Fair Value Disclosures (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	$ 166,192	$ 124,546
Other investments, Carrying Value	37,609	42,772
Trading securities sold, not yet purchased	84,119	99,613
Investments-trading [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	166,192	124,546
Investments-trading [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	20,790	9,472
Investments-trading [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	145,154	109,886
Investments-trading [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	248	5,188
Investments-trading [Member] | U.S. government agency MBS and CMOs [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	30,685	7,563
Investments-trading [Member] | U.S. government agency MBS and CMOs [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	30,685	7,563
Investments-trading [Member] | U.S. government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	34,452	14,600
Investments-trading [Member] | U.S. government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	66	144
Investments-trading [Member] | U.S. government agency debt securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	34,386	14,456
Investments-trading [Member] | RMBS [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	1,178	7,108
Investments-trading [Member] | RMBS [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	1,178	2,176
Investments-trading [Member] | RMBS [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading		4,932
Investments-trading [Member] | CMBS [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading		1,587
Investments-trading [Member] | CMBS [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading		1,587
Investments-trading [Member] | U.S. Treasury securities [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	7,473	8,524
Investments-trading [Member] | U.S. Treasury securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	7,473	8,524
Investments-trading [Member] | Interests in securitizations [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	259	608
Investments-trading [Member] | Interests in securitizations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	74	387
Investments-trading [Member] | Interests in securitizations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	185	221
Investments-trading [Member] | SBA loans [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	4,382	9,049
Investments-trading [Member] | SBA loans [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	4,382	9,049
Investments-trading [Member] | Corporate bonds and redeemable preferred stock [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	55,226	65,445
Investments-trading [Member] | Corporate bonds and redeemable preferred stock [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	3,850	779
Investments-trading [Member] | Corporate bonds and redeemable preferred stock [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	51,376	64,666
Investments-trading [Member] | Foreign government bonds [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	99	67
Investments-trading [Member] | Foreign government bonds [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	99	67
Investments-trading [Member] | Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	18,895	9,225
Investments-trading [Member] | Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	18,895	9,225
Investments-trading [Member] | Exchange traded funds [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	9,377
Investments-trading [Member] | Exchange traded funds [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	9,377
Investments-trading [Member] | Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	4,079	710
Investments-trading [Member] | Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	4,079	710
Investments-trading [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	87	60
Investments-trading [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	24	25
Investments-trading [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Total investments-trading	63	35
Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,609	42,772
Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	90	24
Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	229
Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,290	42,748
Other investments, at fair value [Member] | Interests in securitizations [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	97	88
Other investments, at fair value [Member] | Interests in securitizations [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	97	88
Other investments, at fair value [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,217	42,417
Other investments, at fair value [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	24	24
Other investments, at fair value [Member] | Equity securities [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,193	42,393
Other investments, at fair value [Member] | Residential loans [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	229	267
Other investments, at fair value [Member] | Residential loans [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	229
Other investments, at fair value [Member] | Residential loans [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value		267
Other investments, at fair value [Member] | Foreign currency forward contracts [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	66
Other investments, at fair value [Member] | Foreign currency forward contracts [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	66
Trading securities sold, not yet purchased [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	84,119	99,613
Trading securities sold, not yet purchased [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	12,760	12,839
Trading securities sold, not yet purchased [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	71,359	86,774
Trading securities sold, not yet purchased [Member] | U.S. government agency MBS [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	47	16
Trading securities sold, not yet purchased [Member] | U.S. government agency MBS [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	47	16
Trading securities sold, not yet purchased [Member] | U.S. Treasury securities [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	10,811	11,755
Trading securities sold, not yet purchased [Member] | U.S. Treasury securities [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	10,811	11,755
Trading securities sold, not yet purchased [Member] | Corporate bonds and redeemable preferred stock [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	64,651	87,537
Trading securities sold, not yet purchased [Member] | Corporate bonds and redeemable preferred stock [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	313	1,084
Trading securities sold, not yet purchased [Member] | Corporate bonds and redeemable preferred stock [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	64,338	86,453
Trading securities sold, not yet purchased [Member] | Foreign government bonds [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	23	158
Trading securities sold, not yet purchased [Member] | Foreign government bonds [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	23	158
Trading securities sold, not yet purchased [Member] | Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	122	143
Trading securities sold, not yet purchased [Member] | Municipal bonds [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	122	143
Trading securities sold, not yet purchased [Member] | Exchange traded funds [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	1,636
Trading securities sold, not yet purchased [Member] | Exchange traded funds [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	1,636
Trading securities sold, not yet purchased [Member] | Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	6,829	4
Trading securities sold, not yet purchased [Member] | Certificates of deposit [Member] | Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Trading securities sold, not yet purchased	6,829	4
Other securities [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	112	156
Other securities [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices In Active Markets (Level 1) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	24	24
Other securities [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	88	132
Other Investment Vehicles [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,105	42,261
Other Investment Vehicles [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,105	42,261
Other Investment Vehicles [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	37,105	42,261
Other Investment Vehicles [Member] | EuroDekania [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	2,103	2,370
Other Investment Vehicles [Member] | EuroDekania [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	2,103	2,370
Other Investment Vehicles [Member] | EuroDekania [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	2,103	2,370
Other Investment Vehicles [Member] | Star Asia [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	32,299	37,358
Other Investment Vehicles [Member] | Star Asia [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	32,299	37,358
Other Investment Vehicles [Member] | Star Asia [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	32,299	37,358
Other Investment Vehicles [Member] | Tiptree Financial Partners L.P. [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	2,703	2,533
Other Investment Vehicles [Member] | Tiptree Financial Partners L.P. [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	2,703	2,533
Other Investment Vehicles [Member] | Tiptree Financial Partners L.P. [Member] | Other investments, at fair value [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Schedule of fair value, assets and liabilities measured on recurring basis
Other investments, Carrying Value	$ 2,703	$ 2,533