Valuation and Qualifying Accounts (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Valuation and Qualifying Accounts Disclosure [Line Items]
Fair Value Inputs, Discount Rate	15.50%
Allowance for uncollectible accounts
Balance at the beginning of the period		$ 14,978	$ 13,801	$ 13,015
Charged to Costs and Expenses		6,396	6,742	7,366
Charged to other Accounts		0	0	0
Write-offs		5,134	6,178	7,237
Other		306	613	657
Balance at the End of the period	$ 16,546	$ 16,546	$ 14,978	$ 13,801