Schedule II Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Allowance for Bad Debts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Jan. 1	$ 54,563		$ 56,103		$ 64,239
Charged to Costs and Expenses	44,521		44,068		49,023
Charged to Other Accounts	15,636	[1]	15,202	[1]	21,869	[1]
Deductions from Reserves	56,155	[2]	60,810	[2]	79,028	[2]
Balance at Dec. 31	58,565		54,563		56,103
NOL and Tax Credit Valuation Allowances [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Jan. 1	1,927		9,324		2,044
Charged to Costs and Expenses	4,379		240		7,280
Charged to Other Accounts	0		0		0
Deductions from Reserves	623	[3]	7,637	[3]	0	[3]
Balance at Dec. 31	$ 5,683		$ 1,927		$ 9,324

[1] Recovery of amounts previously written off as related to allowance for bad debts.

[2] Principally bad debts written off or transferred as related to allowance for bad debts.

[3] Reductions to valuation allowances for NOL and tax credit carryforwards primarily due to changes in tax laws and expirations of certain carryforwards.