CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 26, 2020	Dec. 28, 2019
Statement of Financial Position [Abstract]
Receivables, allowance for doubtful accounts	$ 15,952	$ 9,548
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized shares (in shares)	500,000	500,000
Preferred stock, issued shares (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, authorized shares (in shares)	75,000,000	75,000,000
Common stock, issued shares (in shares)	27,900,000	27,900,000
Common shares in treasury, shares	6,674,866	6,356,103