Net Income per Share - Computation of Earnings Per Share, Basic (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 26, 2021	Mar. 27, 2021	Jun. 27, 2020	Mar. 28, 2020	Jun. 26, 2021	Jun. 27, 2020
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income		$ 59,195	$ 65,565	$ 60,141	$ 18,234	$ 124,760	$ 78,375
Allocation of net income for basic:
Allocation of net income for basic common stock		$ 59,195		$ 60,141		$ 124,760	$ 78,375
Weighted average number of shares for basic:
Weighted-average number of common shares — basic		12,283		12,196		12,277	12,177
Net income per share for basic:
Net income per common share - basic		$ 4.82		$ 4.93		$ 10.16	$ 6.44
Common Class A
Allocation of net income for basic:
Allocation of net income for basic common stock		$ 48,710		$ 47,930		$ 102,354	$ 61,612
Weighted average number of shares for basic:
Weighted-average number of common shares — basic		10,108		9,720		10,072	9,572
Net income per share for basic:
Net income per common share - basic		$ 4.82		$ 4.93		$ 10.16	$ 6.44
Common Class B
Allocation of net income for basic:
Allocation of net income for basic common stock		$ 10,268		$ 11,836		$ 21,893	$ 16,237
Weighted average number of shares for basic:
Weighted-average number of common shares — basic	[1]	2,131		2,400		2,155	2,523
Net income per share for basic:
Net income per common share - basic		$ 4.82		$ 4.93		$ 10.16	$ 6.44
Unvested participating shares
Allocation of net income for basic:
Allocation of net income for basic unvested participating shares		$ 217		$ 375		$ 513	$ 526
Weighted average number of shares for basic:
Weighted-average number of common shares — basic		44		76		50	82

[1] Change in Class B Common Stock resulted from the conversion of 130,000 shares to Class A Common Stock on November 3, 2020 and 99,983 shares to Class A Common Stock on May 14, 2021 with the ending number of shares reflecting the weighted average for the period.