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Goodwill and Intangible Assets - Schedule of changes in goodwill by reporting unit (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020
Goodwill [Roll Forward] |  |
Opening balance | $ 1,695,688 | $ 1,574,466
Goodwill relating to acquisitions consummated during the period | 44,216 | 123,595
Impact of measurement period adjustments | 1,205 | (5,653)
Effect of exchange rate fluctuations | (10,082) | 3,280
Closing balance | 1,731,027 | 1,695,688
BCMI |  |
Goodwill [Roll Forward] |  |
Opening balance | 420,172 | 417,213
Goodwill relating to acquisitions consummated during the period | 4,167 | 2,559
Impact of measurement period adjustments | 35 | (542)
Effect of exchange rate fluctuations | (3,117) | 942
Closing balance | 421,257 | 420,172
CGRLH |  |
Goodwill [Roll Forward] |  |
Opening balance | 607,574 | 555,130
Goodwill relating to acquisitions consummated during the period | 7,032 | 52,612
Impact of measurement period adjustments | 309 | (1,372)
Effect of exchange rate fluctuations | (3,795) | 1,204
Closing balance | 611,120 | 607,574
HMS |  |
Goodwill [Roll Forward] |  |
Opening balance | 667,942 | 602,123
Goodwill relating to acquisitions consummated during the period | 33,017 | 68,424
Impact of measurement period adjustments | 861 | (3,739)
Effect of exchange rate fluctuations | (3,170) | 1,134
Closing balance | $ 698,650 | $ 667,942

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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)(1)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=120320667&loc=SL49117168-202975 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 10 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=84165509&loc=d3e56426-112766 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
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