Debt: Notes Payable (Details) - USD ($)	9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Aug. 31, 2017	May 31, 2015
Notes Payable
Proceeds from the Note Agreement		$ 12,500,000
Notes Payable | Prudential Investment Management, Inc
Notes Payable
Minimum prepayment	$ 1,000,000
Series A Notes | Prudential Investment Management, Inc
Notes Payable
Principal amount outstanding	$ 18,500,000
Note payable, face amount				$ 25,000,000
Term of notes payable	10 years
Interest rate (as a percent)	5.50%
Quarterly principal payment, first five years	$ 500,000
Quarterly principal payment, thereafter	750,000
Series B Notes | Prudential Investment Management, Inc
Notes Payable
Principal amount outstanding	$ 11,300,000
Note payable, face amount			$ 12,500,000
Term of notes payable	10 years
Interest rate (as a percent)	5.10%
Quarterly principal payment	$ 312,500