Receivables (Summary Of Net Receivables) (Details) - USD ($) $ in Thousands	Dec. 28, 2019	Dec. 29, 2018
Receivables [Abstract]
Client receivables	$ 1,245,670	$ 1,237,127
Less: Allowance for doubtful accounts	106,075	64,561
Client receivables, net of allowance	1,139,595	1,172,566
Other receivables		10,928
Total receivables, net	$ 1,139,595	$ 1,183,494