Long Term Investments Long Term Investments Equity Method Investments (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	$ 16,499	$ 10,954
Equity Method Investments [Roll Forward]
Distributions	8,450	3,539	6,730
Equity (loss) income on long-term investments accounted for under the equity method	19,966	23,963	15,213
Hedge Funds [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	16,499	10,954
Equity Method Investments [Roll Forward]
Equity Method Investments, Beginning Balance	10,954	0
Contributions	10,000	5,000
Distributions	0	0
Revision for partnership now accounted for under the equity method	0	3,350
Equity (loss) income on long-term investments accounted for under the equity method	(859)	1,489
Unrealized gains reclassified into net income	0	0
Unrealized gain on long-term investments	(3,596)	1,115
Net unrealized (loss) gain on long-term investments	(3,596)	1,115
Equity Method Investments, Ending Balance	$ 16,499	$ 10,954