VALUATION AND QUALIFYING ACCOUNTS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
State [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses, valuation allowance	$ 1,141		$ 137		$ 264
Tax Credit Carryforward [Line Items]
Tax credits, valuation allowance	514				709
Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards [Line Items]
Net operating losses, valuation allowance	22,940
Tax Credit Carryforward [Line Items]
Tax credits, valuation allowance	6,408
Deferred Tax Valuation Account [Member]
Valuation and qualifying accounts [Roll forward]
Balance at Beginning of Period	10,845		10,708		9,735
Charged to costs and expenses	29,348	[1]
Charged To other Accounts	1,141	[2]	137	[3]	973	[4]
Deductions	(514)	[5]
Balance at End of Period	40,820		10,845		10,708
Allowance For Doubtful Accounts [Member]
Valuation and qualifying accounts [Roll forward]
Balance at Beginning of Period	14,464		13,907		14,482
Charged to costs and expenses	16,796		13,816		14,349
Charged To other Accounts	1,817		179		772
Deductions	(16,105)		(13,438)		(15,696)
Balance at End of Period	$ 16,972		$ 14,464		$ 13,907

[1] Adjustment to valuation allowance for federal net operating losses and federal credits of $22,940 and $6,408, respectively.

[2] Adjustment to valuation allowance for state net operating losses of $1,141.

[3] Adjustment to valuation allowance for state net operating losses of $137.

[4] Adjustment to valuation allowance for state net operating losses of $264. Establishment of valuation allowance against state tax credits of $709.

[5] Adjustment to valuation allowance for state credits of $514.