Investment in Securities, Summary of Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value I (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	$ 78,872	$ 38,178	$ 39,171
Gross unrealized gains	40,811	41,733	42,456
Gross unrealized losses	(62)	(65)	0
Total available for sale securities	119,621	79,846	81,627
Common Stock [Member]
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	13,578	13,637	15,009
Gross unrealized gains	23,851	25,305	24,325
Gross unrealized losses	0	0	0
Total available for sale securities	37,429	38,942	39,334
Closed-end Funds [Member]
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	62,780	21,962	21,531
Gross unrealized gains	14,864	14,398	15,607
Gross unrealized losses	(28)	(37)	0
Total available for sale securities	77,616	36,323	37,138
Mutual Funds [Member]
Available for Sale Securities, Cost, Gross Unrealized Gains, Gross Unrealized Losses and Fair Value [Abstract]
Cost	2,514	2,579	2,631
Gross unrealized gains	2,096	2,030	2,524
Gross unrealized losses	(34)	(28)	0
Total available for sale securities	$ 4,576	$ 4,581	$ 5,155