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
Reserves for Accounts Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 5,232		$ 10,579		$ 11,270
Charged to operations	16,165	[1]	22,657	[1]	21,566	[1]
Other	(420)	[2]	(301)	[2]	(716)	[2]
Deductions	(16,422)	[3]	(27,703)	[3]	(21,541)	[3]
Balance at end of period	4,555		5,232		10,579
Deferred Tax Asset Valuation Allowance [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	7,407		7,086		7,096
Charged to operations	(6,974)	[4]	465		(10)
Other	0		0		0
Deductions	0		(144)		0
Balance at end of period	$ 433		$ 7,407		$ 7,086

[1] Amounts represent charges to bad debt expense and reductions to revenue for increases to the allowance for doubtful accounts and to the reserve for cash-basis customers.

[2] Amounts represent write-offs of account receivables previously reserved.

[3] Amounts represent cash collections from customers for accounts previously reserved and write-offs of accounts receivable recorded against the allowance for doubtful accounts or the reserve for cash-basis customers.

[4] Amount represents the reversal of a tax valuation allowance related to NOL carryforwards not expected to be realized.