Income Taxes - Additional Information (Detail) $ in Millions	6 Months Ended
	Jul. 31, 2019 USD ($)
Income Taxes [Line Items]
Unrecognized tax benefits	$ 38.7
U.S. federal tax authorities [Member] | Earliest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year	2013
U.S. federal tax authorities [Member] | Latest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year	2018
U.S. state tax authorities [Member] | Earliest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year	2009
U.S. state tax authorities [Member] | Latest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year	2018
Foreign tax authorities [Member] | Earliest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year	2013
Foreign tax authorities [Member] | Latest tax year [Member]
Income Taxes [Line Items]
Income tax examination, year	2018