CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 25, 2021	Dec. 26, 2020
Common Class A
Common stock, par value (in dollars per share)	$ 3	$ 3
Common stock, shares authorized (in shares)	80,000,000	80,000,000
Common stock, shares issued (in shares)	14,792,647	14,557,435
Common stock, shares outstanding (in shares)	14,792,647	14,557,435
Common Class B
Common stock, par value (in dollars per share)	$ 3	$ 3
Common stock, shares authorized (in shares)	16,000,000	16,000,000
Common stock, shares issued (in shares)	1,004,975	880,313
Common stock, shares outstanding (in shares)	1,004,975	880,313