court in order to annul the potential tax obligation and to avoid the accrual of additional interest and penalties. This balance is recorded in other assets on the consolidated condensed balance sheet. In June 2015, the Judiciary Court of Justice of the State of Sao Paulo ruled in the favor of the Company; however, the judgment was appealed by the City of Sao Paulo. In September 2017, a judge from the Superior Court of Justice of Brazil denied relief to the City of Sao Paulo's appeal and upheld the lower court's ruling in favor of the Company for the years 2005 to 2012, and in the period from January to October 2013. The judge from the Superior Court of Justice of Brazil also ruled that the Company must appeal the lower court's verdict for October 2013 and the subsequent periods as the Judiciary Court of Justice of the State of Sao Paulo only reviewed the facts that pertained to the period before October 2013. The Company expects to recover the full amount of the deposit when the case is settled.

Derivatives

Derivatives	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives The Company is exposed to certain risks relating to its ongoing business operations. The primary risk that the Company seeks to manage by using derivative instruments is interest rate risk arising from movement in market interest rates. Accordingly, the Company has instituted an interest rate hedging program that uses interest rate swaps designated as cash flow hedges to mitigate interest rate volatility. The Company swaps the difference between fixed and variable interest amounts calculated by reference to an agreed-upon notional principal amount, at specified intervals. The Company’s interest rate contracts are designated as hedging instruments. The following table presents the notional amounts and fair values (determined using Level 2 inputs) of the Company’s derivatives as of September 30, 2019 and December 31, 2018 (in thousands): September 30, 2019 December 31, 2018 Balance Sheet Classification Notional amount Asset/(Liability) Notional amount Asset/(Liability) Derivatives in an asset position: Other assets $ — $ — $ 625,000 $ 3,318 Derivatives in a liability position: Other long-term liabilities 625,000 (3,805 ) — — $ 625,000 $ (3,805 ) $ 625,000 $ 3,318 The Company records the change in the fair value of derivatives designated as hedging instruments under ASC 815 to accumulated other comprehensive loss in the Company's consolidated condensed balance sheet, net of deferred taxes, and will later reclassify into earnings, including the associated tax impact, when the hedged item affects earnings or is no longer expected to occur. For other derivative contracts that do not qualify or no longer qualify for hedge accounting, changes in the fair value of the derivatives are recognized in earnings each period. The table below presents the effect of the Company's derivatives on the consolidated condensed statements of operations and comprehensive income for the three and nine months ended September 30, 2019 and 2018 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Derivatives in Cash Flow Hedging Relationships (Interest Rate Swaps) 2019 2018 2019 2018 Amount of pre-tax (loss) gain recognized in other comprehensive income $ (266 ) $ 1,422 $ (6,190 ) $ 7,617 Amount of loss reclassified from accumulated other comprehensive loss into interest expense, net (1,611 ) (1,463 ) (4,028 ) (4,980 ) The Company expects that $9.5 million of unrealized losses will be reclassified out of accumulated other comprehensive loss and into interest expense, net over the next 12 months. The effect of cash flow hedge accounting on the consolidated condensed statements of operations for the three and nine months ended September 30, 2019 and 2018 , respectively, is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Interest expense, net $ (12,974 ) $ (14,423 ) $ (37,834 ) $ (43,860 ) Loss on cash flow hedging relationships in Subtopic 815-20 (interest contracts): Loss reclassified from accumulated other comprehensive loss into interest expense, net (1,611 ) (1,463 ) (4,028 ) (4,980 )

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Below is a summary of the components of accumulated other comprehensive loss (in thousands): Foreign Currency Translation, Net of Tax Derivative Instruments, Net of Tax Total Balance at December 31, 2018 $ (158,349 ) $ (12,310 ) $ (170,659 ) Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income — 1,419 1,419 Balance at January 1, 2019 (158,349 ) (10,891 ) (169,240 ) Other comprehensive loss before reclassifications (26,768 ) (4,567 ) (31,335 ) Reclassification adjustments — 2,972 2,972 Balance at September 30, 2019 $ (185,117 ) $ (12,486 ) $ (197,603 ) Foreign Currency Translation The change in the Company's foreign currency translation adjustment was due primarily to the movements in the British pound, Euro, Canadian dollar and Russian ruble exchange rates against the U.S. dollar. The U.S. dollar strengthened by 3.4% and 4.6% versus the British pound and Euro, respectively, and weakened by 3.0% and 7.3% versus the Canadian dollar and the Russian ruble, respectively, between December 31, 2018 and September 30, 2019 . The movement in the Euro and British pound contributed to a $15.7 million and $7.4 million increase in other comprehensive loss, respectively, which was offset by decreases in other comprehensive loss of $1.6 million and $1.1 million due to movement in the Russian ruble and Canadian dollar, respectively, during the nine months ended September 30, 2019 . Derivative Instruments See "Note 12 - Derivatives" for further information on changes to accumulated other comprehensive loss related to the derivative instruments.

Net Income Per Share

Net Income Per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Net Income Per Share	Net Income Per Share Basic net income per share is calculated by dividing net income by the weighted average number of common shares outstanding for the applicable period. Diluted net income per share is calculated after adjusting the denominator of the basic net income per share calculation for the effect of all potentially dilutive common shares, which, in the Company’s case, includes shares issuable under the stock option and incentive award plans. The following table reconciles the basic to diluted weighted average shares outstanding (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Basic weighted average common shares outstanding 64,771 64,261 65,096 63,891 Effect of dilutive stock options and other awards under share-based compensation programs 1,442 2,245 1,511 2,367 Diluted weighted average common shares outstanding 66,213 66,506 66,607 66,258 Anti-dilutive shares 2,150 987 1,914 1,670 The dilutive and anti-dilutive shares disclosed above were calculated using the treasury stock method. The treasury stock method calculates dilution assuming the exercise of all in-the-money options and vesting of RSAs/RSUs, reduced by the repurchase of shares with the proceeds from the assumed exercises, and unrecognized compensation expense for outstanding awards.

Segments

Segments	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Segments	Segments The Company is managed through two reportable segments: (i) the Clinical Research segment and (ii) the Data Solutions segment. In accordance with the provisions of ASC 280, "Segment Reporting", the Company's chief operating decision-maker has been identified as the Chief Executive Officer, who reviews operating results to make decisions about allocating resources and assessing performance for the entire company. • Clinical Research Segment: The Clinical Research segment, which primarily serves biopharmaceutical clients, provides outsourced clinical research and clinical trial related services. • Data Solutions Segment: The Data Solutions segment provides data and analytics, technology solutions and real-world insights and services primarily to the Company’s life science customers. The Company's chief operating decision-maker uses segment profit as the primary measure of each segment's operating results in order to allocate resources and in assessing the Company's performance. Asset information by segment is not presented, as this measure is not used by the chief operating decision-maker to assess the Company's performance. The Company’s reportable segment information is presented below (in thousands): Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue $ 719,005 $ 61,686 $ 780,691 $ 656,979 $ 60,617 $ 717,596 Direct costs (exclusive of depreciation and amortization) 342,695 46,609 389,304 330,037 41,385 371,422 Reimbursable expenses 169,965 — 169,965 142,717 — 142,717 Segment profit 206,345 15,077 221,422 184,225 19,232 203,457 Less expenses not allocated to segments: Selling, general and administrative expenses 95,542 92,553 Transaction-related costs 572 43,837 Depreciation and amortization expense 29,264 28,270 Loss (gain) on disposal of fixed assets, net 256 (15 ) Income from operations 95,788 38,812 Interest expense, net (12,974 ) (14,423 ) Loss on modification or extinguishment of debt (1,855 ) (454 ) Foreign currency gains (losses), net 5,408 (1,809 ) Other income (expense), net 15 (68 ) Income before income taxes and equity in income of unconsolidated joint ventures $ 86,382 $ 22,058 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue $ 2,087,863 $ 178,159 $ 2,266,022 $ 1,966,762 $ 175,512 $ 2,142,274 Direct costs (exclusive of depreciation and amortization) 1,022,329 131,112 1,153,441 1,010,915 123,594 1,134,509 Reimbursable expenses 471,682 — 471,682 430,892 — 430,892 Segment profit 593,852 47,047 640,899 524,955 51,918 576,873 Less expenses not allocated to segments: Selling, general and administrative expenses 291,439 275,424 Transaction-related costs 572 32,709 Depreciation and amortization expense 85,462 84,163 Loss on disposal of fixed assets, net 900 21 Income from operations 262,526 184,556 Interest expense, net (37,834 ) (43,860 ) Loss on modification or extinguishment of debt (1,855 ) (454 ) Foreign currency gains (losses), net 1,864 (1,416 ) Other expense, net (66 ) (201 ) Income before income taxes and equity in income of unconsolidated joint ventures $ 224,635 $ 138,625 Revenue by geographic location for each segment is as follows (in thousands): Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue Americas: United States $ 467,096 $ 61,686 $ 528,782 $ 433,050 $ 60,617 $ 493,667 Other 12,255 — 12,255 11,396 — 11,396 Total Americas 479,351 61,686 541,037 444,446 60,617 505,063 Europe, Africa, and Asia-Pacific United Kingdom 191,994 — 191,994 170,252 — 170,252 Netherlands 30,144 — 30,144 28,334 — 28,334 Other 17,516 — 17,516 13,947 — 13,947 Total Europe, Africa, and Asia-Pacific 239,654 — 239,654 212,533 — 212,533 Total revenue $ 719,005 $ 61,686 $ 780,691 $ 656,979 $ 60,617 $ 717,596 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue Americas: United States $ 1,368,344 $ 178,159 $ 1,546,503 $ 1,284,678 $ 175,512 $ 1,460,190 Other 37,268 — 37,268 35,346 — 35,346 Total Americas 1,405,612 178,159 1,583,771 1,320,024 175,512 1,495,536 Europe, Africa, and Asia-Pacific United Kingdom 551,460 — 551,460 516,442 — 516,442 Netherlands 82,839 — 82,839 87,340 — 87,340 Other 47,952 — 47,952 42,956 — 42,956 Total Europe, Africa, and Asia-Pacific 682,251 — 682,251 646,738 — 646,738 Total revenue $ 2,087,863 $ 178,159 $ 2,266,022 $ 1,966,762 $ 175,512 $ 2,142,274

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On October 28, 2019, the Company refinanced its 2016 Credit Facilities. The Company entered into a new credit agreement with a syndicate of banks for an aggregate principal amount of $1,000.0 million of first lien term debt due in 2024, or the 2019 First Lien Term Loan, and a five-year $750.0 million revolving line of credit, collectively known as the 2019 Credit Facilities. The proceeds from the 2019 Credit Facilities were primarily used to repay the 2016 First Lien Term Loan principal balance of $1,191.5 million . The 2019 Credit Facilities also contain customary representations, warranties, affirmative covenants, and events of default. The variable interest rate is a rate equal to LIBOR or ABR, at the election of the Company, plus a margin based on the ratio of total indebtedness to EBITDA. The margin ranges from 1.0% to 2.0% , in the case of LIBOR loans, and 0.0% to 1.0% , in the case of ABR loans. The Company has the option of 1 , 2 , 3 or 6 month base interest rates. The 2019 First Lien Term Loan requires the Company to repay 2.5% of the original aggregate principal amount per annum in equal quarterly installments beginning on March 31, 2020 through September 30, 2024, with the remaining balance due at maturity.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Recently Implemented and Recently Issued Accounting Pronouncements	Recently Implemented Accounting Pronouncements On January 1, 2019, the Company adopted Accounting Standards Codification, or ASC, Topic 842, “Leases,” or ASC 842, using the revised modified retrospective approach provided by ASU No. 2018-11, “Leases (Topic 842): Targeted Improvements.” The revised modified retrospective approach recognizes the effects of initially applying the new leases standard as a cumulative effect adjustment to retained earnings as of the adoption date. Under this election, the provisions of ASC 840 apply to the accounting and disclosures for lease arrangements in the comparative periods in the Company's financial statements. The adoption of ASC 842 resulted in the recognition of lease liabilities of $211.7 million (recorded as $31.9 million in short-term lease liabilities and $179.8 million in long-term lease liabilities) and $187.1 million of lease right-of-use, or ROU, assets as of January 1, 2019. Upon adoption of ASC 842, the Company had lease obligations associated with deferred rent, lease loss liabilities, above market lease liabilities, and tenant improvement allowances, totaling $25.7 million , that were reclassified to the lease right-to-use assets. The Company had prepaid rent balances, totaling $1.1 million , that were reclassified as a reduction of the current portion of operating lease liabilities. The adoption of ASC 842 did not impact the consolidated condensed statement of operations for the nine months ended September 30, 2019 , consolidated condensed statement of cash flows, or earnings per share. See "Note 2 - Significant Accounting Policies" for further disclosures regarding the adoption of ASC 842. In August 2017, the Financial Accounting Standards Board, or FASB, issued ASU No. 2017-12, "Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities," in order to simplify certain aspects of hedge accounting and improve disclosures of hedging arrangements. ASU No. 2017-12 eliminates the need to separately measure and report hedge ineffectiveness and generally requires the entire change in fair value of a hedging instrument to be presented in the same income statement line as the hedged item. Entities must apply the amendments to cash flow and net investment hedge relationships that exist on the date of adoption using a modified retrospective approach. The presentation and disclosure requirements must be applied prospectively. The Company adopted this standard effective January 1, 2019 and the application of ASU No. 2017-12 did not have a material impact on the Company's consolidated condensed financial statements. In February 2018, the FASB issued ASU No. 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017, or the Act. The amendments in this update also require entities to disclose their accounting policy for releasing income tax effects from accumulated other comprehensive income. The Company adopted this standard effective January 1, 2019 and the application of ASU No. 2018-02 resulted in a reclassification of $1.4 million from accumulated other comprehensive loss to retained earnings for the stranded tax effects resulting from the Act. In October 2018, the FASB issued ASU No. 2018-16, "Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes," which amends ASC 815, Derivatives and Hedging. This ASU adds the OIS rate based on SOFR to the list of permissible benchmark rates for hedge accounting purposes. The Company adopted ASU No. 2018-16 concurrent with adoption of ASU No. 2017-12, on January 1, 2019, and the application of ASU No. 2018-16 did not have a material impact on the Company’s consolidated condensed financial statements. Recently Issued Accounting Pronouncements In January 2017, the FASB issued ASU No. 2017-04, “Intangibles-Goodwill and Other: Simplifying the Test for Goodwill Impairment,” in order to simplify the subsequent measurement of goodwill by eliminating the Step 2 goodwill impairment test. Under the amendments in this ASU, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity will then recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The guidance is effective for fiscal years beginning after December 15, 2019, with early adoption permitted. The adoption of ASU No. 2017-04 is not expected to have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-15, "Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract," in order to expand on the FASB's guidance of capitalized costs incurred in a cloud computing arrangement. The amendments in this update require an entity (customer) in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which implementation costs to capitalize as an asset related to the service contract and which costs to expense. The guidance is effective for the reporting period beginning after December 15, 2019, and interim periods therein, with early adoption permitted. The adoption of ASU No. 2018-15 is not expected to have a material impact on the Company's consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” The provisions of ASU 2016-13 modify the impairment model to utilize an expected loss methodology in place of the currently used incurred loss methodology and require consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The guidance is effective for the reporting period beginning after December 15, 2019, and the interim periods therein. The adoption of ASU 2016-13 is not expected to have a material impact on the Company’s consolidated financial statements. On January 1, 2019, the Company adopted ASC 842 using the revised modified retrospective approach. The revised modified retrospective approach recognizes the effects of initially applying the new leases standard as a cumulative effect adjustment to retained earnings as of the adoption date. Under this election, the provisions of ASC 840 apply to the accounting and disclosures for lease arrangements in the comparative periods in an entity’s financial statements. In addition, the Company elected the package of practical expedients permitted under the transition guidance within ASC 842, in which the Company need not reassess (i) the historical lease classification, (ii) whether any expired or existing contract is or contains a lease, or (iii) the initial direct costs for any existing leases. The Company’s material lease obligations are operating leases for office and other facilities in which the Company conducts business. The facility leases generally provide an initial lease term ranging from three to 20 years and include one or more optional extensions. The Company's leases have remaining lease terms of one year to 17 years . The leases typically include rent escalation clauses and for some markets the leases frequently include periodic market adjustments to the base rent over the term of the lease. In certain instances, the Company subleases space that has been exited or is no longer required. The Company’s sublease income is immaterial. Upon the initial application of ASC 842 on January 1, 2019, or the transition date, lease liabilities were measured by using the remaining minimum rental payments under ASC 840. The Company’s ASC 840 minimum rental payments include executory costs and rental payments that depend on an index or rate are calculated based on the rate in effect at the transition date. The lease liability is measured at the present value of future lease payments, discounted using the discount rate as of the transition date. In addition to recognizing the lease liability, the Company recognized a corresponding asset representing its right to use the underlying asset over the lease term, referred to as the lease ROU asset. The ROU asset is initially measured as the amount of lease liability, adjusted for any initial lease costs or lease payments made before or at the commencement of the lease, and reduced by any lease incentives and deferred rent. As of the transition date, the Company’s leases consisted of only operating leases and upon recognition of the lease liability and ROU assets, there was no adjustment to retained earnings. All leases entered into after January 1, 2019 are accounted for under ASC 842. Under ASC 842, a contract is or contains a lease when (i) explicitly or implicitly identified assets have been deployed in the contract and (ii) the customer obtains substantially all of the economic benefits from the use of that underlying asset and directs how and for what purpose the asset is used during the term of the contract. The Company also considers whether its service arrangements include the right to control the use of an asset. The Company determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The commencement date of the lease is the date that the lessor makes an underlying asset available for use by a lessee. At the lease commencement date, a lease liability is recognized based on the present value of the lease payments not yet paid, discounted using the discount rate for the lease at lease commencement. When readily determinable, the discount rate used to calculate the lease liability is the rate implicit in the lease. As the Company's leases typically do not provide an implicit rate, the Company uses its incremental borrowing rate based on the lease term and economic environment at the lease commencement date. The lease term used to calculate the lease liability includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. With limited exceptions, the nature of the Company's facility leases is such that there are not economic or other conditions that would indicate that it is reasonably certain at lease commencement that the Company will exercise options to extend the term. The Company determines if its lease obligations are operating or finance leases at the lease commencement date and considers whether the lease grants an option to purchase the underlying asset that it is reasonably certain to exercise, the remaining economic life of the underlying asset, the present value of the sum of the remaining lease payments and any residual value guaranteed, and the nature of the asset. The initial measurement of the lease liability is determined based on the future lease payments, which may include lease payments that depend on an index or a rate (such as the consumer price index or other market index). The Company initially measures payments based on an index or rate by using the applicable rate at lease commencement and subsequent changes in such rates are recognized as variable lease costs. Variable payments that do not depend on a rate or index are not included in the lease liability and are recognized as they are incurred. The Company’s contracts that include a lease component generally include additional services that are transferred to the lessee (e.g., common-area maintenance services), which are nonlease components. Contracts typically also include other costs and fees that do not provide a separate service to the lessee, such as costs paid by the lessee to reimburse the lessor for administrative costs or payment for the lessor’s costs for property taxes, insurance related to the leased asset, and other lessor costs. The Company elected the practical expedient to account for the lease and nonlease components as a single lease component. At the lease commencement date, the Company recognizes a ROU asset representing its right to use the underlying asset over the lease term. If significant events, changes in circumstances, or other events indicate that the lease term has changed, the Company would reassess lease classification, remeasure the lease liability by using revised inputs as of the reassessment date, and adjust the ROU asset. These reassessment events are typically related to the exercise of optional renewals or significant new investments in leasehold improvements. The costs of services and costs related to reimbursements of the lessor’s cost are generally variable rent obligations, which are excluded from the future lease payments included in the lease liability. For leases with a term of one year or less, or short-term leases, the Company has elected to not recognize the lease liability for these arrangements and the lease payments are recognized in the consolidated statement of operations on a straight-line basis over the lease term. The total expense for the operating lease liability is recognized on a straight-line basis over the lease term, beginning on the lease commencement date. The Company classifies the lease costs within operating expenses consistent with the classification policies for all other operating costs.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash The Company receives cash advances from its customers to be used for the payment of investigator fees and other pass-through expenses. The terms of certain customer contracts require that such advances be maintained in separate escrow accounts; thus, these accounts are not commingled with the Company’s cash and cash equivalents. These accounts are presented separately in the consolidated condensed balance sheets as restricted cash.
Leases Liabilities	All leases entered into after January 1, 2019 are accounted for under ASC 842. Under ASC 842, a contract is or contains a lease when (i) explicitly or implicitly identified assets have been deployed in the contract and (ii) the customer obtains substantially all of the economic benefits from the use of that underlying asset and directs how and for what purpose the asset is used during the term of the contract. The Company also considers whether its service arrangements include the right to control the use of an asset. The Company determines if an arrangement is a lease at inception of the contract, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The commencement date of the lease is the date that the lessor makes an underlying asset available for use by a lessee. At the lease commencement date, a lease liability is recognized based on the present value of the lease payments not yet paid, discounted using the discount rate for the lease at lease commencement. When readily determinable, the discount rate used to calculate the lease liability is the rate implicit in the lease. As the Company's leases typically do not provide an implicit rate, the Company uses its incremental borrowing rate based on the lease term and economic environment at the lease commencement date. The lease term used to calculate the lease liability includes options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. With limited exceptions, the nature of the Company's facility leases is such that there are not economic or other conditions that would indicate that it is reasonably certain at lease commencement that the Company will exercise options to extend the term. The Company determines if its lease obligations are operating or finance leases at the lease commencement date and considers whether the lease grants an option to purchase the underlying asset that it is reasonably certain to exercise, the remaining economic life of the underlying asset, the present value of the sum of the remaining lease payments and any residual value guaranteed, and the nature of the asset. The initial measurement of the lease liability is determined based on the future lease payments, which may include lease payments that depend on an index or a rate (such as the consumer price index or other market index). The Company initially measures payments based on an index or rate by using the applicable rate at lease commencement and subsequent changes in such rates are recognized as variable lease costs. Variable payments that do not depend on a rate or index are not included in the lease liability and are recognized as they are incurred. The Company’s contracts that include a lease component generally include additional services that are transferred to the lessee (e.g., common-area maintenance services), which are nonlease components. Contracts typically also include other costs and fees that do not provide a separate service to the lessee, such as costs paid by the lessee to reimburse the lessor for administrative costs or payment for the lessor’s costs for property taxes, insurance related to the leased asset, and other lessor costs. The Company elected the practical expedient to account for the lease and nonlease components as a single lease component. At the lease commencement date, the Company recognizes a ROU asset representing its right to use the underlying asset over the lease term. If significant events, changes in circumstances, or other events indicate that the lease term has changed, the Company would reassess lease classification, remeasure the lease liability by using revised inputs as of the reassessment date, and adjust the ROU asset. These reassessment events are typically related to the exercise of optional renewals or significant new investments in leasehold improvements. The costs of services and costs related to reimbursements of the lessor’s cost are generally variable rent obligations, which are excluded from the future lease payments included in the lease liability. For leases with a term of one year or less, or short-term leases, the Company has elected to not recognize the lease liability for these arrangements and the lease payments are recognized in the consolidated statement of operations on a straight-line basis over the lease term. The total expense for the operating lease liability is recognized on a straight-line basis over the lease term, beginning on the lease commencement date. The Company classifies the lease costs within operating expenses consistent with the classification policies for all other operating costs.
Fair Value Measurements	The Company records certain assets and liabilities at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. A three-level fair value hierarchy that prioritizes the inputs used to measure fair value is described below. This hierarchy requires entities to maximize the use of observable inputs and minimize the use of unobservable inputs. The three levels of inputs used to measure fair value are as follows: • Level 1 — Quoted prices in active markets for identical assets or liabilities. • Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data. • Level 3 — Unobservable inputs that are supported by little or no market activity. This includes certain pricing models, discounted cash flow methodologies and similar techniques that use significant unobservable inputs.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Reconciliation of cash, cash equivalents, and restricted cash reported	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated condensed balance sheets that sum to the total of the same amounts shown in the consolidated condensed statements of cash flows (in thousands): September 30, December 31, 2019 2018 2018 2017 Cash and cash equivalents $ 181,767 $ 127,517 $ 144,221 $ 192,229 Restricted cash 23 318 488 661 Total cash, cash equivalents, and restricted cash $ 181,790 $ 127,835 $ 144,709 $ 192,890

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Components of lease expense	Supplemental balance sheet information related to leases was as follows as of September 30, 2019 : As of September 30, 2019 Weighted average remaining lease term 8.0 years Weighted average discount rate 4.3% The components of lease expense were as follows for the three and nine months ended September 30, 2019 (in thousands): Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Lease cost: Operating lease cost $ 9,788 $ 28,583 Short-term lease cost 725 2,033 Variable lease cost 2,175 5,796 Lease income (47 ) (130 ) Net lease cost $ 12,641 $ 36,282
Summary of supplemental cash flow information	Supplemental cash flow information related to leases was as follows for the three and nine months ended September 30, 2019 (in thousands): Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 Cash paid for amounts included in the measurements of lease liabilities, all included in operating cash flows $ 9,772 $ 28,262 Right-of-use assets obtained in exchange for lease obligations 5,100 26,148
Schedule of maturities of lease liabilities	Maturities of operating lease liabilities were as follows as of September 30, 2019 (in thousands): 2019 (remaining) $ 9,192 2020 42,946 2021 39,210 2022 31,454 2023 25,891 Thereafter 93,864 Total lease payments 242,557 Less imputed interest (38,153 ) Total $ 204,404
Schedule of future non-cancelable rent obligations as determined under ASC 840	As of December 31, 2018 , the Company disclosed the following future non-cancelable rent obligations as determined under ASC 840 (in thousands): 2019 $ 43,675 2020 40,948 2021 37,469 2022 30,238 2023 24,235 Thereafter 90,978 Total lease payments $ 267,543

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Summary of the fair value of financial assets and liabilities measured on a recurring basis	The following table summarizes the fair value of the Company’s financial liabilities that are measured on a recurring basis as of September 30, 2019 (in thousands): Level 1 Level 2 Level 3 Total Liabilities: Interest rate swaps $ — $ 3,805 $ — $ 3,805 Total $ — $ 3,805 $ — $ 3,805

Concentration of Credit Risk (T

Concentration of Credit Risk (Tables)	9 Months Ended
	Sep. 30, 2019
Risks and Uncertainties [Abstract]
Schedule of concentration of risk by risk factor	Accounts receivable and unbilled services from individual customers that were equal to or greater than 10% of consolidated accounts receivable and unbilled services at the respective dates were as follows: September 30, December 31, 2019 2018 Customer A 10.6 % 12.2 % Customer B 15.5 % 11.4 %

Accounts Receivable, Unbilled_2

Accounts Receivable, Unbilled Services and Advanced Billings (Tables)	9 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Schedule of accounts receivable and unbilled services	Accounts receivable and unbilled services were as follows (in thousands): September 30, December 31, 2019 2018 Accounts receivable $ 557,077 $ 437,001 Unbilled services 147,952 133,147 Total accounts receivable and unbilled services 705,029 570,148 Less allowance for doubtful accounts (2,393 ) (2,049 ) Total accounts receivable and unbilled services, net $ 702,636 $ 568,099
Schedule of advanced billings	Advanced billings were as follows (in thousands): September 30, December 31, 2019 2018 Advanced billings $ 474,999 $ 441,357

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in the carrying amount of goodwill	The changes in the carrying amount of goodwill by reportable segment are as follows (in thousands): Clinical Research Data Solutions Consolidated Balance at December 31, 2018 $ 1,017,903 $ 476,859 $ 1,494,762 Currency translation (10,256 ) — (10,256 ) Balance at September 30, 2019 $ 1,007,647 $ 476,859 $ 1,484,506
Schedule of intangible assets	Intangible assets consist of the following (in thousands): September 30, 2019 December 31, 2018 Gross Amount Accumulated Amortization Net Amount Gross Amount Accumulated Amortization Net Amount Customer relationships $ 551,020 $ (127,070 ) $ 423,950 $ 555,915 $ (103,248 ) $ 452,667 Trade names (finite-lived) 28,524 (15,636 ) 12,888 28,505 (12,810 ) 15,695 Patient list and other intangibles 44,474 (34,476 ) 9,998 44,474 (30,939 ) 13,535 Database 137,100 (52,651 ) 84,449 137,100 (32,561 ) 104,539 Total finite-lived intangible assets 761,118 (229,833 ) 531,285 765,994 (179,558 ) 586,436 Trade names (indefinite-lived) 118,010 — 118,010 118,010 — 118,010 Total intangible assets $ 879,128 $ (229,833 ) $ 649,295 $ 884,004 $ (179,558 ) $ 704,446
Schedule of estimated future amortization expense	The estimated future amortization expense of finite-lived intangible assets is expected to be as follows (in thousands): 2019 (remaining) $ 17,079 2020 68,711 2021 63,619 2022 49,244 2023 37,515 2024 and thereafter 295,117 Total $ 531,285

Revolving Credit Facilities a_2

Revolving Credit Facilities and Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Schedule of long-term debt	Long-term debt consists of the following (in thousands): September 30, December 31, 2019 2018 Term loans, first lien $ 1,191,533 $ 916,533 Accounts receivable financing agreement 200,000 170,000 Total debt 1,391,533 1,086,533 Less current portion of long-term debt — — Total long-term debt 1,391,533 1,086,533 Less debt issuance costs (3,138 ) (4,149 ) Total long-term debt, net $ 1,388,395 $ 1,082,384
Schedule of principal payments on long-term debt due	Principal payments on long-term debt are due as follows (in thousands): Current maturities of long-term debt: 2019 (remaining) $ — 2020 — 2021 1,391,533 2022 — Total $ 1,391,533

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Stockholders' Equity Note [Abstract]
Summary of noncontrolling interest	Below is a summary of noncontrolling interest for the nine months ended September 30 (in thousands): 2019 2018 Balance as of January 1, $ 6,390 $ 5,710 Comprehensive income Net income 99 898 Foreign currency adjustments, net of income tax 76 (75 ) Acquisition of noncontrolling interest (6,565 ) — Balance as of September 30, $ — $ 6,533

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based Payment Arrangement [Abstract]
Summary of stock option activity	Aggregated information regarding the Company’s option plans is summarized below: Options Wtd. Average Exercise Price Wtd. Average Remaining Contractual Life (in years) Intrinsic Value (millions) Outstanding at December 31, 2018 4,641,600 $ 62.29 7.8 $ 149.7 Granted 1,150,000 98.42 Exercised (464,564 ) 33.86 Expired or forfeited (199,550 ) 82.92 Outstanding at September 30, 2019 5,127,486 $ 72.17 7.7 $ 144.8 Exercisable at September 30, 2019 1,975,811 $ 42.71 6.0 $ 112.5
Schedule of RSA/RSU activity	The Company’s RSAs/RSUs activity in 2019 is as follows: Awards Wtd. Average Grant-Date Fair Value Intrinsic Value (millions) Unvested December 31, 2018 344,250 $ 81.39 $ 31.7 Granted 352,036 97.06 Forfeited (40,500 ) 80.72 Vested (22,750 ) 61.57 Unvested September 30, 2019 633,036 $ 90.87 $ 62.8
Schedule of stock-based compensation expense	Stock-based compensation expense related to employee stock plans are summarized below (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Direct costs $ 3,685 $ 2,451 $ 9,780 $ 6,900 Selling, general and administrative 7,559 5,319 20,627 13,569 Transaction-related costs — 773 — 773 Total stock-based compensation expense $ 11,244 $ 8,543 $ 30,407 $ 21,242

Derivatives (Tables)

Derivatives (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of notional amounts and fair values (determined using level 2 inputs) of derivatives	The following table presents the notional amounts and fair values (determined using Level 2 inputs) of the Company’s derivatives as of September 30, 2019 and December 31, 2018 (in thousands): September 30, 2019 December 31, 2018 Balance Sheet Classification Notional amount Asset/(Liability) Notional amount Asset/(Liability) Derivatives in an asset position: Other assets $ — $ — $ 625,000 $ 3,318 Derivatives in a liability position: Other long-term liabilities 625,000 (3,805 ) — — $ 625,000 $ (3,805 ) $ 625,000 $ 3,318
Schedule of the effect of derivatives on the condensed consolidated statements of operations and comprehensive (loss) income	The effect of cash flow hedge accounting on the consolidated condensed statements of operations for the three and nine months ended September 30, 2019 and 2018 , respectively, is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Interest expense, net $ (12,974 ) $ (14,423 ) $ (37,834 ) $ (43,860 ) Loss on cash flow hedging relationships in Subtopic 815-20 (interest contracts): Loss reclassified from accumulated other comprehensive loss into interest expense, net (1,611 ) (1,463 ) (4,028 ) (4,980 ) The table below presents the effect of the Company's derivatives on the consolidated condensed statements of operations and comprehensive income for the three and nine months ended September 30, 2019 and 2018 (in thousands): Three Months Ended September 30, Nine Months Ended September 30, Derivatives in Cash Flow Hedging Relationships (Interest Rate Swaps) 2019 2018 2019 2018 Amount of pre-tax (loss) gain recognized in other comprehensive income $ (266 ) $ 1,422 $ (6,190 ) $ 7,617 Amount of loss reclassified from accumulated other comprehensive loss into interest expense, net (1,611 ) (1,463 ) (4,028 ) (4,980 )

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Summary of components of accumulated other comprehensive loss	Below is a summary of the components of accumulated other comprehensive loss (in thousands): Foreign Currency Translation, Net of Tax Derivative Instruments, Net of Tax Total Balance at December 31, 2018 $ (158,349 ) $ (12,310 ) $ (170,659 ) Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income — 1,419 1,419 Balance at January 1, 2019 (158,349 ) (10,891 ) (169,240 ) Other comprehensive loss before reclassifications (26,768 ) (4,567 ) (31,335 ) Reclassification adjustments — 2,972 2,972 Balance at September 30, 2019 $ (185,117 ) $ (12,486 ) $ (197,603 )

Net Income Per Share (Tables)

Net Income Per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of weighted average basic and diluted common shares	The following table reconciles the basic to diluted weighted average shares outstanding (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Basic weighted average common shares outstanding 64,771 64,261 65,096 63,891 Effect of dilutive stock options and other awards under share-based compensation programs 1,442 2,245 1,511 2,367 Diluted weighted average common shares outstanding 66,213 66,506 66,607 66,258 Anti-dilutive shares 2,150 987 1,914 1,670

Segments (Tables)

Segments (Tables)	9 Months Ended
	Sep. 30, 2019
Segment Reporting [Abstract]
Schedule of segment reporting information	The Company’s reportable segment information is presented below (in thousands): Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue $ 719,005 $ 61,686 $ 780,691 $ 656,979 $ 60,617 $ 717,596 Direct costs (exclusive of depreciation and amortization) 342,695 46,609 389,304 330,037 41,385 371,422 Reimbursable expenses 169,965 — 169,965 142,717 — 142,717 Segment profit 206,345 15,077 221,422 184,225 19,232 203,457 Less expenses not allocated to segments: Selling, general and administrative expenses 95,542 92,553 Transaction-related costs 572 43,837 Depreciation and amortization expense 29,264 28,270 Loss (gain) on disposal of fixed assets, net 256 (15 ) Income from operations 95,788 38,812 Interest expense, net (12,974 ) (14,423 ) Loss on modification or extinguishment of debt (1,855 ) (454 ) Foreign currency gains (losses), net 5,408 (1,809 ) Other income (expense), net 15 (68 ) Income before income taxes and equity in income of unconsolidated joint ventures $ 86,382 $ 22,058 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue $ 2,087,863 $ 178,159 $ 2,266,022 $ 1,966,762 $ 175,512 $ 2,142,274 Direct costs (exclusive of depreciation and amortization) 1,022,329 131,112 1,153,441 1,010,915 123,594 1,134,509 Reimbursable expenses 471,682 — 471,682 430,892 — 430,892 Segment profit 593,852 47,047 640,899 524,955 51,918 576,873 Less expenses not allocated to segments: Selling, general and administrative expenses 291,439 275,424 Transaction-related costs 572 32,709 Depreciation and amortization expense 85,462 84,163 Loss on disposal of fixed assets, net 900 21 Income from operations 262,526 184,556 Interest expense, net (37,834 ) (43,860 ) Loss on modification or extinguishment of debt (1,855 ) (454 ) Foreign currency gains (losses), net 1,864 (1,416 ) Other expense, net (66 ) (201 ) Income before income taxes and equity in income of unconsolidated joint ventures $ 224,635 $ 138,625
Schedule of segment revenue by geographic location	Revenue by geographic location for each segment is as follows (in thousands): Three Months Ended September 30, 2019 Three Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue Americas: United States $ 467,096 $ 61,686 $ 528,782 $ 433,050 $ 60,617 $ 493,667 Other 12,255 — 12,255 11,396 — 11,396 Total Americas 479,351 61,686 541,037 444,446 60,617 505,063 Europe, Africa, and Asia-Pacific United Kingdom 191,994 — 191,994 170,252 — 170,252 Netherlands 30,144 — 30,144 28,334 — 28,334 Other 17,516 — 17,516 13,947 — 13,947 Total Europe, Africa, and Asia-Pacific 239,654 — 239,654 212,533 — 212,533 Total revenue $ 719,005 $ 61,686 $ 780,691 $ 656,979 $ 60,617 $ 717,596 Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018 Clinical Research Data Solutions Total Clinical Research Data Solutions Total Revenue Americas: United States $ 1,368,344 $ 178,159 $ 1,546,503 $ 1,284,678 $ 175,512 $ 1,460,190 Other 37,268 — 37,268 35,346 — 35,346 Total Americas 1,405,612 178,159 1,583,771 1,320,024 175,512 1,495,536 Europe, Africa, and Asia-Pacific United Kingdom 551,460 — 551,460 516,442 — 516,442 Netherlands 82,839 — 82,839 87,340 — 87,340 Other 47,952 — 47,952 42,956 — 42,956 Total Europe, Africa, and Asia-Pacific 682,251 — 682,251 646,738 — 646,738 Total revenue $ 2,087,863 $ 178,159 $ 2,266,022 $ 1,966,762 $ 175,512 $ 2,142,274

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Recently Implemented Accounting Pronouncements
Operating lease liability	$ 204,404
Current lease liabilities	34,708		$ 0
Non-current lease liabilities	169,696		0
Lease right-of-use assets, net	$ 181,813		0
Accounting Standards Update 2016-02
Recently Implemented Accounting Pronouncements
Operating lease liability		$ 211,700
Current lease liabilities		31,900
Non-current lease liabilities		179,800
Lease right-of-use assets, net		187,100
Lease obligations			25,700
Prepaid rent			$ 1,100
Accounting Standards Update 2018-02
Recently Implemented Accounting Pronouncements
Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income		0
Accumulated Other Comprehensive Loss (Note 13)
Recently Implemented Accounting Pronouncements
Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income		1,419
Accumulated Other Comprehensive Loss (Note 13) | Accounting Standards Update 2018-02
Recently Implemented Accounting Pronouncements
Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income		$ 1,419

Basis of Presentation - Schedul

Basis of Presentation - Schedule of Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 181,767	$ 144,221	$ 127,517	$ 192,229
Restricted cash	23	488	318	661
Total cash, cash equivalents, and restricted cash	$ 181,790	$ 144,709	$ 127,835	$ 192,890

Significant Accounting Polici_4

Significant Accounting Policies - Additional Information (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Operating lease not yet commenced	$ 0.5
Operating lease not yet commenced, term of contract	2 years
Minimum
Lessee, Lease, Description [Line Items]
Operating lease, initial term of contract	3 years
Operating lease, remaining term of contract	1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease, initial term of contract	20 years
Operating lease, remaining term of contract	17 years

Significant Accounting Polici_5

Significant Accounting Policies - Components of lease (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Lease cost:
Operating lease cost	$ 9,788	$ 28,583
Short-term lease cost	725	2,033
Variable lease cost	2,175	5,796
Lease income	(47)	(130)
Net lease cost	$ 12,641	$ 36,282
Weighted average remaining lease term	8 years	8 years
Weighted average discount rate	4.30%	4.30%

Significant Accounting Polici_6

Significant Accounting Policies - Summary of supplemental cash flow information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Accounting Policies [Abstract]
Cash paid for amounts included in the measurements of lease liabilities, all included in operating cash flows	$ 9,772	$ 28,262
Right-of-use assets obtained in exchange for lease obligations	$ 5,100	$ 26,148

Significant Accounting Polici_7

Significant Accounting Policies - Schedule of maturities of lease liabilities (Details) $ in Thousands	Sep. 30, 2019USD ($)
Accounting Policies [Abstract]
2019 (remaining)	$ 9,192
2020	42,946
2021	39,210
2022	31,454
2023	25,891
Thereafter	93,864
Total lease payments	242,557
Less imputed interest	(38,153)
Total	$ 204,404

Significant Accounting Polici_8

Significant Accounting Policies - Schedule of future non-cancelable rent obligations as determined under ASC 840 (Details) $ in Thousands	Dec. 31, 2018USD ($)
Accounting Policies [Abstract]
2019	$ 43,675
2020	40,948
2021	37,469
2022	30,238
2023	24,235
Thereafter	90,978
Total lease payments	$ 267,543

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Financial Assets and Liabilities Measured on a Recurring Basis (Details) - Recurring $ in Thousands	Sep. 30, 2019USD ($)
Liabilities:
Liabilities fair value	$ 3,805
Interest rate swap
Liabilities:
Liabilities fair value	3,805
Level 1
Liabilities:
Liabilities fair value	0
Level 1 | Interest rate swap
Liabilities:
Liabilities fair value	0
Level 2
Liabilities:
Liabilities fair value	3,805
Level 2 | Interest rate swap
Liabilities:
Liabilities fair value	3,805
Level 3
Liabilities:
Liabilities fair value	0
Level 3 | Interest rate swap
Liabilities:
Liabilities fair value	$ 0

Fair Value Measurements - Non-r

Fair Value Measurements - Non-recurring Fair Value Measurements (Details) - Nonrecurring - Level 3 $ in Millions	Sep. 30, 2019USD ($)
Assets fair value measurements
Assets fair value	$ 2,133.8
Goodwill	1,484.5
Identifiable intangible assets	$ 649.3

Concentration of Credit Risk (D

Concentration of Credit Risk (Details) - Customer Concentration Risk - Accounts receivable and unbilled receivables	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Customer A
Concentration risk
Concentration risk percentage	10.60%	12.20%
Customer B
Concentration risk
Concentration risk percentage	15.50%	11.40%

Accounts Receivable, Unbilled_3

Accounts Receivable, Unbilled Services and Advanced Billings - Schedules (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Receivables [Abstract]
Accounts receivable	$ 557,077	$ 437,001
Unbilled services	147,952	133,147
Total accounts receivable and unbilled services	705,029	570,148
Less allowance for doubtful accounts	(2,393)	(2,049)
Total accounts receivable and unbilled services, net	702,636	568,099
Advanced billings	$ 474,999	$ 441,357

Accounts Receivable, Unbilled_4

Accounts Receivable, Unbilled Services and Advanced Billings - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contract with customer, asset, not past due	$ 75,100		$ 75,100		$ 66,600
Contract asset impairment losses	0	$ 0	0	$ 0
Advanced billings	474,999		474,999		$ 441,357
Revenue related to contract liabilities			398,400	382,500
Performance obligation satisfied in previous period	14,800	$ 24,400	$ 65,200	$ 57,300
Performance obligation, description of timing			The Company does not disclose the value of the transaction price allocated to unsatisfied performance obligations on contracts that have an original contract term of less than one year.
Accounting Standards Update 2014-09 | Reclassification from adoption of ASC 606
Accounts, Notes, Loans and Financing Receivable [Line Items]
Advanced billings	$ 33,600		$ 33,600

Accounts Receivable, Unbilled_5

Accounts Receivable, Unbilled Services and Advanced Billings - Performance Obligations (Details) $ in Billions	Sep. 30, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Accounts, Notes, Loans and Financing Receivable [Line Items]
Remaining performance obligation, amount	$ 5.2
Minimum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Accounts, Notes, Loans and Financing Receivable [Line Items]
Remaining performance obligation, expected timing of satisfaction, period	1 year
Maximum | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Accounts, Notes, Loans and Financing Receivable [Line Items]
Remaining performance obligation, expected timing of satisfaction, period	5 years

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Schedule of Changes in the Carrying Amount of Goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Changes in carrying amount of goodwill
Balance at beginning of period	$ 1,494,762
Currency translation	(10,256)
Balance at end of period	1,484,506
Clinical Research
Changes in carrying amount of goodwill
Balance at beginning of period	1,017,903
Currency translation	(10,256)
Balance at end of period	1,007,647
Data Solutions
Changes in carrying amount of goodwill
Balance at beginning of period	476,859
Currency translation	0
Balance at end of period	$ 476,859

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Accumulated impairment charges	$ 0		$ 0		$ 0
Amortization expense	$ 17,100,000	$ 17,900,000	$ 51,400,000	$ 54,000,000

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Goodwill And Intangible Assets
Total finite-lived intangible assets, gross	$ 761,118	$ 765,994
Accumulated Amortization	(229,833)	(179,558)
Net Amount	531,285	586,436
Trade names (indefinite-lived)	118,010	118,010
Total intangible assets, gross	879,128	884,004
Total intangible assets, net	649,295	704,446
Customer relationships
Goodwill And Intangible Assets
Total finite-lived intangible assets, gross	551,020	555,915
Accumulated Amortization	(127,070)	(103,248)
Net Amount	423,950	452,667
Trade names (finite-lived)
Goodwill And Intangible Assets
Total finite-lived intangible assets, gross	28,524	28,505
Accumulated Amortization	(15,636)	(12,810)
Net Amount	12,888	15,695
Patient list and other intangibles
Goodwill And Intangible Assets
Total finite-lived intangible assets, gross	44,474	44,474
Accumulated Amortization	(34,476)	(30,939)
Net Amount	9,998	13,535
Database
Goodwill And Intangible Assets
Total finite-lived intangible assets, gross	137,100	137,100
Accumulated Amortization	(52,651)	(32,561)
Net Amount	$ 84,449	$ 104,539

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Schedule of Estimated Future Amortization Expense of Finite-lived Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets, Amortization Expense, Maturity Schedule [Abstract]
2019 (remaining)	$ 17,079
2020	68,711
2021	63,619
2022	49,244
2023	37,515
2024 and thereafter	295,117
Net Amount	$ 531,285	$ 586,436

Revolving Credit Facilities a_3

Revolving Credit Facilities and Long-Term Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Long-term debt
Total debt	$ 1,391,533	$ 1,086,533
Less current portion of long-term debt	0	0
Total long-term debt	1,391,533	1,086,533
Less debt issuance costs	(3,138)	(4,149)
Long-term debt, net	1,388,395	1,082,384
Term loans, first lien
Long-term debt
Total debt	1,191,533	916,533
Accounts receivable financing agreement
Long-term debt
Total debt	$ 200,000	$ 170,000

Revolving Credit Facilities a_4

Revolving Credit Facilities and Long-Term Debt - Schedule of Future Principal Payments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current maturities of long-term debt:
2019 (remaining)	$ 0
2020	0
2021	1,391,533
2022	0
Total debt	$ 1,391,533	$ 1,086,533

Revolving Credit Facilities a_5

Revolving Credit Facilities and Long-Term Debt - 2016 Credit Facilities and Revolver (Details) - USD ($)	Sep. 03, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Long-term debt
Outstanding borrowings	$ 300,000,000
Loss on modification or extinguishment of debt	$ 1,900,000	$ 1,855,000	$ 454,000	$ 1,855,000	$ 454,000
Credit Facilities
Long-term debt
Interest period, option one				1 month
Interest period, option two				2 months
Interest period, option three				3 months
Interest period, option four				6 months
Weighted average interest rate		3.75%		3.75%
Credit Facilities | LIBOR | Minimum
Long-term debt
Applicable margin on variable rate basis				1.00%
Credit Facilities | LIBOR | Maximum
Long-term debt
Applicable margin on variable rate basis				2.00%
Credit Facilities | ABR | Minimum
Long-term debt
Applicable margin on variable rate basis				0.00%
Credit Facilities | ABR | Maximum
Long-term debt
Applicable margin on variable rate basis				1.00%
Revolving Credit Facility | Credit Facilities
Long-term debt
Interest period, option one				1 month
Interest period, option two				2 months
Interest period, option three				3 months
Interest period, option four				6 months
Outstanding borrowings		$ 0		$ 0		$ 0
Maximum borrowing capacity		225,000,000		225,000,000
Outstanding letters of credit		$ 5,200,000		$ 5,200,000		$ 5,400,000
Revolving Credit Facility | Credit Facilities | Minimum
Long-term debt
Commitment fee				0.20%
Revolving Credit Facility | Credit Facilities | Maximum
Long-term debt
Commitment fee				0.40%
Revolving Credit Facility | Credit Facilities | LIBOR | Minimum
Long-term debt
Variable base rate minimum floor				0.00%

Revolving Credit Facilities a_6

Revolving Credit Facilities and Long-Term Debt - Accounts Receivable Financing Agreement and Fair Value of Debt (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 03, 2019	Dec. 31, 2018
Long-term debt
Outstanding borrowings		$ 300,000,000
Fair Value of Debt
Estimated fair value of long-term debt	$ 1,390,000,000		$ 1,084,200,000
Accounts receivable financing agreement
Long-term debt
Outstanding borrowings	$ 200,000,000		170,000,000
Notice period for prepayment of loans	1 day
Notice period required for termination of agreement	15 days
Weighted average interest rate	3.86%
Remaining borrowing capacity	$ 0		$ 30,000,000
Accounts receivable financing agreement | LIBOR
Long-term debt
Applicable margin on variable rate basis	1.25%

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($)	Sep. 06, 2019	May 31, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Aug. 30, 2019	Dec. 31, 2018
Stockholders' Equity Note [Abstract]
Common stock, shares authorized			1,000,000,000	1,000,000,000			1,000,000,000
Common stock, par value (in dollars per share)			$ 0.01	$ 0.01			$ 0.01
Preferred stock, shares authorized			100,000,000	100,000,000			100,000,000
Preferred stock, par value (in dollars per share)			$ 0.01	$ 0.01			$ 0.01
Share Repurchase Program, authorized amount						$ 500,000,000
Secondary public offering, number of shares issued	6,666,684
Number of common stock shares repurchased and retired	3,079,765
Purchase price (in dollars per share)	$ 97.41
Purchase price of common stock repurchased	$ 300,000,000			$ 300,000,000	$ 0
Secondary public offering, expenses			$ 600,000	600,000
Share Repurchase Program, remaining authorized amount			$ 200,000,000	200,000,000
Acquisition of joint venture		$ 4,100,000		$ 4,138,000	$ 0

Stockholders' Equity - Noncontr

Stockholders' Equity - Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance, beginning of period				$ 6,390	$ 5,710
Comprehensive income
Net income	$ 0		$ 359	99	898
Foreign currency adjustments, net of income tax				76	(75)
Acquisition of noncontrolling interest		$ 5,275		(6,565)	0
Balance, end of period	$ 0		$ 6,533	$ 0	$ 6,533

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Option and RSA/RSU Activity (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	May 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock issuance authorized (in shares)		2,000,000
Options granted (in shares)	1,150,000
Restricted Stock Awards (RSAs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted in period (in shares)	352,036
Total grant date fair value of awards granted	$ 34.2
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant date fair value of awards granted	$ 37.8

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Option Summary (Details) $ / shares in Units, $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)$ / sharesshares
Options
Outstanding at beginning of period (in shares) | shares	4,641,600
Granted (in shares) | shares	1,150,000
Exercised (in shares) | shares	(464,564)
Expired or forfeited (in shares) | shares	(199,550)
Outstanding at end of period (in shares) | shares	5,127,486	4,641,600
Exercisable (in shares) | shares	1,975,811
Wtd. Average Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 62.29
Granted (in dollars per share) | $ / shares	98.42
Exercised (in dollars per share) | $ / shares	33.86
Expired or forfeited (in dollars per share) | $ / shares	82.92
Outstanding at end of period (in dollars per share) | $ / shares	72.17	$ 62.29
Exercisable (in dollars per share) | $ / shares	$ 42.71
Wtd. Average Remaining Contractual Life (in years)
Outstanding	7 years 8 months 12 days	7 years 9 months 18 days
Exercisable at end of period	6 years
Intrinsic Value (millions)
Outstanding | $	$ 144.8	$ 149.7
Exercisable at end of period | $	$ 112.5

Stock-Based Compensation - Rest

Stock-Based Compensation - Restricted Stock Awards and Units (Details) - RSAs and RSUs - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Awards
Outstanding at beginning of period (in shares)	344,250
Granted (in shares)	352,036
Forfeited (in shares)	(40,500)
Vested (in shares)	(22,750)
Outstanding at end of period (in shares)	633,036
Wtd. Average Grant-Date Fair Value
Outstanding at beginning of period (in dollars per share)	$ 81.39
Granted (in dollars per share)	97.06
Forfeited (in dollars per share)	80.72
Vested (in dollars per share)	61.57
Outstanding at end of period (in dollars per share)	$ 90.87
Intrinsic Value
Outstanding	$ 62.8	$ 31.7

Stock-Based Compensation - Empl

Stock-Based Compensation - Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Employee Stock Purchase Plan
Compensation expense	$ 11,244	$ 8,543	$ 30,407	$ 21,242
Employee Stock Purchase Plan
Employee Stock Purchase Plan
Offering period increments under the ESPP			6 months
Compensation expense			$ 3,000	$ 2,500
Shares issued			242,329
Shares reserved	2,757,671		2,757,671
Employee Stock Purchase Plan | Maximum
Employee Stock Purchase Plan
Payroll deduction, as a percentage of base wages, an employee may authorize to be applied toward the purchase of common stock under the ESPP			15.00%
Percentage of discount on the purchase price of common stock during the offering period under the ESPP			15.00%

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock-based compensation
Total stock-based compensation expense	$ 11,244	$ 8,543	$ 30,407	$ 21,242
Direct costs
Stock-based compensation
Total stock-based compensation expense	3,685	2,451	9,780	6,900
Selling, general and administrative
Stock-based compensation
Total stock-based compensation expense	7,559	5,319	20,627	13,569
Transaction-related costs
Stock-based compensation
Total stock-based compensation expense	$ 0	$ 773	$ 0	$ 773

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate	25.10%	40.00%
U.S. statutory rate	21.00%
Increase in liability for uncertain tax positions	$ 18.7

Commitments and Contingencies (

Commitments and Contingencies (Details) - Tax related claim on export of services provided $ in Millions	Sep. 30, 2019USD ($)
Commitments and Contingencies
Tax contingency, amount of claim	$ 4.9
Deposit made in tax litigation	$ 4.9

Derivatives - Hedging Instrumen

Derivatives - Hedging Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivatives in an asset position:
Notional amount	$ 625,000	$ 625,000
Asset/(Liability)	(3,805)	3,318
Interest rate swap | Designated as hedging instruments | Level 2 | Other assets
Derivatives in an asset position:
Notional amount	0	625,000
Asset/(Liability)	0	3,318
Interest rate swap | Designated as hedging instruments | Level 2 | Other long-term liabilities
Derivatives in an asset position:
Notional amount	625,000	0
Asset/(Liability)	$ (3,805)	$ 0

Derivatives - Cash Flow Hedging

Derivatives - Cash Flow Hedging Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Effect of derivatives on the consolidated statements of operations and comprehensive income (loss)
Interest expense, net	$ (12,974)	$ (14,423)	$ (37,834)	$ (43,860)
Cash flow hedging | Interest rate swap
Effect of derivatives on the consolidated statements of operations and comprehensive income (loss)
Amount of pre-tax (loss) gain recognized in other comprehensive income	(266)		(6,190)
Amount of pre-tax (loss) gain recognized in other comprehensive income		1,422		7,617
Amount of loss reclassified from accumulated other comprehensive loss into interest expense, net	$ (1,611)		$ (4,028)
Amount of loss reclassified from accumulated other comprehensive loss into interest expense, net		$ (1,463)		$ (4,980)

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)
Interest rate swap | Cash flow hedging
Derivative [Line Items]
Unrealized losses expected to be reclassified out of accumulated other comprehensive loss into interest expense over the next 12 months	$ 9.5

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Components (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Jan. 01, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,051,420
Other comprehensive loss before reclassifications	(31,335)
Reclassification adjustments	2,972
Balance at end of period	946,743
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(170,659)
Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income		$ 1,419
Balance at end of period	(197,603)
Foreign Currency Translation, Net of Tax
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(158,349)
Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income		0
Other comprehensive loss before reclassifications	(26,768)
Reclassification adjustments	0
Balance at end of period	(185,117)
Derivative Instruments, Net of Tax
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(12,310)
Impact from adoption of ASU 2018-02, Reclassification of certain tax effects from accumulated other comprehensive income		$ 1,419
Other comprehensive loss before reclassifications	(4,567)
Reclassification adjustments	2,972
Balance at end of period	$ (12,486)

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Increase (decrease) in other comprehensive loss before reclassifications	$ 31,335
Foreign currency translation | British Pound
Accumulated Other Comprehensive Income (Loss) [Line Items]
Change in valuation of U.S. Dollar during the period	(3.40%)
Increase (decrease) in other comprehensive loss before reclassifications	$ 7,400
Foreign currency translation | Euro
Accumulated Other Comprehensive Income (Loss) [Line Items]
Change in valuation of U.S. Dollar during the period	(4.60%)
Increase (decrease) in other comprehensive loss before reclassifications	$ 15,700
Foreign currency translation | Canadian Dollar
Accumulated Other Comprehensive Income (Loss) [Line Items]
Change in valuation of U.S. Dollar during the period	3.00%
Increase (decrease) in other comprehensive loss before reclassifications	$ (1,100)
Foreign currency translation | Russian Ruble
Accumulated Other Comprehensive Income (Loss) [Line Items]
Change in valuation of U.S. Dollar during the period	7.30%
Increase (decrease) in other comprehensive loss before reclassifications	$ (1,600)

Net Income Per Share (Details)

Net Income Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Reconciliation of basic to diluted weighted average shares outstanding
Basic weighted average common shares outstanding	64,771	64,261	65,096	63,891
Effect of dilutive stock options and other awards under share-based compensation programs (in shares)	1,442	2,245	1,511	2,367
Diluted weighted average common shares outstanding	66,213	66,506	66,607	66,258
Anti-dilutive shares	2,150	987	1,914	1,670

Segments (Details)

Segments (Details) $ in Thousands	Sep. 03, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)segment	Sep. 30, 2018USD ($)
Segment Reporting [Abstract]
Reportable segments | segment				2
Segment Reporting Information [Line Items]
Revenue		$ 780,691	$ 717,596	$ 2,266,022	$ 2,142,274
Selling, general and administrative expenses		95,542	92,553	291,439	275,424
Transaction-related costs		572	43,837	572	32,709
Depreciation and amortization expense		29,264	28,270	85,462	84,163
Loss (gain) on disposal of fixed assets, net		256	(15)	900	21
Income from operations		95,788	38,812	262,526	184,556
Interest expense, net		(12,974)	(14,423)	(37,834)	(43,860)
Loss on modification or extinguishment of debt	$ (1,900)	(1,855)	(454)	(1,855)	(454)
Foreign currency gains (losses), net		5,408	(1,809)	1,864	(1,416)
Other income (expense), net		15	(68)	(66)	(201)
Income before income taxes and equity in income of unconsolidated joint ventures		86,382	22,058	224,635	138,625
Direct costs (exclusive of depreciation and amortization)
Segment Reporting Information [Line Items]
Cost of revenues		389,304	371,422	1,153,441	1,134,509
Reimbursable expenses
Segment Reporting Information [Line Items]
Cost of revenues		169,965	142,717	471,682	430,892
Clinical Research
Segment Reporting Information [Line Items]
Revenue		719,005	656,979	2,087,863	1,966,762
Data Solutions
Segment Reporting Information [Line Items]
Revenue		61,686	60,617	178,159	175,512
Operating segments
Segment Reporting Information [Line Items]
Revenue		780,691	717,596	2,266,022	2,142,274
Segment profit		221,422	203,457	640,899	576,873
Operating segments | Direct costs (exclusive of depreciation and amortization)
Segment Reporting Information [Line Items]
Cost of revenues		389,304	371,422	1,153,441	1,134,509
Operating segments | Reimbursable expenses
Segment Reporting Information [Line Items]
Cost of revenues		169,965	142,717	471,682	430,892
Operating segments | Clinical Research
Segment Reporting Information [Line Items]
Revenue		719,005	656,979	2,087,863	1,966,762
Segment profit		206,345	184,225	593,852	524,955
Operating segments | Clinical Research | Direct costs (exclusive of depreciation and amortization)
Segment Reporting Information [Line Items]
Cost of revenues		342,695	330,037	1,022,329	1,010,915
Operating segments | Clinical Research | Reimbursable expenses
Segment Reporting Information [Line Items]
Cost of revenues		169,965	142,717	471,682	430,892
Operating segments | Data Solutions
Segment Reporting Information [Line Items]
Revenue		61,686	60,617	178,159	175,512
Segment profit		15,077	19,232	47,047	51,918
Operating segments | Data Solutions | Direct costs (exclusive of depreciation and amortization)
Segment Reporting Information [Line Items]
Cost of revenues		46,609	41,385	131,112	123,594
Operating segments | Data Solutions | Reimbursable expenses
Segment Reporting Information [Line Items]
Cost of revenues		0	0	0	0
Segment Reconciling Items
Segment Reporting Information [Line Items]
Selling, general and administrative expenses		95,542	92,553	291,439	275,424
Transaction-related costs		572	43,837	572	32,709
Depreciation and amortization expense		29,264	28,270	85,462	84,163
Loss (gain) on disposal of fixed assets, net		256	(15)	900	21
Income from operations		95,788	38,812	262,526	184,556
Interest expense, net		(12,974)	(14,423)	(37,834)	(43,860)
Loss on modification or extinguishment of debt		(1,855)	(454)	(1,855)	(454)
Foreign currency gains (losses), net		5,408	(1,809)	1,864	(1,416)
Other income (expense), net		$ 15	$ (68)	$ (66)	$ (201)

Segments - Segment Revenue by G

Segments - Segment Revenue by Geographic Location (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 780,691	$ 717,596	$ 2,266,022	$ 2,142,274
Total Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	541,037	505,063	1,583,771	1,495,536
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	528,782	493,667	1,546,503	1,460,190
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	12,255	11,396	37,268	35,346
Europe, Africa, and Asia-Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	239,654	212,533	682,251	646,738
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	191,994	170,252	551,460	516,442
Netherlands
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	30,144	28,334	82,839	87,340
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	17,516	13,947	47,952	42,956
Clinical Research
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	719,005	656,979	2,087,863	1,966,762
Clinical Research | Total Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	479,351	444,446	1,405,612	1,320,024
Clinical Research | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	467,096	433,050	1,368,344	1,284,678
Clinical Research | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	12,255	11,396	37,268	35,346
Clinical Research | Europe, Africa, and Asia-Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	239,654	212,533	682,251	646,738
Clinical Research | United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	191,994	170,252	551,460	516,442
Clinical Research | Netherlands
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	30,144	28,334	82,839	87,340
Clinical Research | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	17,516	13,947	47,952	42,956
Data Solutions
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	61,686	60,617	178,159	175,512
Data Solutions | Total Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	61,686	60,617	178,159	175,512
Data Solutions | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	61,686	60,617	178,159	175,512
Data Solutions | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	0	0	0	0
Data Solutions | Europe, Africa, and Asia-Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	0	0	0	0
Data Solutions | United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	0	0	0	0
Data Solutions | Netherlands
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	0	0	0	0
Data Solutions | Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 0	$ 0	$ 0	$ 0

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)	Oct. 28, 2019	Oct. 25, 2019	Sep. 30, 2019	Dec. 31, 2018
Long-term debt
Total debt			$ 1,391,533,000	$ 1,086,533,000
Credit Facilities
Long-term debt
Interest period, option one			1 month
Interest period, option two			2 months
Interest period, option three			3 months
Interest period, option four			6 months
Credit Facilities | Revolving Credit Facility
Long-term debt
Maximum borrowing capacity			$ 225,000,000
Interest period, option one			1 month
Interest period, option two			2 months
Interest period, option three			3 months
Interest period, option four			6 months
Credit Facilities | LIBOR | Minimum
Long-term debt
Applicable margin on variable rate basis			1.00%
Credit Facilities | LIBOR | Maximum
Long-term debt
Applicable margin on variable rate basis			2.00%
Credit Facilities | ABR | Minimum
Long-term debt
Applicable margin on variable rate basis			0.00%
Credit Facilities | ABR | Maximum
Long-term debt
Applicable margin on variable rate basis			1.00%
Term loans, first lien
Long-term debt
Total debt			$ 1,191,533,000	$ 916,533,000
Subsequent Event | Credit Facilities
Long-term debt
Interest period, option one	1 month
Interest period, option two	2 months
Interest period, option three	3 months
Interest period, option four	6 months
Subsequent Event | Credit Facilities | Term Debt
Long-term debt
Aggregate principal amount	$ 1,000,000,000
Periodic payment, percent of original balance	2.50%
Subsequent Event | Credit Facilities | Revolving Credit Facility
Long-term debt
Term		5 years
Maximum borrowing capacity	$ 750,000,000
Subsequent Event | Credit Facilities | LIBOR | Minimum
Long-term debt
Applicable margin on variable rate basis	1.00%
Subsequent Event | Credit Facilities | LIBOR | Maximum
Long-term debt
Applicable margin on variable rate basis	2.00%
Subsequent Event | Credit Facilities | ABR | Minimum
Long-term debt
Applicable margin on variable rate basis	0.00%
Subsequent Event | Credit Facilities | ABR | Maximum
Long-term debt
Applicable margin on variable rate basis	1.00%
Subsequent Event | Term loans, first lien
Long-term debt
Total debt	$ 1,191,500,000

Uncategorized Items - q3201910-

Label	Element	Value
Additional Paid-in Capital [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	$ 905,423,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	960,535,000
AOCI Attributable to Parent [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	(136,470,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	(169,240,000)
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	(158,349,000)
Common Stock [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	636,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	$ 654,000
Shares, Outstanding	us-gaap_SharesOutstanding	63,624,000
Shares, Outstanding	us-gaap_SharesOutstanding	65,395,000
Noncontrolling Interest [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	$ 5,710,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	6,390,000
Retained Earnings [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	100,595,000
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	253,081,000
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	(10,891,000)
Accounting Standards Update 2018-02 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(1,419,000)
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(60,587,000)
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (60,587,000)