Shareholders' Equity (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Jan. 31, 2012
Shareholders' Equity [Abstract]
Share repurchase authorized amount	$ 400.0

The amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

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