Permanent Equity (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended			6 Months Ended									1 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Total stockholder's equity [Member]	Jun. 30, 2012 Accumulated other comprehensive income (loss) [Member]	Jun. 30, 2011 Accumulated other comprehensive income (loss) [Member]	Jun. 30, 2012 Additional paid-in capital [Member]	Jun. 30, 2011 Additional paid-in capital [Member]	Jun. 30, 2012 Noncontrolling Interest [Member]	Jun. 30, 2011 Noncontrolling Interest [Member]	Jun. 30, 2012 Additional Units Surrendered (Net of Acquisitions) [Member]	Jun. 30, 2012 UIS Agreement [Member]	Jan. 31, 2012 JVB Financial Holdings LLC [Member]	Jan. 31, 2011 JVB Financial Holdings LLC [Member]	Jun. 30, 2012 JVB Financial Holdings LLC [Member]
Permanent Equity (Textual) [Abstract]
Units issued by operating LLC to IFMI											651,285	464,946
Common stock held as treasury stock	50,400		50,400
Vesting of shares	239,259												186,339
Shares issued in connection with the redemption of Operating LLC units	186,339													559,020	186,339
Acquisition / (surrender) of additional units of consolidated subsidiary, net	$ 828	$ 972		$ 800	$ (28)	$ (27)	$ 828	$ 972	$ (800)	$ (945)
Permanent Equity (Additional Textual) [Abstract]
Ratio of Common Stock to membership units	1