Inventories (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2012	Jun. 29, 2013	Dec. 31, 2011	Dec. 29, 2012
Inventories [Abstract]
Raw materials and supplies		$ 33,382,000		$ 46,114,000
Work-in-process		45,992,000		40,951,000
Finished goods		150,255,000		148,014,000
Valuation reserves		(6,804,000)		(5,645,000)
Inventories		222,825,000		229,434,000
Possible effect of liquidation of LIFO layers on cost of goods sold		4,600,000
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