Discontinued Operations - Revenue and Expenses from Discontinued Operation (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
EXPENSES
Income attributable to noncontrolling interest before income taxes	$ 15,366	$ 3,731	[1]	$ 14,709	$ 7,768	[1]
OMHHF
REVENUE
Interest	472	717		809	1,049
Principal transactions, net	(1,541)	(1,831)		(6,628)	8,226
Gain on sale of assets	14,916	0		14,916	0
Other	4,070	12,082		12,558	10,079
Total revenue	17,917	10,968		21,655	19,354
EXPENSES
Compensation and related expenses	735	4,409		3,652	6,676
Communications and technology	59	100		161	196
Occupancy and equipment costs	286	74		362	150
Interest	159	399		380	540
Other	1,312	2,255		2,391	4,024
Total expenses	2,551	7,237		6,946	11,586
Income before income taxes	15,366	3,731		14,709	7,768
Income attributable to noncontrolling interest before income taxes	$ 2,508	$ 609		$ 2,401	$ 1,268

[1] Amounts have been recast to reflect discontinued operations. See Note 3 for details.