Long Term Investments Textuals (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		1 Months Ended				1 Months Ended
	Sep. 30, 2011	Sep. 30, 2012 investments	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Long Term Investment [Member]	Sep. 30, 2011 Long Term Investment [Member]	Sep. 30, 2012 Long Term Investment [Member]	Sep. 30, 2011 Long Term Investment [Member]	Sep. 30, 2012 Long Term Investment [Member] Limited Partnership [Member]	Sep. 30, 2011 Long Term Investment [Member] Limited Partnership [Member]	Sep. 30, 2012 Long Term Investment [Member] Limited Partnership [Member]	Sep. 30, 2011 Long Term Investment [Member] Limited Partnership [Member]	Jan. 31, 2012 Hedge Funds [Member]	Apr. 30, 2011 Hedge Funds [Member]	Sep. 30, 2012 Hedge Funds [Member]	Dec. 31, 2011 Hedge Funds [Member]	Jun. 30, 2012 Real estate partnership [Member]
Schedule of Equity Method Investments [Line Items]
Distributions from liquidation of long-term investments	$ 3,971		$ 66,190														$ 207
Gain recognized	2,221		25,832														135
Number of investments liquidated		2
Payments to acquire equity investments													5,000	10,000
Equity income (loss) on long-term investments					124	(1,699)	(1,205)	(1,090)	124	(1,699)	(1,205)	(1,090)
Equity Method Investments		$ 6,152		$ 16,499											$ 6,152	$ 16,499