STOCK OWNERSHIP AND BENEFIT PLANS (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock-based compensation expense
Stock-based compensation expense before income taxes	$ 895	$ 4,443	$ 3,397	$ 3,501
Income tax benefit		(864)	(918)	(888)
Stock-based compensation expense, net of income taxes		3,579	2,479	2,613
Earnings per share impact:
Basic - net income (in dollars per share)		$ 0.27	$ 0.19	$ 0.20
Diluted - net income (in dollars per share)		$ 0.27	$ 0.19	$ 0.20
Expenses associated with management retirements	3,000
Cost of products sold
Stock-based compensation expense
Stock-based compensation expense before income taxes		324	261	316
General and administrative expenses
Stock-based compensation expense
Stock-based compensation expense before income taxes		3,018	2,431	2,402
Selling and distribution expenses
Stock-based compensation expense
Stock-based compensation expense before income taxes		$ 1,101	$ 705	$ 783