Marketable Securities at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 29, 2012	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	$ 1,496	$ 1,666
Mutual Funds | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	1,161	1,301
Mutual Funds | Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	289	314
Mutual Funds | Money market instruments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	46	51
Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	1,496	1,666
Level 1 | Mutual Funds | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	1,161	1,301
Level 1 | Mutual Funds | Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	289	314
Level 1 | Mutual Funds | Money market instruments
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Marketable securities	$ 46	$ 51