Shareholders' Equity: (Details 2) (Stock options, USD $)	3 Months Ended		12 Months Ended
	Mar. 29, 2014	Mar. 30, 2013	Dec. 28, 2013
Number of Shares
Outstanding at the beginning of the period (in shares)	526,712
Exercised (in shares)	(15,125)
Outstanding at the end of the period (in shares)	511,587		526,712
Exercisable at the end of the period (in shares)	258,762
Granted (in shares)	0	0
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 42.87
Exercised (in dollars per share)	$ 15.05
Outstanding at the end of the period (in dollars per share)	$ 43.69		$ 42.87
Exercisable at the end of the period (in dollars per share)	$ 30.50
Weighted Average Remaining Contractual Life (years)
Outstanding	7 years 1 month 20 days		7 years 3 months 29 days
Exercisable at the end of the period	5 years 11 months 1 day
Intrinsic Value
Outstanding at the beginning of the period	$ 26,446,700
Outstanding at the end of the period	16,222,100		26,446,700
Exercisable at the end of the period	$ 11,418,400
2001 Plan
Stock option plans
Number of shares authorized for issuance	750,000
2010 Plan
Stock option plans
Number of shares authorized for issuance	250,000
Nonemployee Directors Plan
Stock option plans
Number of shares authorized for issuance	300,000