Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended			9 Months Ended
	Dec. 22, 2017	Oct. 03, 2020	Jul. 04, 2020	Sep. 28, 2019	Oct. 03, 2020	Sep. 28, 2019
Income Taxes [Line Items]
Income tax expense		$ 5,680,000		$ 3,873,000	$ 9,351,000	$ 11,271,000
Effective tax rates	25.00%	24.70%		20.40%	21.00%	21.80%
Income tax expense, discrete item		$ 0		$ 665,000	$ 737,000	$ 1,700,000
Refunds of state income taxes					553,000
Refunds of tax cuts and Jobs Act, income taxes					$ 700,000
Effective tax rates, excluding discrete item		24.70%		24.80%	24.60%	25.30%
Payment of estimated federal and state income taxes		$ 4,000,000.0	$ 0	$ 4,300,000		$ 10,800,000
Federal And State Research And Development Tax Credit [Member]
Income Taxes [Line Items]
Tax credit true-ups to actual from assumptions		$ 319,000		$ 146,000		$ 146,000