Valuation (Fair Value Measurement Using Significant Unobservable Inputs) (Details) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	$ 519,647	$ 514,536	$ 493,541	$ 638,486
Assets, Accreted Discounts/Amortized Premiums	(4,295)	44	(8,533)	(3,049)
Assets, Realized Gain (Loss)	6,250	3,858	4,578	13,603
Assets, Change In Net Unrealized Gain/(Loss)	(3,188)	32	(9,151)	(6,856)
Assets, Purchases	106,972	151,048	221,133	263,005
Assets, Sales	(110,295)	(133,371)	(184,698)	(298,776)
Assets, Transfers into Level 3	12,823	20,165	11,261	6,490
Assets, Transfers out of Level 3	(8,790)	(21,038)	(9,007)	(77,629)
Assets, Ending Balance	519,124	535,274	519,124	535,274
Liabilities, Begining Balance	(4,540)	(1,215)	(6,159)	(1,013)
Liabilities, Accreted Discounts/Amortized Premiums	(9)	0	(8)	(2)
Liabilities, Realized Gain/(Loss)	(2,007)	330	(3,913)	311
Liabilities, Change In Net Unrealized Gain/(Loss)	(323)	(1,636)	3,628	(1,924)
Liabilities Purchases/Payments	12,716	(340)	15,941	(252)
Liabilities, Sales/Issuance	(17,346)	23	(20,998)	42
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(11,509)	(2,838)	(11,509)	(2,838)
Change in net unrealized gain (loss) on investments Level 3 Held At End of Period	(2,200)	(600)	(10,900)	(1,000)
Unrealized Gain (Loss) On Investments Sold Short, Level 3, Held At End Of Period	(30)		(40)
Change in net unrealized gain (loss) in financial derivative assets Level 3 Held At End of Period	300	1,200	900	1,000
Change in net unrealized Gain (Loss) on financial derivative liabilities Level 3 Held At End of Period	(600)	(1,700)	(100)	(1,900)
Change in net unrealized gain (loss) in securitized debt Level 3 Held At End of Period		1		20
Change in net unrealized Gain (Loss) On Guarantees Level 3 Held At End Of Period	300		500
Securitized Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance		(669)		(774)
Liabilities, Accreted Discounts/Amortized Premiums		0		(2)
Liabilities, Realized Gain/(Loss)		0		0
Liabilities, Change In Net Unrealized Gain/(Loss)		1		20
Liabilities, Payments		13		101
Liabilities, Issuances		0		0
Liabilities, Transfers into Level 3		0		0
Liabilities, Transfers out of Level 3		0		0
Liabilities, Ending Balance		(655)		(655)
Guarantees [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(616)		(828)
Liabilities, Accreted Discounts/Amortized Premiums	0		0
Liabilities, Realized Gain/(Loss)	0		0
Liabilities, Change In Net Unrealized Gain/(Loss)	304		516
Liabilities, Payments	0		0
Liabilities, Issuances	0		0
Liabilities, Transfers into Level 3	0		0
Liabilities, Transfers out of Level 3	0		0
Liabilities, Ending Balance	(312)		(312)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	512,246	503,509	486,974	626,999
Assets, Accreted Discounts/Amortized Premiums	(4,295)	44	(8,533)	(3,049)
Assets, Realized Gain (Loss)	2,465	5,136	4,267	14,480
Assets, Change In Net Unrealized Gain/(Loss)	(2,789)	(1,154)	(9,635)	(7,805)
Assets, Purchases	110,142	151,024	220,698	262,959
Assets, Sales	(109,670)	(132,208)	(183,893)	(296,967)
Assets, Transfers into Level 3	12,823	20,165	11,261	6,490
Assets, Transfers out of Level 3	(8,790)	(21,038)	(9,007)	(77,629)
Assets, Ending Balance	512,132	525,478	512,132	525,478
Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	22,306	26,335	24,918	31,385
Assets, Accreted Discounts/Amortized Premiums	(1,888)	(1,941)	(3,945)	(3,947)
Assets, Realized Gain (Loss)	(82)	0	(90)	472
Assets, Change In Net Unrealized Gain/(Loss)	(133)	1,604	(679)	1,508
Assets, Purchases	303	6,317	302	7,506
Assets, Sales	0	(1,930)	0	(6,539)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	20,506	30,385	20,506	30,385
Investments [Member] | Private Label Residential Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	113,382	169,371	116,435	274,369
Assets, Accreted Discounts/Amortized Premiums	1,109	1,824	1,517	4,692
Assets, Realized Gain (Loss)	(290)	4,423	(283)	11,397
Assets, Change In Net Unrealized Gain/(Loss)	(1,310)	(40)	(2,370)	(3,889)
Assets, Purchases	1,687	40,761	7,419	58,464
Assets, Sales	(6,100)	(55,420)	(12,461)	(113,848)
Assets, Transfers into Level 3	12,823	20,165	11,261	6,490
Assets, Transfers out of Level 3	(8,790)	(21,038)	(9,007)	(77,629)
Assets, Ending Balance	112,511	160,046	112,511	160,046
Investments [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	35,350	52,214	34,145	53,311
Assets, Accreted Discounts/Amortized Premiums	431	556	886	1,928
Assets, Realized Gain (Loss)	0	(91)	322	523
Assets, Change In Net Unrealized Gain/(Loss)	(839)	(792)	(3,840)	(2,692)
Assets, Purchases	0	4,538	7,844	20,132
Assets, Sales	0	(6,591)	(4,415)	(23,368)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	34,942	49,834	34,942	49,834
Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	56,365	38,918	66,399	28,309
Assets, Accreted Discounts/Amortized Premiums	727	736	1,272	1,275
Assets, Realized Gain (Loss)	(1)	0	182	0
Assets, Change In Net Unrealized Gain/(Loss)	(671)	(637)	223	(620)
Assets, Purchases	0	26,519	13,424	50,810
Assets, Sales	(6,954)	(10,226)	(32,034)	(24,464)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	49,466	55,310	49,466	55,310
Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	35,580	30,845	22,089	27,482
Assets, Accreted Discounts/Amortized Premiums	141	405	248	848
Assets, Realized Gain (Loss)	757	1,422	865	1,664
Assets, Change In Net Unrealized Gain/(Loss)	(147)	(215)	127	(70)
Assets, Purchases	17,101	3,782	32,066	9,758
Assets, Sales	(6,783)	(15,310)	(8,746)	(18,753)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	46,649	20,929	46,649	20,929
Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	34,415	88,847	45,974	123,338
Assets, Accreted Discounts/Amortized Premiums	(1,942)	149	(2,869)	(4,473)
Assets, Realized Gain (Loss)	(279)	(819)	801	(48)
Assets, Change In Net Unrealized Gain/(Loss)	145	252	417	(1,453)
Assets, Purchases	1,178	39,110	1,178	49,587
Assets, Sales	(408)	(29,151)	(12,392)	(68,563)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	33,109	98,388	33,109	98,388
Investments [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	143,854	34,773	115,376	22,950
Assets, Accreted Discounts/Amortized Premiums	(2,713)	(1,701)	(5,596)	(3,419)
Assets, Realized Gain (Loss)	6	0	6	0
Assets, Change In Net Unrealized Gain/(Loss)	(655)	225	(549)	776
Assets, Purchases	37,046	25,082	88,956	41,139
Assets, Sales	(23,143)	(5,922)	(43,798)	(8,989)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	154,395	52,457	154,395	52,457
Investments [Member] | Corporate Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	24,552	31,836	27,028	42,708
Assets, Accreted Discounts/Amortized Premiums	(160)	16	(46)	47
Assets, Realized Gain (Loss)	275	(78)	255	108
Assets, Change In Net Unrealized Gain/(Loss)	1,874	(1,809)	(2,102)	(2,390)
Assets, Purchases	49,353	1,025	52,320	12,630
Assets, Sales	(38,920)	(4,712)	(40,481)	(26,825)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	36,974	26,278	36,974	26,278
Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	21,843	9,070	12,522	8,635
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	1,978	164	2,238	248
Assets, Change In Net Unrealized Gain/(Loss)	(1,750)	(10)	(331)	527
Assets, Purchases	884	2,774	10,672	5,245
Assets, Sales	(18,793)	(2,496)	(20,939)	(5,153)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	4,162	9,502	4,162	9,502
Investments [Member] | Private Corporate Equity Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	24,599	21,300	22,088	14,512
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	101	115	(29)	116
Assets, Change In Net Unrealized Gain/(Loss)	697	268	(531)	498
Assets, Purchases	2,590	1,116	6,517	7,688
Assets, Sales	(8,569)	(450)	(8,627)	(465)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	19,418	22,349	19,418	22,349
Financial Derivatives - Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	7,401	11,027	6,567	11,487
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	3,785	(1,278)	311	(877)
Assets, Change In Net Unrealized Gain/(Loss)	(399)	1,186	484	949
Assets, Purchases	(3,170)	24	435	46
Assets, Sales	(625)	(1,163)	(805)	(1,809)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	6,992	9,796	6,992	9,796
Financial Derivatives - Assets [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	6,227	10,809	6,332	11,387
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	373	(1,563)	464	(1,162)
Assets, Change In Net Unrealized Gain/(Loss)	(149)	1,056	(255)	701
Assets, Purchases	(24)	3	12	25
Assets, Sales	(359)	(856)	(485)	(1,502)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	6,068	9,449	6,068	9,449
Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	1,074	118	85	0
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	3,412	285	(103)	285
Assets, Change In Net Unrealized Gain/(Loss)	(250)	130	739	248
Assets, Purchases	(3,146)	21	423	21
Assets, Sales	(266)	(307)	(320)	(307)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	824	247	824	247
Financial Derivatives - Assets [Member] | Warrant [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	100	100	150	100
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	0	0	(50)	0
Assets, Change In Net Unrealized Gain/(Loss)	0	0	0	0
Assets, Purchases	0	0	0	0
Assets, Sales	0	0	0	0
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	100	100	100	100
Financial Derivatives - Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(895)	(546)	(4,883)	(239)
Liabilities, Accreted Discounts/Amortized Premiums	0	0	0	0
Liabilities, Realized Gain/(Loss)	(2,178)	330	(4,444)	311
Liabilities, Change In Net Unrealized Gain/(Loss)	(318)	(1,637)	3,670	(1,944)
Liabilities, Purchases	2,348	(353)	4,686	(353)
Liabilities, Sales	(207)	23	(279)	42
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(1,250)	(2,183)	(1,250)	(2,183)
Financial Derivatives - Liabilities [Member] | Credit Default Swaps On Asset Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(220)	(239)	(221)	(239)
Liabilities, Accreted Discounts/Amortized Premiums	0	0	0	0
Liabilities, Realized Gain/(Loss)	(63)	(23)	(79)	(42)
Liabilities, Change In Net Unrealized Gain/(Loss)	24	(41)	24	(41)
Liabilities, Purchases	0	0	0	0
Liabilities, Sales	25	23	42	42
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(234)	(280)	(234)	(280)
Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(675)	(307)	(4,662)	0
Liabilities, Accreted Discounts/Amortized Premiums	0	0	0	0
Liabilities, Realized Gain/(Loss)	(2,115)	353	(4,365)	353
Liabilities, Change In Net Unrealized Gain/(Loss)	(342)	(1,596)	3,646	(1,903)
Liabilities, Purchases	2,348	(353)	4,686	(353)
Liabilities, Sales	(232)	0	(321)	0
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(1,016)	$ (1,903)	(1,016)	$ (1,903)
Securities Sold Short - Securities Sold, Not Yet Purchased [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(3,029)		(448)
Liabilities, Accreted Discounts/Amortized Premiums	(9)		(8)
Liabilities, Realized Gain/(Loss)	171		531
Liabilities, Change In Net Unrealized Gain/(Loss)	(309)		(558)
Liabilities, Purchases	10,368		11,255
Liabilities, Sales	(17,139)		(20,719)
Liabilities, Transfers into Level 3	0		0
Liabilities, Transfers out of Level 3	0		0
Liabilities, Ending Balance	(9,947)		(9,947)
Securities Sold Short - Securities Sold, Not Yet Purchased [Member] | Corporate Debt Sold Short [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(3,029)		(448)
Liabilities, Accreted Discounts/Amortized Premiums	(9)		(8)
Liabilities, Realized Gain/(Loss)	171		531
Liabilities, Change In Net Unrealized Gain/(Loss)	(309)		(558)
Liabilities, Purchases	10,368		11,255
Liabilities, Sales	(17,139)		(20,719)
Liabilities, Transfers into Level 3	0		0
Liabilities, Transfers out of Level 3	0		0
Liabilities, Ending Balance	$ (9,947)		$ (9,947)