Long Term Investments Textuals (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		1 Months Ended
	Jul. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Long Term Investment [Member]	Jun. 30, 2011 Long Term Investment [Member]	Jun. 30, 2012 Long Term Investment [Member]	Jun. 30, 2011 Long Term Investment [Member]	Jun. 30, 2012 Long Term Investment [Member] Limited Partnership [Member]	Jun. 30, 2011 Long Term Investment [Member] Limited Partnership [Member]	Jun. 30, 2012 Long Term Investment [Member] Limited Partnership [Member]	Jun. 30, 2011 Long Term Investment [Member] Limited Partnership [Member]	Jan. 31, 2012 Hedge Funds [Member]	Apr. 30, 2011 Hedge Funds [Member]	Jun. 30, 2012 Hedge Funds [Member]	Dec. 31, 2011 Hedge Funds [Member]
Schedule of Equity Method Investments [Line Items]
Distributions from liquidation of long-term investments	$ 2,775	$ 207	$ 53,333	$ 207	$ 62,219
Gain recognized		135	19,475	135	23,611
Payments to acquire equity investments															5,000	10,000
Equity (loss) income on long-term investments							(1,215)	(154)	(1,329)	609	(1,215)	(154)	(1,329)	609
Equity Method Investments		$ 5,552		$ 5,552		$ 16,499											$ 5,552	$ 16,499