Shareholders' Equity (Schedule Of Shares Reserved For Future Issuance) (Details)	Sep. 29, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award
Class A shares and Class B shares reserved for issuance	12,719,189
Conversion Of Class B To Class A Shares
Share-based Compensation Arrangement by Share-based Payment Award
Class A shares and Class B shares reserved for issuance	7,495,224
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award
Class A shares and Class B shares reserved for issuance	1,946,413
2014 Long Term Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award
Class A shares and Class B shares reserved for issuance	1,979,454
2008 Stock Appreciation Rights Plan
Share-based Compensation Arrangement by Share-based Payment Award
Class A shares and Class B shares reserved for issuance	1,298,098