Shareholders' Equity (Deficit): Stock Option Plans and Stock-Based Compensation (Details) - Stock options - USD ($)	6 Months Ended		12 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Dec. 26, 2020
Number of Shares
Outstanding at the beginning of the period (in shares)	393,488
Granted (in shares)	34,000
Exercised (in shares)	(14,079)
Forfeited (in shares)	(2,700)
Outstanding at the end of the period (in shares)	410,709		393,488
Exercisable at the end of the period (in shares)	288,979
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 113.19
Granted (in dollars per share)	191.82
Exercised (in dollars per share)	85.96
Forfeited (in dollars per share)	151.06
Outstanding at the end of the period (in dollars per share)	120.39		$ 113.19
Exercisable at the end of the period (in dollars per share)	$ 98.91
Weighted Average Remaining Contractual Life (years)
Outstanding	5 years 6 months 10 days		5 years 7 months 9 days
Exercisable at the end of the period	4 years 2 months 1 day
Intrinsic Value
Outstanding	$ 29,093,400		$ 27,864,900
Exercisable at the end of the period	$ 26,593,700
Weighted average assumptions and results used in estimation of fair value of options granted
Risk free interest rate (as a percent)	0.90%	0.40%
Expected life (years)	6 years	6 years
Expected volatility (as a percent)	25.07%	25.03%
Dividend yield (as a percent)	2.74%	1.92%
Option fair value (in dollars per share)	$ 32.70	$ 26.55
Additional disclosures
Compensation expense	$ 698,100	$ 538,000
Total unrecognized compensation expense	$ 3,200,000
Weighted average period for recognition of unrecognized compensation expense	2 years 9 months 18 days