Contract Balances (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Revenue from Contract with Customer [Abstract]
Contract assets	$ 13.4	$ 11.9
Contract assets, noncurrent	0.9	1.3
Revenue recognized that was included in contract liability balance at the beginning of the period	$ 374.8	$ 264.0	$ 180.4
Payment term	30 days