Schedule II - Valuation And Qualifying Accounts (Details) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 14,900,000		$ 18,700,000		$ 48,900,000
Charges	3,100,000		3,100,000		2,400,000
Deductions	(2,800,000)		(4,700,000)
Deductions	(6,500,000)		(6,900,000)		(32,600,000)
Balance at End of Period	11,500,000		14,900,000		18,700,000
Change in net unrealized holding gain (loss) recorded in other comprehensive income			100,000		4,000,000
Other-than-temporary impairment losses	574,000		1,164,000		6,119,000
Allowance For Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	8,500,000		10,300,000		11,600,000
Charges	2,000,000	[1]	2,900,000	[1]	2,400,000	[1]
Deductions	(2,800,000)	[2]	(4,700,000)	[2]	(3,700,000)	[2]
Balance at End of Period	7,700,000		8,500,000		10,300,000
Unrealized Losses On Securities Available For Sale [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	800,000		3,000,000		13,100,000
Charges	700,000	[3]
Deductions	(500,000)	[4]	(2,200,000)	[5]	(10,100,000)	[6]
Balance at End of Period	1,000,000		800,000		3,000,000
Valuation Allowance For Deferred Tax Assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	5,600,000		5,400,000		24,200,000
Charges	400,000	[7]	200,000	[7]
Deductions	(3,200,000)	[8]			(18,800,000)	[8]
Balance at End of Period	2,800,000		5,600,000		5,400,000
Auction Rate Securities [Member] | Collateralized Debt Obligations Sold [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Reversal of unrealized losses on redeemed securities			$ 900,000

[1] Provision for doubtful accounts.

[2] Write-offs and reversals of uncollectible accounts.

[3] Unrealized losses and reductions to unrealized gains recorded in other comprehensive income.

[4] Represents reversal of unrealized losses upon redemption of security.

[5] Represents $1.2 million of credit and other losses recognized in earnings, $0.9 million of reversal of unrealized losses upon sale of securities and $0.1 million, net, of unrealized gains recognized in other comprehensive income.

[6] Represents $4.0 million of unrealized gains recorded in other comprehensive income, and $6.1 million of credit losses recognized in earnings.

[7] Increase in the foreign tax loss carryforward.

[8] Decrease in valuation allowance for deferred tax assets is due primarily to the utilization of tax loss carryforwards and other tax benefits.