Shareholders' Equity (Deficit): Dividends and Repurchase of Common Stock (Details) - USD ($)			12 Months Ended
	Aug. 16, 2017	Jul. 19, 2017	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Repurchase of Common Stock
Aggregate purchase price of shares repurchased (in dollars)			$ 1,846,400	$ 49,902,500	$ 1,573,900
Dividends
Cash dividends declared and paid (in dollars per share)			$ 0.56	$ 0.43	$ 0.37
Aggregate quarterly cash dividends declared and paid			$ 2,169,900	$ 1,765,000	$ 1,526,800
Tender Offer
Repurchase of Common Stock
Shares authorized for repurchase		400,000
Purchase of stock, price per share		$ 124.48
Number of shares repurchased	400,000
Aggregate purchase price of shares repurchased (in dollars)	$ 49,900,000
Common Stock Repurchase Program
Repurchase of Common Stock
Number of shares repurchased			12,384	17,194
Aggregate purchase price of shares repurchased (in dollars)			$ 1,800,000	$ 1,600,000
Aggregate purchase price per share of shares repurchased (in dollars per share)			$ 149.10	$ 91.54
Number of additional shares that can be repurchased			130,604