Shareholders' Equity (Narrative) (Details) - shares	Jul. 31, 2017	May 29, 2015
Stockholders' Equity Note [Abstract]
Number of shares authorized to be repurchased (in shares)		14,000,000.0
Remaining number of shares authorized to be repurchased (in shares)	7,173,842

The remaining number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant