Shareholders' Equity (Deficit): Stock Options Activity (Details) - Stock options - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
Number of Shares
Outstanding at the beginning of the period (in shares)	597,700	526,712	613,727
Granted (in shares)	79,400	97,000	96,250
Exercised (in shares)	(8,360)	(21,012)	(176,700)
Forfeited (in shares)		(5,000)	(6,565)
Outstanding at the end of the period (in shares)	668,740	597,700	526,712	613,727
Exercisable at the end of the period (in shares)	440,577
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 48.50	$ 42.87	$ 31.46
Granted (in dollars per share)	91.46	73.31	71.39
Exercised (in dollars per share)	38.46	19.89	18.82
Forfeited (in dollars per share)		56.85	42.20
Outstanding at the end of the period (in dollars per share)	53.73	$ 48.50	$ 42.87	$ 31.46
Exercisable at the end of the period (in dollars per share)	$ 41.76
Weighted Average Remaining Contractual Life (years)
Outstanding	6 years 4 months 28 days	6 years 11 months 5 days	7 years 3 months 29 days	7 years 22 days
Exercisable at the end of the period	5 years 3 months 15 days
Intrinsic Value
Outstanding at the beginning of the period	$ 20,973,700	$ 26,446,700	$ 16,010,000
Outstanding at the end of the period	25,582,300	$ 20,973,700	$ 26,446,700	$ 16,010,000
Exercisable at the end of the period	$ 22,123,700
Weighted average assumptions and results used in estimation of fair value of options granted
Risk free interest rate (as a percent)	1.71%	1.75%	1.60%
Expected life (years)	6 years	6 years	6 years
Expected volatility (as a percent)	30.15%	33.20%	32.90%
Dividend yield (as a percent)	1.36%	1.66%	1.65%
Option fair value (in dollars per share)	$ 24.88	$ 21.02	$ 20.36