Acquisitions - Narrative (Details) £ / shares in Units, $ in Thousands, £ in Millions				3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2024 USD ($)	Jan. 23, 2023 USD ($) employee	Jan. 23, 2023 GBP (£) employee	Mar. 31, 2024 USD ($)	Apr. 02, 2023 USD ($)	Mar. 31, 2024 USD ($)	Apr. 02, 2023 USD ($)	Oct. 01, 2023 USD ($) employee program	Oct. 02, 2022 USD ($)	Sep. 23, 2022 £ / shares
Business Acquisition [Line Items]
Goodwill				$ 1,977,688		$ 1,977,688		$ 1,880,244
Pence per share expected to be acquired | £ / shares										£ 2.22
Acquisition and integration expenses				$ 0	$ 19,944	0	$ 23,705
Reduction in contingent earn-out liabilities						$ 0	8,500
Minimum
Business Acquisition [Line Items]
Significant unobservable input, earn-out period						3 years
Minimum | Existing customer contracts
Business Acquisition [Line Items]
Useful life of intangible assets				1 year		1 year
Maximum
Business Acquisition [Line Items]
Significant unobservable input, earn-out period						5 years
Maximum | Existing customer contracts
Business Acquisition [Line Items]
Useful life of intangible assets				12 years		12 years
LS Technologies
Business Acquisition [Line Items]
Total purchase price	$ 102,000
Initial cash payments	76,000
Cash holdback related to tax reserve	4,000
Equity interests issued and issuable	22,000
Intangible assets	21,000
Net tangible assets	10,000
Goodwill	71,000
LS Technologies | Maximum
Business Acquisition [Line Items]
Equity interests issued and issuable	$ 45,000
RPS Group PLC
Business Acquisition [Line Items]
Total purchase price		$ 784,000	£ 633
Intangible assets		174,094
Goodwill		$ 652,762
Number of employees | employee		5,000	5,000
Acquisition and integration expenses					$ 19,900		$ 23,700
Net purchase price		$ 675,000
RPS Group PLC | Foreign Exchange Forward
Business Acquisition [Line Items]
Foreign currency forward contract, asset fair value		$ 109,300							$ 19,900
Amyx, Inc.
Business Acquisition [Line Items]
Total purchase price								$ 120,900
Number of employees | employee								500
Number of government programs acquired | program								30
Payables related to promissory note								$ 100,000
Receivables (payables) related to estimated post-closing adjustments								8,700
Contingent earn-out liability								12,200
Aggregate maximum of contingent consideration								$ 25,000