Recent Accounting Pronouncements: (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jul. 01, 2017	Jul. 01, 2017	Jun. 25, 2016
Recently Adopted Accounting Pronouncements
Excess tax benefits on exercised stock options, operating activities		$ 518,000	$ 9,700
Accounting Standards Update 2016-09
Recently Adopted Accounting Pronouncements
Excess tax benefits on exercised stock options, operating activities	$ 421,900	$ 518,000	9,700
Accounting Standards Update 2016-09 | Previously Reported
Recently Adopted Accounting Pronouncements
Excess tax benefits on exercised stock options, financing activities			$ 9,700