Share Based Compensation - Outstanding stock units (Details) - Director [Member]	12 Months Ended
	Jan. 31, 2017 $ / shares shares
Number of stock units
Outstanding, beginning of period (in shares) | shares	93,734
Granted (in shares) | shares	18,750
Deferred retainers (in shares) | shares	3,125
Dividends (in shares) | shares	2,681
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | shares	19,641
Outstanding, end of period (in shares) | shares	98,649
Weighted average price
Outstanding, beginning of period (in usd per share) | $ / shares	$ 20.82
Granted (in usd per share) | $ / shares	19.20
Deferred retainers (in usd per share) | $ / shares	19.20
Dividends (in usd per share) | $ / shares	19.68
Vested (in usd per share) | $ / shares	18.88
Outstanding, end of period (in usd per share) | $ / shares	$ 20.82