Allowance for Uncollectible Accounts (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Allowance for uncollectible accounts activity and ending balances
Beginning of year balance			$ 10,692
Additions and Expenses	2,647	3,143	5,408	5,704
Deductions			(5,191)
End of Period Balance	$ 10,909		$ 10,909