Inventories (Details) (USD $)	12 Months Ended
	Dec. 29, 2012	Dec. 31, 2011
Inventories [Abstract]
Raw materials and supplies	$ 46,114,000	$ 42,281,000
Work-in-process	40,951,000	38,420,000
Finished goods	148,014,000	143,648,000
Valuation reserves	(5,645,000)	(5,156,000)
Inventories	229,434,000	219,193,000
Inventories valued using the LIFO method	19,900,000	15,100,000
FIFO cost of inventories	109,800,000	101,200,000
Average cost basis inventories	51,400,000	44,900,000
Deferred LIFO Gain	8,000,000
Effect of liquidation of LIFO layers on cost of sales	8,000,000
Effect of liquidation of LIFO layers per diluted share after tax (in dollars per share)	$ 0.13
FIFO value of inventory consigned to others	$ 4,500,000	$ 2,900,000