Acquisitions - Fair values of assets acquired and liabilities assumed (Details) - USD ($) $ in Thousands				9 Months Ended
	Mar. 01, 2022	Oct. 12, 2021	Nov. 02, 2020	May 31, 2022	Aug. 31, 2021
Business Acquisition [Line Items]
Goodwill				$ 978,860	$ 754,205
Revenues-generating contract
Business Acquisition [Line Items]
Acquisition date useful life				36 years
Acquired databases
Business Acquisition [Line Items]
Acquisition date useful life				15 years
Trade names
Business Acquisition [Line Items]
Acquisition date useful life				15 years
CUSIP Global Services
Business Acquisition [Line Items]
Current assets	$ 38,111
Goodwill	206,981
Current liabilities	(104,354)
Other liabilities	(1,482)
Total purchase price	1,932,256
Accounts receivable	38,000
Deferred revenues	98,800
CUSIP Global Services | Revenues-generating contract
Business Acquisition [Line Items]
Amortizable intangible assets	$ 1,583,000
Acquisition date useful life	36 years
CUSIP Global Services | Client relationships
Business Acquisition [Line Items]
Amortizable intangible assets	$ 164,000
Acquisition date useful life	26 years
CUSIP Global Services | Acquired databases
Business Acquisition [Line Items]
Amortizable intangible assets	$ 46,000
Acquisition date useful life	15 years
Cobalt Software, Inc.
Business Acquisition [Line Items]
Current assets		$ 540
Goodwill		43,554
Other assets		34
Current liabilities		(6,653)
Other liabilities		(7)
Total purchase price		50,018
Cobalt Software, Inc. | Client relationships
Business Acquisition [Line Items]
Amortizable intangible assets		$ 4,800
Acquisition date useful life		11 years
Cobalt Software, Inc. | Software technology
Business Acquisition [Line Items]
Amortizable intangible assets		$ 7,750
Acquisition date useful life		5 years
Truvalue Labs, Inc.
Business Acquisition [Line Items]
Current assets			$ 812
Goodwill			30,058
Other assets			5,299
Current liabilities			(3,069)
Other liabilities			(2,984)
Total purchase price			41,916
Truvalue Labs, Inc. | Client relationships
Business Acquisition [Line Items]
Amortizable intangible assets			$ 900
Acquisition date useful life			12 years
Truvalue Labs, Inc. | Software technology
Business Acquisition [Line Items]
Amortizable intangible assets			$ 8,100
Acquisition date useful life			7 years
Truvalue Labs, Inc. | Trade names
Business Acquisition [Line Items]
Amortizable intangible assets			$ 2,800
Acquisition date useful life			15 years