Net Income per Share - Computation of Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 28, 2025	Jun. 29, 2024	Jun. 28, 2025	Jun. 29, 2024
Schedule Of Earnings Per Share Basic And Diluted By Common Class [Line Items]
Earnings to Common Shareholders, As reported - basic	$ 60,433	$ 52,339	$ 84,845	$ 64,936
Common shares, As reported - basic	11,090	11,898	11,183	11,976
EPS, As reported - basic	$ 5.45	$ 4.4	$ 7.59	$ 5.42
Add: effect of dilutive common shares Share-based awards	9	19	9	22
Earnings to Common Shareholders, Net income per common share - diluted	$ 60,262	$ 52,213	$ 84,616	$ 64,788
Common Shares, Net income per common share - diluted	11,067	11,888	11,163	11,971
EPS, Net income per common share - diluted	$ 5.45	$ 4.39	$ 7.58	$ 5.41
Common Class A
Schedule Of Earnings Per Share Basic And Diluted By Common Class [Line Items]
Earnings to Common Shareholders, As reported - basic	$ 48,993	$ 43,116	$ 68,927	$ 53,575
Common shares, As reported - basic	8,990	9,801	9,086	9,881
EPS, As reported - basic	$ 5.45	$ 4.4	$ 7.59	$ 5.42
EPS, Net income per common share - diluted	$ 5.45	$ 4.4	$ 7.59	$ 5.42
Common Class B
Schedule Of Earnings Per Share Basic And Diluted By Common Class [Line Items]
Earnings to Common Shareholders, As reported - basic	$ 11,269	$ 9,097	$ 15,689	$ 11,213
Common shares, As reported - basic	2,068	2,068	2,068	2,068
EPS, As reported - basic	$ 5.45	$ 4.4	$ 7.59	$ 5.42
Earnings to Common Shareholders, Class B Common Stock	$ 11,269	$ 9,097	$ 15,689	$ 11,213
Class B Common Stock	2,068	2,068	2,068	2,068