Stock-Based Compensation (Narrative) (Details)	6 Months Ended
	Jul. 31, 2011 years
Minimum [Member] | Stock Option Awards [Member]
Requisite vesting period, years	3
Minimum [Member] | Restricted Stock [Member]
Requisite vesting period, years	3
Maximum [Member] | Stock Option Awards [Member]
Requisite vesting period, years	4
Maximum [Member] | Restricted Stock [Member]
Requisite vesting period, years	4
Performance Unit Awards [Member]
The Maximum Number of Shares Issued for Performance Unit Awards	527,700
The Maximum Number of Shares Earned for Performance Unit Awards	960,400
The Maximum Number of Shares Settled in Cash for Performance Unit Awards	432,700
Target performance metrics for performance unit awards, next fiscal year	100.00%
Target performance metrics for performance unit awards, current fiscal year	200.00%
Target performance metrics for performance unit awards, previous fiscal year	200.00%
Employee Stock Unit Awards [Member]
Requisite vesting period, years	4
Non-Employee Director Stock Unit Awards [Member]
Requisite vesting period, years	1