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. 29, 2024	Jul. 01, 2023	Jun. 29, 2024	Jul. 01, 2023
Schedule Of Earnings Per Share Basic And Diluted By Common Class [Line Items]
Earnings to Common Shareholders, As reported - basic	$ 52,339	$ 58,035	$ 64,936	$ 49,079
Common shares, As reported - basic	11,898	12,268	11,976	12,288
EPS, As reported - basic	$ 4.4	$ 4.73	$ 5.42	$ 3.99
Add: effect of dilutive common shares Share-based awards	19	34	22	40
Earnings to Common Shareholders, Net effect of unvested participating shares				$ 0
Earnings to Common Shareholders, Net income per common share - diluted	$ 52,213	$ 57,913	$ 64,788	$ 48,981
Common Shares, Net income per common share - diluted	11,888	12,276	11,971	12,304
EPS, Net income per common share - diluted	$ 4.39	$ 4.72	$ 5.41	$ 3.98
Common Class A
Schedule Of Earnings Per Share Basic And Diluted By Common Class [Line Items]
Earnings to Common Shareholders, As reported - basic	$ 43,116	$ 48,130	$ 53,575	$ 40,722
Common shares, As reported - basic	9,801	10,174	9,881	10,196
EPS, As reported - basic	$ 4.4	$ 4.73	$ 5.42	$ 3.99
EPS, Net income per common share - diluted	$ 4.4		$ 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	$ 9,097	$ 9,783	$ 11,213	$ 8,259
Common shares, As reported - basic	2,068	2,068	2,068	2,068
EPS, As reported - basic	$ 4.4	$ 4.73	$ 5.42	$ 3.99
Earnings to Common Shareholders, Class B Common Stock	$ 9,097	$ 9,783	$ 11,213	$ 8,259
Class B Common Stock	2,068	2,068	2,068	2,068