Summary of Significant Accounting Policies (Accrued Warranty Liability Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 25, 2020
Accrued warranty and service liabilities
Balance, beginning of year	$ 13,082	$ 12,785
Assumed in business acquisition	23	155
Charged to expense	10,764	8,270
Margin on parts sales reversed	3,475	2,960
Reductions for claims settled	(12,881)	(11,088)
Balance, end of year	$ 14,463	$ 13,082