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Income Taxes - Narrative (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Valuation allowance for deferred tax assets | $ 45,495,000 | $ 32,768,000 | $ 27,700,000
Net change in the total valuation allowance | 12,800,000 | 5,100,000 |
Deferred tax liabilities, undistributed foreign earnings | 800,000 | 900,000 |
Unrecognized tax benefit, potentially expire in 2021 | 38,800,000 |  |
Total unrecognized tax benefits net of potential benefits | 202,100,000 | 19,100,000 | 20,200,000
Interest and penalties recognized as an expense | 1,900,000 | 600,000 | $ 0
Total accrued interest and penalties | 15,500,000 | 500,000 |
PRA Health Sciences, Inc |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Net change in the total valuation allowance | 9,300,000 |  |
Provision for income taxes |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Net change in the total valuation allowance | 4,400,000 | 3,600,000 |
Other Comprehensive Income |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Net change in the total valuation allowance | 900,000 | $ 1,500,000 |
Foreign Country |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Other non-U.S subsidiaries operating loss carryforwards for income tax | 42,300,000 |  |
Foreign Country | Tax Year 2022 to 2028 |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Additional operating loss carryforward | 19,900,000 |  |
Foreign Country | Tax Year 2029 to 2038 |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Additional operating loss carryforward | 19,900,000 |  |
Ireland | Foreign Country |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Ireland subsidiaries additional tax credit carryforward for income tax | 14,000,000 |  |
United States |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
U.S. Federal net operating loss carry forwards currently available for offset | 5,000,000 |  |
Alternative minimum tax credit carry forwards | 800,000 |  |
United States | Federal NOL's |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Net operating loss carryforwards | 10,349,000 |  |
U.S. federal net operating loss carry forwards | 10,300,000 |  |
Tax credit carry forward | 145,700,000 |  |
Other non-U.S subsidiaries operating loss carryforwards for income tax | 95,000 |  |
United States | Tax Year 2022 to 2035 | Federal NOL's |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
U.S. federal net operating loss carry forwards | 10,200,000 |  |
Additional operating loss carryforward | 10,238,000 |  |
United States | Tax Year 2036-2040 | Federal NOL's |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
U.S. federal net operating loss carry forwards | 100,000 |  |
Additional operating loss carryforward | 16,000 |  |
United States | State NOL's |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Net operating loss carryforwards | 296,981,000 |  |
Other non-U.S subsidiaries operating loss carryforwards for income tax | 44,370,000 |  |
United States | State NOL's | Tax Year 2022 to 2035 |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Additional operating loss carryforward | 227,538,000 |  |
United States | State NOL's | Tax Year 2036-2040 |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Additional operating loss carryforward | 25,073,000 |  |
Other | Foreign Country |  |  |
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items] |  |  |
Ireland subsidiaries additional tax credit carryforward for income tax | $ 5,300,000 |  |

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