FAIR VALUE MEASUREMENTS (Details) (USD $)	12 Months Ended																											12 Months Ended		3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure [Member]	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure [Member] Commercial paper [Member]	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure [Member] Money market funds [Member]	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure [Member] Money market funds [Member]	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure [Member] Certificates of deposit [Member]	Dec. 31, 2012 Estimate of Fair Value, Fair Value Disclosure [Member] Corporate securities [Member]	Dec. 31, 2011 Estimate of Fair Value, Fair Value Disclosure [Member] Corporate securities [Member]	Dec. 31, 2012 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	Dec. 31, 2011 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]	Dec. 31, 2011 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Commercial paper [Member]	Dec. 31, 2012 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Money market funds [Member]	Dec. 31, 2011 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Money market funds [Member]	Dec. 31, 2011 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Certificates of deposit [Member]	Dec. 31, 2012 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Corporate securities [Member]	Dec. 31, 2011 Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] Corporate securities [Member]	Dec. 31, 2012 Significant Other Observable Inputs (Level 2) [Member]	Dec. 31, 2011 Significant Other Observable Inputs (Level 2) [Member]	Dec. 31, 2011 Significant Other Observable Inputs (Level 2) [Member] Commercial paper [Member]	Dec. 31, 2012 Significant Other Observable Inputs (Level 2) [Member] Money market funds [Member]	Dec. 31, 2011 Significant Other Observable Inputs (Level 2) [Member] Money market funds [Member]	Dec. 31, 2011 Significant Other Observable Inputs (Level 2) [Member] Certificates of deposit [Member]	Dec. 31, 2012 Significant Other Observable Inputs (Level 2) [Member] Corporate securities [Member]	Dec. 31, 2011 Significant Other Observable Inputs (Level 2) [Member] Corporate securities [Member]	Dec. 31, 2012 Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2011 Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Semi South [Member]	Mar. 31, 2012 Semi South [Member]	Dec. 31, 2012 Semi South [Member] Significant Unobservable Inputs (Level 3) [Member]	Sep. 30, 2012 Contingent Purchase Commitment [Member] Semi South [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchase Options Other																															$ 6,200,000
Investments, Fair Value Disclosure						9,849,000	7,140,000	30,190,000	10,000,000	31,766,000	62,940,000			0	7,140,000	30,190,000	0	0	0			9,849,000	0	0	10,000,000	31,766,000	62,940,000
Assets, Fair Value Disclosure				38,906,000	112,979,000							7,140,000	30,190,000							31,766,000	82,789,000
Asset Impairment Charges	33,745,000	0	0																											33,700,000
Fair Value of Purchase Option on SemiSouth Loan																																	0
Initial Loan to SemiSouth																															18,000,000
Fair value of note receivable																																13,400,000
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance																												0	0
Purchases and issuances																												13,433,000	3,000,000
Settlements																												(13,433,000)	(3,000,000)
Ending balance																												0	0
Investment Income, Amortization of Discount																																$ 1,600,000