XML 43 R32.htm IDEA: XBRL DOCUMENT v3.7.0.1
Fair Value - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jul. 31, 2017
Jul. 31, 2016
Jul. 31, 2017
Jul. 31, 2016
Fair Value Disclosures [Abstract]        
Impairment charges $ 0 $ 0 $ 0 $ 0