Common Stock and Share-Based Compensation (Tables)

12 Months Ended

Dec. 26, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options under Equity Plan and Non-Employee Director Plan

Information related to stock options under the Equity Plan and the Non-Employee Director Plan is summarized as follows:

	Shares			Weighted- Average Exercise Price		Weighted-Average Remaining Contractual Term in Years		Aggregate Intrinsic Value (in thousands)
Outstanding at December 28, 2019		315,678		$	186.53
Granted		26,402			393.54
Forfeited		(2,595	)		242
Exercised		(97,638	)		136.87
Outstanding at December 26, 2020		241,847		$	228.58		5.93	$	190,176
Exercisable at December 26, 2020		53,638		$	211.32		5.16	$	43,104
Vested and expected to vest at    December 26, 2020		217,604		$	227.97		5.91	$	171,246

Stock-Based Compensation Expense Included in Operating Expenses

The following table provides information regarding stock-based compensation expense included in operating expenses in the accompanying consolidated statements of comprehensive income:

	2020		2019		2018
	(in thousands)
Amounts included in advertising, promotional and    selling expenses	$	4,467	$	3,996	$	3,243
Amounts included in general and administrative    expenses		10,815		8,341		6,792
Total stock-based compensation expense	$	15,282	$	12,337	$	10,035
Amounts related to performance-based stock awards    included in total stock-based compensation expense	$	2,771	$	1,944	$	1,750

Weighted Average Assumptions used to Estimate Fair Value of Stock Options

Weighted average assumptions used to estimate fair values of stock options on the date of grants are as follows:

	2020			2019			2018
Expected volatility		32.6	%		32.1	%		34.0	%
Risk-free interest rate		1.09	%		2.63	%		2.68	%
Expected dividends		0	%		0	%		0	%
Exercise factor	2.1 times			2.33 times			2.52 times
Discount for post-vesting restrictions		0.0	%		0.0	%		0.0	%

Summary of Vesting Activities of Shares Issued Under Investment Share Program and Restricted Stock Awards

The following table summarizes vesting activities of shares issued under the investment share program and restricted stock awards:

	Number of Shares			Weighted Average Fair Value
Non-vested at December 28, 2019		122,142		$	213.52
Granted		42,530			350.96
Vested		(45,860	)		214.23
Forfeited		(4,496	)		236.63
Non-vested at December 26, 2020		114,316		$	263.47

Stock Repurchases

As of December 26, 2020, the Company has repurchased a cumulative total of approximately 13.8 million shares of its Class A Common Stock for an aggregate purchase price of approximately $840.7 million as follows:

	Number of Shares		Aggregate Purchase Price
	(in thousands)
Repurchased at December 30, 2017		13,447,346	$	752,352
2018 repurchases		349,691		88,312
Repurchased at December 29, 2018		13,797,037		840,664
2019 repurchases		—		—
Repurchased at December 28, 2019		13,797,037		840,664
2020 repurchases		—		—
Repurchased at December 26, 2020		13,797,037	$	840,664