Stockholders' Equity And Stock-Based Compensation (Narrative) (Details) - USD ($)	3 Months Ended		37 Months Ended	41 Months Ended
	Jan. 01, 2016	Dec. 26, 2014	Oct. 31, 2010	Mar. 28, 2014	Sep. 25, 2015
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options outstanding to purchase					8,835,000
Year end stock price	$ 33.65
Percentage of vesting per year			50.00%
Common stock, dividends declared (in dollars per share)	$ 0.12	$ 0.10
Remaining authorization to purchase additional shares	$ 113,300,000
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest	$ 90,700,000
Employee stock options expected to be recognized over a weighted-average period	2 years 10 months 24 days
Executive Officer [Member] | Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	419,623
Employees and Officers [Member] | Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period	4 years
Awards Granted Prior to November 2010 [Member] | Directors [Member] | Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period			3 years	1 year
Awards Granted After November 2010 [Member] | Directors [Member] | Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period			2 years
Awards Granted Under 2005 Stock Plan Prior To February 2011 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Terms for issuance of stock	2
Awards Granted Under 2005 Stock Plan From February 2011 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Terms for issuance of stock	1.6
Employee Stock Purchase Plan [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage of compensation withheld by employees to purchase common stock	10.00%
Common stock purchase price determined over percentage of closing price	15.00%
Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest	$ 45,500,000
Employee stock options expected to be recognized over a weighted-average period	2 years 8 months 12 days
Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)	500,000,000				500,000,000
Common stock, shares issued (shares)	52,089,249				50,291,426
Common stock, shares outstanding (shares)	52,089,249				50,291,426
Class A Common Stock [Member] | 2005 Stock Plan. [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares authorized under plan	29,000,000
Options outstanding to purchase	10,684,000
Weighted average remaining contractual life	7 years 6 months
Options vested and exercisable	5,188,000
Class A Common Stock [Member] | Employee Stock Purchase Plan [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Maximum value of common stock available for eligible employees	$ 25,000
Maximum number of common stock available for eligible employees	1,000
Purchase period	6 months
Look back commencement period	1 year
Class B Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)	500,000,000				500,000,000
Common stock, shares issued (shares)	48,681,489				50,743,311
Common stock, shares outstanding (shares)	48,681,489				50,743,311
Options Granted Prior To June 2008 [Member] | Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options expiration period	10 years
Options Granted From June 2008 [Member] | Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options vesting period	4 years
Percentage of stock option becoming exercisable subjected to date of grant	25.00%