Shareholders' Equity (Narrative) (Details) (USD $)	12 Months Ended
Jan. 31, 2013
November 2011 Program
Equity, Class of Treasury Stock [Line Items]
Share repurchase authorized amount	$ 100,000,000
May 2012 Program
Equity, Class of Treasury Stock [Line Items]
Share repurchase authorized amount	$ 100,000,000.0

Amount of a stock repurchase plan authorized by an entity's Board of Directors.

No definition available.

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration