Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Segment Reporting Information [Line Items]
Aggregate amortization expense	$ 1.5	$ 1.5	$ 1.7
Klein Associates Inc.
Segment Reporting Information [Line Items]
Goodwill, impairment	$ (1.5)