v3.20.1

Business combination - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Aug. 30, 2019	Jan. 31, 2020	Jan. 31, 2019
Business Acquisition [Line Items]
Acquisition costs		$ 40,810	$ 2,121
WageWorks, Inc.
Business Combinations [Abstract]
Merger related costs, price per share	$ 51.35
Business Acquisition [Line Items]
Merger related costs, price per share	$ 51.35
Aggregate fair value of WageWorks stock acquired	$ 2,000,000	2,122,100
Cash paid	816,900
Borrowing pursuant to term loan facility	1,220,000
Goodwill		1,330,000
Acquisition costs		40,800
Contribution of revenue		$ 184,700
WageWorks, Inc. | Term Loan Facility | Line of Credit
Business Acquisition [Line Items]
Cash paid	$ 30,500

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