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Goodwill and Intangible Assets - Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Jan. 31, 2016
Jan. 31, 2015
Jan. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]      
Amortization of intangible assets $ 5.6 $ 3.6 $ 2.0