Basis Of Presentation (Details) (USD $) In Thousands, unless otherwise specified	Apr. 27, 2012	Jan. 27, 2012
Senior Notes Due 2022 At 4.20% [Member]
Unsecured senior notes		$ 400,000
Interest rate of debt instrument		4.20%
Senior Notes Due 2012 At 5.625% [Member]
Unsecured senior notes	$ 200,000	$ 200,000
Interest rate of debt instrument	5.625%	5.625%

Carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Senior note holders are paid off in full before any payments are made to junior note holders.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Name:	us-gaap_SeniorLongTermNotes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant