FAIR VALUE MEASUREMENTS (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term Debt, Fair Value	$ 820,900,000		$ 820,900,000		$ 538,500,000
Marketable securities	11,113,000		11,113,000		111,000
Auction rate securities	4,326,000		4,326,000		4,245,000
Unrealized pre-tax gain (loss) on auction rate securities			100,000
Temporary decline in fair value of securities	400,000		400,000
Total | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities	11,113,000		11,113,000		111,000
Auction rate securities	4,326,000		4,326,000		4,245,000
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Auction rate securities
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities
Auction rate securities
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Marketable securities
Changes in the entity's auction rate securities measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Balance at the beginning of the period	4,326,000	5,311,000	4,245,000	5,437,000
Sale of auction rate securities	0	(1,000,000)	0	(1,000,000)
Unrealized (losses) gains included in other comprehensive income	0	(72,000)	81,000	(198,000)
Balance at the end of the period	$ 4,326,000	$ 4,239,000	$ 4,326,000	$ 4,239,000