Share Based Compensation - Restricted Stock Units (Details) (2010 Stock Incentive Plan [Member], USD $)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013
Time-vested RSUs [Member]
Number of restricted stock units
Outstanding, beginning of period (in shares)	20,640
Granted (in shares)	25,540
Vested (in shares)	0
Forfeited (in shares)	(2,820)
Outstanding, end of period (in shares)	43,360
Weighted average grant date fair value
Granted (in usd per share)	$ 32.85
Vested (in usd per share)	$ 0.00
Forfeited (in usd per share)	$ 32.24
Outstanding, end of period (in usd per share)	$ 32.32	$ 31.66
Cumulative dividends, end of period	903
Performance-based RSUs [Member]
Number of restricted stock units
Outstanding, beginning of period (in shares)	66,233
Granted (in shares)	56,222
Vested (in shares)	0
Forfeited (in shares)	(562)
Performance-based adjustment (in shares)	14,042
Outstanding, end of period (in shares)	135,935.000
Weighted average grant date fair value
Granted (in usd per share)	$ 32.85
Vested (in usd per share)	$ 0.00
Forfeited (in usd per share)	$ 31.66
Performance-based adjustment (in usd per share)	$ 32.85
Outstanding, end of period (in usd per share)	$ 32.27	$ 31.66
Cumulative dividends, end of period	2,234