Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Jun. 28, 2013		Dec. 28, 2012
Assets
Money market securities	$ 63,843	[1]	$ 49,134	[2]
Total	103,565		97,104
Liabilities
Deferred compensation plan	33,175	[3]	26,984	[4]
Total	33,175		26,984
Fixed income securities
Assets
Fixed income available for sale securities	6,417	[5]	20,881	[6]
Fixed income trading securities held in deferred compensation plan	10,668	[7]	9,911	[8]
Equity securities
Assets
Equity trading securities held in deferred compensation plan	22,637	[7]	17,178	[8]
Fair Value, Inputs, Level 1
Assets
Money market securities	63,843	[1]	49,134	[2]
Total	97,148		76,223
Liabilities
Deferred compensation plan	33,175	[3]	26,984	[4]
Total	33,175		26,984
Fair Value, Inputs, Level 1 | Fixed income securities
Assets
Fixed income available for sale securities	0	[5]	0	[6]
Fixed income trading securities held in deferred compensation plan	10,668	[7]	9,911	[8]
Fair Value, Inputs, Level 1 | Equity securities
Assets
Equity trading securities held in deferred compensation plan	22,637	[7]	17,178	[8]
Fair Value, Inputs, Level 2
Assets
Money market securities	0	[1]	0	[2]
Total	6,417		20,881
Liabilities
Deferred compensation plan	0	[3]	0	[4]
Total	0		0
Fair Value, Inputs, Level 2 | Fixed income securities
Assets
Fixed income available for sale securities	6,417	[5]	20,881	[6]
Fixed income trading securities held in deferred compensation plan	0	[7]	0	[8]
Fair Value, Inputs, Level 2 | Equity securities
Assets
Equity trading securities held in deferred compensation plan	0	[7]	0	[8]
Fair Value, Inputs, Level 3
Assets
Money market securities	0	[1]	0	[2]
Total	0		0
Liabilities
Deferred compensation plan	0	[3]	0	[4]
Total	0		0
Fair Value, Inputs, Level 3 | Fixed income securities
Assets
Fixed income available for sale securities	0	[5]	0	[6]
Fixed income trading securities held in deferred compensation plan	0	[7]	0	[8]
Fair Value, Inputs, Level 3 | Equity securities
Assets
Equity trading securities held in deferred compensation plan	$ 0	[7]	$ 0	[8]

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

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

[3] Included in accrued liabilities and deferred compensation on the Company’s unaudited condensed consolidated balance sheet.

[4] Included in accrued liabilities and deferred compensation on the Company’s consolidated balance sheet.

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

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

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

[8] Included in other current assets and deferred compensation plan assets on the Company’s consolidated balance sheet.