Description of Business and Summary of Significant Accounting Policies - Condensed Consolidated Statements of Changes in Shareholders' Equity (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended 12 Months Ended
Oct. 02, 2020
Jul. 03, 2020
Apr. 03, 2020
Sep. 27, 2019
Jun. 28, 2019
Mar. 29, 2019
Oct. 02, 2020
Sep. 27, 2019
Dec. 31, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Balance $ 269,435 $ 264,243 $ 258,865 $ 238,683 $ 227,251 $ 220,324 $ 258,865 $ 220,324 $ 220,324
Net income 10,391 1,111 8,668 7,841 7,617 7,074 20,170 22,532  
Balance 283,805 269,435 264,243 245,801 238,683 227,251 283,805 245,801 258,865
As Previously Reported                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Balance     261,381 239,676 228,244 221,300 261,381 221,300 221,300
Net income       9,382 7,617 7,091   24,090  
Balance       248,335 239,676 228,244   248,335 261,381
Correction                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Balance     (2,516) (993) (993) (976) (2,516) (976) (976)
Net income       (1,541) 0 (17)   (1,558) (1,500)
Balance       (2,534) (993) (993)   (2,534) (2,516)
Retained Earnings                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Balance 194,854 193,743 185,075 166,590 158,973 151,640 185,075 151,640 151,640
Net income 10,391 1,111 8,668 7,841 7,617 7,074      
Balance $ 205,245 $ 194,854 $ 193,743 174,431 166,590 158,973 $ 205,245 174,431 185,075
Retained Earnings | As Previously Reported                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Balance       167,583 159,966 152,616   152,616 152,616
Net income       9,382 7,617 7,091      
Balance       176,965 167,583 159,966   176,965  
Retained Earnings | Correction                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Balance       (993) (993) (976)   (976) $ (976)
Net income       (1,541) 0 (17)      
Balance       $ (2,534) $ (993) $ (993)   $ (2,534)