Shareholders' Equity (Deficit): Stock Option Plans and Stock-Based Compensation (Details) - Stock options - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Dec. 30, 2017	Feb. 20, 2011
Number of Shares
Outstanding at the beginning of the period (in shares)	658,184
Granted (in shares)	0
Exercised (in shares)	(8,677)
Outstanding at the end of the period (in shares)	649,507		658,184
Exercisable at the end of the period (in shares)	468,728
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 72.33
Exercised (in dollars per share)	40.14
Outstanding at the end of the period (in dollars per share)	72.76		$ 72.33
Exercisable at the end of the period (in dollars per share)	$ 58.83
Weighted Average Remaining Contractual Life (years)
Outstanding	5 years 7 months 24 days		5 years 10 months 13 days
Exercisable at the end of the period	4 years 7 months 13 days
Intrinsic Value
Outstanding	$ 37,811,700		$ 37,723,800
Exercisable at the end of the period	$ 33,734,700
Weighted average assumptions and results used in estimation of fair value of options granted
Risk free interest rate (as a percent)		2.05%
Expected life (years)		6 years
Expected volatility (as a percent)		27.12%
Dividend yield (as a percent)		1.16%
Option fair value (in dollars per share)		$ 30.78
Additional disclosures
Shares of previously owned common stock surrendered as payment for option shares exercised	2,249
Compensation expense	$ 490,800	$ 477,000
Total unrecognized compensation expense	$ 3,800,000
Weighted average period for recognition of unrecognized compensation expense	2 years 3 months 18 days
2001 Plan
Stock Option Plans
Number of shares authorized for issuance				750,000
2010 Plan
Stock Option Plans
Number of shares authorized for issuance	700,000
Nonemployee Directors Plan
Stock Option Plans
Number of shares authorized for issuance	350,000