Shareholders' Equity (Deficit): Options Outstanding and Exercisable (Details) - Stock options - USD ($)	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Options Outstanding
Number Outstanding (in shares)	668,740
Weighted Average Remaining Contractual Life	6 years 4 months 28 days
Weighted Average Exercise Price (in dollars per share)	$ 53.73
Options Exercisable
Exercisable at the end of the period (in shares)	440,577
Weighted Average Exercise Price (in dollars per share)	$ 41.76
Additional disclosures
Total intrinsic value of options exercised	$ 400,000	$ 1,200,000	$ 8,700,000
Total fair value of shares vested	$ 6,200,000	$ 5,100,000	$ 3,900,000
Shares of previously owned common stock surrendered as payment for option shares exercised	587	0	1,207
Compensation expense	$ 1,694,800	$ 1,417,200	$ 1,153,600
Total unrecognized compensation expense	$ 4,000,000
Weighted average period for recognition of unrecognized compensation expense	2 years 6 months
$12.75 - $18.40
Stock options outstanding and exercisable
Range of Exercise Price, low end of range (in dollars per share)	$ 12.75
Range of Exercise Price, high end of range (in dollars per share)	$ 18.40
Options Outstanding
Number Outstanding (in shares)	52,261
Weighted Average Remaining Contractual Life	3 years 11 days
Weighted Average Exercise Price (in dollars per share)	$ 13.97
Options Exercisable
Exercisable at the end of the period (in shares)	52,261
Weighted Average Exercise Price (in dollars per share)	$ 13.97
$20.32 - $31.19
Stock options outstanding and exercisable
Range of Exercise Price, low end of range (in dollars per share)	20.32
Range of Exercise Price, high end of range (in dollars per share)	$ 31.19
Options Outstanding
Number Outstanding (in shares)	104,674
Weighted Average Remaining Contractual Life	3 years 4 months 6 days
Weighted Average Exercise Price (in dollars per share)	$ 25.20
Options Exercisable
Exercisable at the end of the period (in shares)	104,674
Weighted Average Exercise Price (in dollars per share)	$ 25.20
$32.92 - $51.17
Stock options outstanding and exercisable
Range of Exercise Price, low end of range (in dollars per share)	32.92
Range of Exercise Price, high end of range (in dollars per share)	$ 51.17
Options Outstanding
Number Outstanding (in shares)	128,519
Weighted Average Remaining Contractual Life	5 years 7 months 6 days
Weighted Average Exercise Price (in dollars per share)	$ 40.82
Options Exercisable
Exercisable at the end of the period (in shares)	117,203
Weighted Average Exercise Price (in dollars per share)	$ 39.82
$53.34 - $80.32
Stock options outstanding and exercisable
Range of Exercise Price, low end of range (in dollars per share)	53.34
Range of Exercise Price, high end of range (in dollars per share)	$ 80.32
Options Outstanding
Number Outstanding (in shares)	256,136
Weighted Average Remaining Contractual Life	7 years 5 months 16 days
Weighted Average Exercise Price (in dollars per share)	$ 62.87
Options Exercisable
Exercisable at the end of the period (in shares)	142,564
Weighted Average Exercise Price (in dollars per share)	$ 58.85
$82.72 - $91.93
Stock options outstanding and exercisable
Range of Exercise Price, low end of range (in dollars per share)	82.72
Range of Exercise Price, high end of range (in dollars per share)	$ 91.93
Options Outstanding
Number Outstanding (in shares)	127,150
Weighted Average Remaining Contractual Life	9 years 4 days
Weighted Average Exercise Price (in dollars per share)	$ 88.18
Options Exercisable
Exercisable at the end of the period (in shares)	23,875
Weighted Average Exercise Price (in dollars per share)	$ 82.72