Investment in Securities, Part II (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	$ 16,036,000	$ 18,085,000	$ 16,036,000	$ 18,085,000	$ 17,849,000
Gross unrealized gains	43,274,000	30,723,000	43,274,000	30,723,000	37,245,000
Gross unrealized losses	0	0	0	0	(28,000)
Total available for sale securities	33,912,000	33,625,000	33,912,000	33,625,000	35,187,000
Unrealized changes to fair value net of taxes included in other comprehensive income	(2,938,000)	7,906,000	(3,816,000)	6,969,000
Return of capital on available for sale securities			(1,650,000)	(1,262,000)
Proceeds from sale of investment available for sale			3,068,000	5,685,000
Investments classified as available for sale unrealized loss position [Abstract]
Number of investment holding in loss positions	0	1	0	1	1
Investment holding impairment period (in months)	0M	4M	0M	4M	7M
Losses on available-for-sale investments deemed other than temporary	0	0	20,000	0
Common Stock [Member]
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	14,931,000	16,724,000	14,931,000	16,724,000	16,487,000
Gross unrealized gains	17,308,000	15,179,000	17,308,000	15,179,000	16,795,000
Gross unrealized losses	0	0	0	0	0
Total available for sale securities	32,239,000	31,903,000	32,239,000	31,903,000	33,282,000
Closed-end Funds [Member]
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	36,721,000	38,116,000	36,721,000	38,116,000	37,104,000
Gross unrealized gains	24,010,000	14,040,000	24,010,000	14,040,000	18,779,000
Gross unrealized losses	0	0	0	0	(28,000)
Total available for sale securities	60,731,000	52,156,000	60,731,000	52,156,000	55,855,000
Mutual Funds [Member]
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	3,185,000	3,602,000	3,185,000	3,602,000	3,575,000
Gross unrealized gains	1,956,000	1,504,000	1,956,000	1,504,000	1,671,000
Gross unrealized losses	0	0	0	0	0
Total available for sale securities	5,141,000	5,106,000	5,141,000	5,106,000	5,246,000
Investments classified as available for sale unrealized loss position [Abstract]
Cost	0	100,000	0	100,000	101,000
Unrealized Losses	0	(21,000)	0	(21,000)	(28,000)
Fair Value	$ 0	$ 79,000	$ 0	$ 79,000	$ 73,000