XML 71 R55.htm IDEA: XBRL DOCUMENT v3.3.1.900
Summary of Stock Option Activity (Parenthetical) (Detail)
12 Months Ended
Jan. 31, 2016
$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Vested percentage 100.00%
Market value on the last business day of the fiscal year $ 51.66