Condensed Consolidated Statement Of Stockholders' Equity (Parenthetical)	6 Months Ended
Jun. 26, 2011
Treasury stock, purchased	142,817
Common Class A [Member]
Class A shares issued	296,774

Number of shares issued during the period as a result of an employee stock purchase plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 5

Name:	us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration