Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)		Sep. 27, 2019	Dec. 28, 2018
Assets
Money market securities		$ 209,968,000	$ 208,554,000
Trading securities held in deferred compensation plan		70,765,000	57,778,000
Total		170,680,000	145,486,000
Liabilities
Deferred compensation plan	[1]	71,182,000	59,349,000
Total		71,182,000	59,349,000
Money market securities
Assets
Money market securities	[2]	22,790,000	6,213,000
Fixed income securities
Assets
Fixed income available-for-sale securities	[3]	77,125,000	81,495,000
Trading securities held in deferred compensation plan	[4]	21,421,000	18,618,000
Equity securities
Assets
Trading securities held in deferred compensation plan	[4]	49,344,000	39,160,000
Fair Value, Inputs, Level 1
Assets
Total		93,555,000	63,991,000
Liabilities
Deferred compensation plan	[1]	71,182,000	59,349,000
Total		71,182,000	59,349,000
Fair Value, Inputs, Level 1 | Money market securities
Assets
Money market securities	[2]	22,790,000	6,213,000
Fair Value, Inputs, Level 1 | Fixed income securities
Assets
Fixed income available-for-sale securities	[3]	0	0
Trading securities held in deferred compensation plan	[4]	21,421,000	18,618,000
Fair Value, Inputs, Level 1 | Equity securities
Assets
Trading securities held in deferred compensation plan	[4]	49,344,000	39,160,000
Fair Value, Inputs, Level 2
Assets
Total		77,125,000	81,495,000
Liabilities
Deferred compensation plan	[1]	0	0
Total		0	0
Fair Value, Inputs, Level 2 | Money market securities
Assets
Money market securities	[2]	0	0
Fair Value, Inputs, Level 2 | Fixed income securities
Assets
Fixed income available-for-sale securities	[3]	77,125,000	81,495,000
Trading securities held in deferred compensation plan	[4]	0	0
Fair Value, Inputs, Level 2 | Equity securities
Assets
Trading securities held in deferred compensation plan	[4]	0	0
Fair Value, Inputs, Level 3
Assets
Total		0	0
Liabilities
Deferred compensation plan	[1]	0	0
Total		0	0
Fair Value, Inputs, Level 3 | Money market securities
Assets
Money market securities	[2]	0	0
Fair Value, Inputs, Level 3 | Fixed income securities
Assets
Fixed income available-for-sale securities	[3]	0	0
Trading securities held in deferred compensation plan	[4]	0	0
Fair Value, Inputs, Level 3 | Equity securities
Assets
Trading securities held in deferred compensation plan	[4]	$ 0	$ 0

[1] Included in accrued payroll and employee benefits and deferred compensation plan liabilities on the Company’s unaudited condensed consolidated balance sheet.

[2] Included in cash and cash equivalents on the Company’s unaudited condensed consolidated balance sheet.

[3] Included in short-term investments on the Company’s unaudited condensed consolidated balance sheet.

[4] Included in prepaid expenses and other current assets and deferred compensation plan assets on the Company’s unaudited condensed consolidated balance sheet.