Inventories (Details) (USD $)	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Inventories, net [Abstract]
Raw materials and supplies	$ 51,522,000	$ 42,281,000
Work-in-process	28,639,000	38,420,000
Finished goods	154,521,000	143,648,000
Valuation reserves	(5,344,000)	(5,156,000)
Inventories	229,338,000	219,193,000
Possible effect of liquidation of LIFO layers on cost of goods sold	18,200,000
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