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Non-current bank credit lines and loan facilities - Narrative (Details) |  |  |  |  | 2 Months Ended | 4 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Dec. 29, 2021 USD ($) | Sep. 27, 2021 USD ($) | Jul. 01, 2021 USD ($) | Dec. 08, 2020 USD ($) tranche | Dec. 31, 2021 USD ($) | Nov. 09, 2021 | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Total financing costs |  |  |  |  |  |  | $ 182,423,000 | $ 13,019,000 | $ 13,276,000
Cash paid for interest |  |  |  |  |  |  | 106,205,000 | $ 13,062,000 | $ 13,059,000
Issue of senior notes, number of tranches | tranche |  |  |  | 2 |  |  |  |  |
Long-term debt at fair value |  |  |  |  | $ 5,507,200,000 |  | 5,507,200,000 |  |
PRA Health Sciences, Inc |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Total financing costs |  |  |  |  |  |  | $ 86,700,000 |  |
Term loan | London Interbank Offered Rate (LIBOR) |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  | 2.75% | 3.00% | 2.50% |  |
Basis spread on variable rate, step down percentage (in percent) |  |  |  |  |  |  | 0.25% |  |
First lien net leverage ratio |  |  |  |  | 4 |  | 4 |  |
Decrease in basis spread on variable rate |  |  |  |  | 0.25% |  |  |  |
Term loan | London Interbank Offered Rate (LIBOR) | Maximum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
First lien net leverage ratio |  |  |  |  | 4.00 |  | 4.00 |  |
Term loan | London Interbank Offered Rate (LIBOR) | Minimum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 0.50% |  |
First lien net leverage ratio |  |  |  |  | 1.00 |  | 1.00 |  |
Senior secured revolving loan facility | Variable rate component one | Base rate |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 0.60% |  |
Senior secured revolving loan facility | Variable rate component one | Base rate | Maximum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 1.00% |  |
Senior secured revolving loan facility | Variable rate component one | Base rate | Minimum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 0.25% |  |
Senior secured revolving loan facility | Variable rate component two | London Interbank Offered Rate (LIBOR) |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 1.60% |  |
Senior secured revolving loan facility | Variable rate component two | London Interbank Offered Rate (LIBOR) | Maximum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 2.00% |  |
Senior secured revolving loan facility | Variable rate component two | London Interbank Offered Rate (LIBOR) | Minimum |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Basis spread on variable rate (in percent) |  |  |  |  |  |  | 1.25% |  |
Senior Secured Credit Facility | Senior secured credit facility and senior secured notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt discount paid |  |  |  |  | $ 27,600,000 |  | $ 27,600,000 |  |
Senior Secured Credit Facility | Term loan |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  | $ 5,515,000,000 |  |  |  |  |  |
Debt instrument, interest rate (in percent) |  |  | 1.00% |  | 2.75% |  | 2.75% |  |
Repayments of senior debt | $ 500,000,000 | $ 13,800,000 |  |  |  |  |  |  |
Cash paid for interest | $ 40,800,000 | $ 40,400,000 |  |  |  |  |  |  |
Payments of Debt Restructuring Costs |  |  |  |  |  |  | $ 5,600,000 |  |
Line of credit | Senior secured revolving loan facility | Revolving loan facility |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Maximum borrowing capacity |  |  | $ 300,000,000 |  |  |  |  |  |
Long-term line of credit |  |  |  |  | $ 0 |  | 0 |  |
Letter of credit | Senior secured revolving loan facility | Revolving loan facility |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Letters of credit outstanding amount |  |  |  |  | $ 4,100,000 |  | $ 4,100,000 |  |
Senior Secured Notes | Senior Secured Notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  | $ 500,000,000 |  |  |  |  |  |
Debt instrument, interest rate (in percent) |  |  | 2.875% |  | 2.875% |  | 2.875% |  |
Senior Notes | Senior Notes 2020 |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Proceeds from issuance of long-term debt |  |  |  | $ 350,000,000 |  |  |  |  |
Effective interest rate (in percent) |  |  |  |  |  |  | 2.41% |  |
Repayments of debt |  |  | $ 364,000,000 |  |  |  |  |  |
Senior Notes | Series A notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  | $ 275,000,000 |  |  |  |  |
Debt instrument, interest rate (in percent) |  |  |  | 2.32% |  |  |  |  |
Senior Notes | Series B notes |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |
Debt instrument, face amount |  |  |  | $ 75,000,000 |  |  |  |  |
Debt instrument, interest rate (in percent) |  |  |  | 2.43% |  |  |  |  |

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- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
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