Financial Instruments (Details) (Recurring [Member], USD $) In Thousands, unless otherwise specified	Jul. 01, 2012	Jan. 01, 2012
Carrying value and estimated fair value of financial instruments
Interest rate swap derivative assets	$ 7,256	$ 7,440
Restricted investments:
Guaranteed Investment Contract	5,742	5,742
Guaranteed Repurchase Agreements	41,590	33,821
Rabbi Trust	8,941	8,016
Fixed income securities	2,081	2,013
Derivative Liabilities	589
Quoted Prices in Active Markets (Level 1) [Member]
Carrying value and estimated fair value of financial instruments
Interest rate swap derivative assets	0	0
Restricted investments:
Guaranteed Investment Contract	0	0
Guaranteed Repurchase Agreements	0	0
Rabbi Trust	8,941	5,898
Fixed income securities	0	0
Derivative Liabilities	0
Significant Other Observable Inputs (Level 2) [Member]
Carrying value and estimated fair value of financial instruments
Interest rate swap derivative assets	7,256	7,440
Restricted investments:
Guaranteed Investment Contract	5,742	5,742
Guaranteed Repurchase Agreements	41,590	33,821
Rabbi Trust	0	2,118
Fixed income securities	2,081	2,013
Derivative Liabilities	589
Significant Unobservable Inputs (Level 3) [Member]
Carrying value and estimated fair value of financial instruments
Interest rate swap derivative assets	0	0
Restricted investments:
Guaranteed Investment Contract	0	0
Guaranteed Repurchase Agreements	0	0
Rabbi Trust	0	0
Fixed income securities	0	0
Derivative Liabilities	$ 0