Investments - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 29, 2012 Y	Dec. 31, 2011 Y
Schedule of Available-for-sale Securities [Line Items]
Investments, maximum maturity period, years	5	5
Unrealized gains, net of unrealized losses, on the investments in the bond portfolio	$ 1,407,000	$ 786,000
Guarantee Payment Of Insurance Claims
Schedule of Available-for-sale Securities [Line Items]
Letters of credit outstanding	45,146,000
Current Investments
Schedule of Available-for-sale Securities [Line Items]
Investments providing collateral for letters of credit to guarantee insurance claims	35,528,000
Non-Current Investments
Schedule of Available-for-sale Securities [Line Items]
Investments providing collateral for letters of credit to guarantee insurance claims	14,634,000
Total non-current investments	$ 56,874,000