Stockholders' Equity And Stock-Based Compensation (Narrative) (Details)								3 Months Ended		9 Months Ended		37 Months Ended	41 Months Ended
	Aug. 03, 2020 $ / shares	May 04, 2020 $ / shares	Jan. 29, 2020 $ / shares	Dec. 15, 2018 shares	Dec. 15, 2017 shares	Dec. 15, 2016 shares	Dec. 15, 2015 shares	Jun. 26, 2020 USD ($) vote $ / shares shares	Jun. 28, 2019 $ / shares	Jun. 26, 2020 USD ($) vote $ / shares shares	Jun. 28, 2019 $ / shares	Oct. 31, 2010	Mar. 28, 2014	Sep. 27, 2019 shares	Jul. 31, 2019 USD ($)	Jul. 25, 2018 USD ($)	Jan. 25, 2017 USD ($)	Oct. 31, 2014 USD ($)	Feb. 29, 2012 USD ($)	Jul. 31, 2011 USD ($)	Jul. 31, 2010 USD ($)	Nov. 30, 2009 USD ($)
Stockholders' Equity And Stock-Based Compensation [Line Items]
Options outstanding to purchase														7,201,000
Year end stock price | $ / shares										$ 65.76
Percentage of vesting per year												50.00%
Common stock, dividends declared (in dollars per share) | $ / shares		$ 0.22	$ 0.22					$ 0.22	$ 0.19	$ 0.66	$ 0.57
Remaining authorization to purchase additional shares | $								$ 232,000,000		$ 232,000,000
Authorization Amount | $								2,000,000,000		2,000,000,000												$ 250,000,000
Subsequent Event [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, dividends declared (in dollars per share) | $ / shares	$ 0.22
Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Stock options expected to vest | $								$ 26,700,000		$ 26,700,000
Employee stock options expected to be recognized over a weighted-average period										2 years 3 months 18 days
Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares exercisable (in shares)								994,455		994,455
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										7 years
Compensation requisite measurement period										3 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures										726,639
Performance-Based Stock Options [Member] | Executive Officer [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Of Target Award										125.00%
Performance-Based Stock Options [Member] | Executive Officer [Member] | Awarded Fiscal 2018 [Member] [Domain]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares exercisable (in shares)					330,000
Percentage Of Target Award					125.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures					264,000
Performance-Based Stock Options [Member] | Executive Officer [Member] | Awarded Fiscal 2016 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Of Target Award							125.00%
Options vested and exercisable							334,623
Performance-Based Stock Options [Member] | Executive Officer [Member] | Awarded Fiscal 2017 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares exercisable (in shares)						240,539
Percentage Of Target Award							95.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures						276,199
Performance-Based Stock Options [Member] | Executive Officer [Member] | Awarded Fiscal 2019 [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares exercisable (in shares)				301,375
Percentage Of Target Award				125.00%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures				241,100
Performance-Based Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Compensation requisite measurement period										3 years
Performance-Based Restricted Stock Units [Member] | Executive Officer [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares exercisable (in shares)								124,000		124,000
Percentage Of Target Award										200.00%
Options outstanding to purchase								62,000		62,000
Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										4 years
Stock options expected to vest | $								$ 133,600,000		$ 133,600,000
Employee stock options expected to be recognized over a weighted-average period										2 years 6 months
Restricted Stock Units (RSUs) [Member] | Employees and Officers [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										4 years
Restricted Stock Units (RSUs) [Member] | Awards Granted Prior to November 2010 [Member] | Directors [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period												3 years	1 year
Restricted Stock Units (RSUs) [Member] | Awards Granted After November 2010 [Member] | Directors [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award 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%
Additional Stock Approved [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Authorization Amount | $															$ 350,000,000.0	$ 350,000,000	$ 200,000,000	$ 200,000,000.0	$ 100,000,000	$ 250,000,000.0	$ 300,000,000.0
Class A Common Stock [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Common stock, shares authorized (shares)								500,000,000		500,000,000				500,000,000
Common stock, shares issued (shares)								64,338,677		64,338,677				63,911,270
Common stock, number of votes per share | vote								1		1
Common stock, shares outstanding (shares)								64,338,677		64,338,677				63,911,270
Class A Common Stock [Member] | 2005 Stock Plan. [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Shares authorized under plan								55,000,000.0		55,000,000.0
Options outstanding to purchase								6,896,000		6,896,000
Weighted average remaining contractual life										6 years 4 months 13 days
Options vested and exercisable								4,157,000		4,157,000
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				500,000,000
Common stock, shares issued (shares)								36,222,720		36,222,720				36,229,820
Common stock, number of votes per share | vote								10		10
Common stock, shares outstanding (shares)								36,222,720		36,222,720				36,229,820
Options Granted Prior To June 2008 [Member] | Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										4 years
Options expiration period										10 years
Options Granted From June Two Thousand Eight Member | Employee Stock Option [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										4 years
Options expiration period										10 years
Options Granted From June Two Thousand Eight Member | Employee Stock Option [Member] | One year anniversary date
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage of stock option becoming exercisable subjected to date of grant										25.00%
Options Granted From June Two Thousand Eight Member | Employee Stock Option [Member] | Over 36 equally installment periods following one year anniversary date
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										36 months
Awards Granted Prior To November Two Thousand Ten Member [Member] | Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										3 years
Awards Granted After November 2010 and Prior To Fiscal 2014 Member [Member] | Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										2 years
Awards Granted After November 2010 Member [Member] | Restricted Stock Units (RSUs) [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period										1 year
Minimum [Member] | Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Of Target Award										0.00%
Minimum [Member] | Performance-Based Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Of Target Award										0.00%
Maximum [Member] | Performance-Based Stock Options [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Of Target Award										125.00%
Maximum [Member] | Performance-Based Restricted Stock Units [Member]
Stockholders' Equity And Stock-Based Compensation [Line Items]
Percentage Of Target Award										200.00%