Computation of Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2016	[1]	Sep. 24, 2016	Jun. 25, 2016	Mar. 26, 2016	Dec. 26, 2015	Sep. 26, 2015	Jun. 27, 2015	Mar. 28, 2015	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Allocation of net income for basic common stock										$ 87,349	$ 98,414	$ 90,743
Weighted-average number of common shares-diluted										12,796	13,520	13,484
Net income per common share-basic	$ 1.77		$ 2.53	$ 2.11	$ 0.55	$ 1.25	$ 2.93	$ 2.24	$ 1.04	$ 6.93	$ 7.46	$ 6.96
Net income per common share-diluted	$ 1.75		$ 2.48	$ 2.06	$ 0.53	$ 1.21	$ 2.85	$ 2.18	$ 1.00	$ 6.79	$ 7.25	$ 6.69
Common Class A
Schedule of Earnings Per Share, Basic and Diluted, by Common Class [Line Items]
Allocation of net income for basic common stock										$ 63,717	$ 71,798	$ 64,027
Allocation of net income to Class B Common Stock										23,190	26,154	26,207
Net effect of unvested participating shares										9	14	19
Net Income for diluted common stock										$ 86,916	$ 97,966	$ 90,253
Weighted-average number of common shares-basic										9,189	9,619	9,202
Add: effect of dilutive potential common share-based awards										263	397	516
Weighted average number of shares of Class B Common Stock										3,344	3,504	3,766
Weighted-average number of common shares-diluted										12,796	13,520	13,484
Net income per common share-basic										$ 6.93	$ 7.46	$ 6.96
Net income per common share-diluted										$ 6.79	$ 7.25	$ 6.69

[1] During the fourth quarter of 2016, the Company recorded a $3.6 million decrease in stock-based compensation expense related to the planned retirement of the Company's Chief Executive Officer in 2018.