Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Tax [Line Items]
US Tax Act Impact - Transition Tax				$ 24,000
Other Tax Expense (Benefit)		$ (5,500)	$ (600)	$ (6,100)
Effective Income Tax Rate Reconciliation, Percent	22.10%	2.00%	22.10%	7.00%
Provision for income taxes	$ 25,737	$ 2,306	$ 64,012	$ 16,809
TS
Tax [Line Items]
Deferred Other Tax Expense (Benefit)				$ (13,000)