Valuation (Fair Value Measurement Using Significant Unobservable Inputs) (Details) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	$ 514,536	$ 694,403	$ 638,486	$ 756,934
Assets, Accreted Discounts/Amortized Premiums	44	3,014	(3,049)	7,037
Assets, Realized Gain (Loss)	3,858	12,574	13,603	38,056
Assets, Change In Net Unrealized Gain/(Loss)	32	2,273	(6,856)	(9,700)
Assets, Purchases	151,048	141,089	263,005	305,047
Assets, Sales	(133,371)	(145,260)	(298,776)	(389,281)
Assets, Transfers into Level 3	20,165	0	6,490	0
Assets, Transfers out of Level 3	(21,038)	0	(77,629)	0
Assets, Ending Balance	535,274	708,093	535,274	708,093
Liabilities, Begining Balance	(1,215)	(1,333)	(1,013)	(1,333)
Liabilities, Accreted Discounts/Amortized Premiums	0	(5)	(2)	(12)
Liabilities, Realized Gain/(Loss)	330	(20)	311	(39)
Liabilities, Change In Net Unrealized Gain/(Loss)	(1,636)	1	(1,924)	(16)
Liabilities Purchases/Payments	(340)	62	(252)	86
Liabilities, Sales/Issuance	23	20	42	39
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(2,838)	(1,275)	(2,838)	(1,275)
Change in net unrealized gain (loss) on investments	(600)	6,000	(1,000)	6,200
Change in net unrealized gain (loss) in financial derivative assets	1,200	600	1,000	(1,500)
Change in net unrealized Gain (Loss) on financial derivative liabilities	(1,700)		(1,900)
Change in net unrealized gain (loss) in securitized debt	1	1	20	(16)
Securitized Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(669)	(983)	(774)	(983)
Liabilities, Accreted Discounts/Amortized Premiums	0	(5)	(2)	(12)
Liabilities, Realized Gain/(Loss)	0	0	0	0
Liabilities, Change In Net Unrealized Gain/(Loss)	1	1	20	(16)
Liabilities, Payments	13	62	101	86
Liabilities, Issuances	0	0	0	0
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(655)	(925)	(655)	(925)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	503,509	679,229	626,999	740,288
Assets, Accreted Discounts/Amortized Premiums	44	3,014	(3,049)	7,037
Assets, Realized Gain (Loss)	5,136	13,041	14,480	37,332
Assets, Change In Net Unrealized Gain/(Loss)	(1,154)	1,687	(7,805)	(9,075)
Assets, Purchases	151,024	140,672	262,959	304,591
Assets, Sales	(132,208)	(143,712)	(296,967)	(386,242)
Assets, Transfers into Level 3	20,165	0	6,490	0
Assets, Transfers out of Level 3	(21,038)	0	(77,629)	0
Assets, Ending Balance	525,478	693,931	525,478	693,931
Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	26,335	41,375	31,385	40,504
Assets, Accreted Discounts/Amortized Premiums	(1,941)	(2,045)	(3,947)	(4,334)
Assets, Realized Gain (Loss)	0	135	472	170
Assets, Change In Net Unrealized Gain/(Loss)	1,604	(728)	1,508	23
Assets, Purchases	6,317	0	7,506	2,554
Assets, Sales	(1,930)	(2,497)	(6,539)	(2,677)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	30,385	36,240	30,385	36,240
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	169,371	490,083	274,369	580,772
Assets, Accreted Discounts/Amortized Premiums	1,824	5,203	4,692	10,589
Assets, Realized Gain (Loss)	4,423	7,718	11,397	31,178
Assets, Change In Net Unrealized Gain/(Loss)	(40)	3,516	(3,889)	(9,336)
Assets, Purchases	40,761	64,639	58,464	154,223
Assets, Sales	(55,420)	(85,257)	(113,848)	(281,524)
Assets, Transfers into Level 3	20,165	0	6,490	0
Assets, Transfers out of Level 3	(21,038)	0	(77,629)	0
Assets, Ending Balance	160,046	485,902	160,046	485,902
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	52,214	32,645	53,311	32,994
Assets, Accreted Discounts/Amortized Premiums	556	147	1,928	352
Assets, Realized Gain (Loss)	(91)	3,518	523	4,391
Assets, Change In Net Unrealized Gain/(Loss)	(792)	(1,979)	(2,692)	(464)
Assets, Purchases	4,538	28,400	20,132	66,169
Assets, Sales	(6,591)	(34,684)	(23,368)	(75,395)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	49,834	28,047	49,834	28,047
Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	38,918	44,005	28,309	23,887
Assets, Accreted Discounts/Amortized Premiums	736	521	1,275	1,084
Assets, Realized Gain (Loss)	0	871	0	872
Assets, Change In Net Unrealized Gain/(Loss)	(637)	169	(620)	(291)
Assets, Purchases	26,519	3,980	50,810	24,004
Assets, Sales	(10,226)	(12,131)	(24,464)	(12,141)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	55,310	37,415	55,310	37,415
Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	30,845	23,566	27,482	24,062
Assets, Accreted Discounts/Amortized Premiums	405	0	848	0
Assets, Realized Gain (Loss)	1,422	359	1,664	377
Assets, Change In Net Unrealized Gain/(Loss)	(215)	1,214	(70)	954
Assets, Purchases	3,782	1,695	9,758	1,695
Assets, Sales	(15,310)	(3,463)	(18,753)	(3,717)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	20,929	23,371	20,929	23,371
Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	88,847	47,458	123,338	38,069
Assets, Accreted Discounts/Amortized Premiums	149	(812)	(4,473)	(654)
Assets, Realized Gain (Loss)	(819)	450	(48)	354
Assets, Change In Net Unrealized Gain/(Loss)	252	(492)	(1,453)	56
Assets, Purchases	39,110	40,300	49,587	54,187
Assets, Sales	(29,151)	(5,589)	(68,563)	(10,697)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	98,388	81,315	98,388	81,315
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	34,773		22,950
Assets, Accreted Discounts/Amortized Premiums	(1,701)		(3,419)
Assets, Realized Gain (Loss)	0		0
Assets, Change In Net Unrealized Gain/(Loss)	225		776
Assets, Purchases	25,082		41,139
Assets, Sales	(5,922)		(8,989)
Assets, Transfers into Level 3	0		0
Assets, Transfers out of Level 3	0		0
Assets, Ending Balance	52,457		52,457
Investments [Member] | Corporate Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	31,836		42,708
Assets, Accreted Discounts/Amortized Premiums	16		47
Assets, Realized Gain (Loss)	(78)		108
Assets, Change In Net Unrealized Gain/(Loss)	(1,809)		(2,390)
Assets, Purchases	1,025		12,630
Assets, Sales	(4,712)		(26,825)
Assets, Transfers into Level 3	0		0
Assets, Transfers out of Level 3	0		0
Assets, Ending Balance	26,278		26,278
Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	9,070	97	8,635	0
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	164	(10)	248	(10)
Assets, Change In Net Unrealized Gain/(Loss)	(10)	(13)	527	(17)
Assets, Purchases	2,774	1,658	5,245	1,759
Assets, Sales	(2,496)	(91)	(5,153)	(91)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	9,502	1,641	9,502	1,641
Investments [Member] | Private Corporate Equity Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	21,300		14,512
Assets, Accreted Discounts/Amortized Premiums	0		0
Assets, Realized Gain (Loss)	115		116
Assets, Change In Net Unrealized Gain/(Loss)	268		498
Assets, Purchases	1,116		7,688
Assets, Sales	(450)		(465)
Assets, Transfers into Level 3	0		0
Assets, Transfers out of Level 3	0		0
Assets, Ending Balance	22,349		22,349
Financial Derivatives - Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	11,027	15,174	11,487	16,646
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	(1,278)	(467)	(877)	724
Assets, Change In Net Unrealized Gain/(Loss)	1,186	586	949	(625)
Assets, Purchases	24	417	46	456
Assets, Sales	(1,163)	(1,548)	(1,809)	(3,039)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	9,796	14,162	9,796	14,162
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	10,809	15,174	11,387	16,646
Assets, Accreted Discounts/Amortized Premiums	0	0	0	0
Assets, Realized Gain (Loss)	(1,563)	(467)	(1,162)	724
Assets, Change In Net Unrealized Gain/(Loss)	1,056	586	701	(625)
Assets, Purchases	3	417	25	456
Assets, Sales	(856)	(1,548)	(1,502)	(3,039)
Assets, Transfers into Level 3	0	0	0	0
Assets, Transfers out of Level 3	0	0	0	0
Assets, Ending Balance	9,449	14,162	9,449	14,162
Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	118		0
Assets, Accreted Discounts/Amortized Premiums	0		0
Assets, Realized Gain (Loss)	285		285
Assets, Change In Net Unrealized Gain/(Loss)	130		248
Assets, Purchases	21		21
Assets, Sales	(307)		(307)
Assets, Transfers into Level 3	0		0
Assets, Transfers out of Level 3	0		0
Assets, Ending Balance	247		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
Assets, Accreted Discounts/Amortized Premiums	0		0
Assets, Realized Gain (Loss)	0		0
Assets, Change In Net Unrealized Gain/(Loss)	0		0
Assets, Purchases	0		0
Assets, Sales	0		0
Assets, Transfers into Level 3	0		0
Assets, Transfers out of Level 3	0		0
Assets, Ending Balance	100		100
Financial Derivatives - Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(546)	(350)	(239)	(350)
Liabilities, Accreted Discounts/Amortized Premiums	0	0	0	0
Liabilities, Realized Gain/(Loss)	330	(20)	311	(39)
Liabilities, Change In Net Unrealized Gain/(Loss)	(1,637)	0	(1,944)	0
Liabilities, Purchases	(353)	0	(353)	0
Liabilities, Sales	23	20	42	39
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(2,183)	(350)	(2,183)	(350)
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	(239)	(350)	(239)	(350)
Liabilities, Accreted Discounts/Amortized Premiums	0	0	0	0
Liabilities, Realized Gain/(Loss)	(23)	(20)	(42)	(39)
Liabilities, Change In Net Unrealized Gain/(Loss)	(41)	0	(41)	0
Liabilities, Purchases	0	0	0	0
Liabilities, Sales	23	20	42	39
Liabilities, Transfers into Level 3	0	0	0	0
Liabilities, Transfers out of Level 3	0	0	0	0
Liabilities, Ending Balance	(280)	$ (350)	(280)	$ (350)
Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(307)		0
Liabilities, Accreted Discounts/Amortized Premiums	0		0
Liabilities, Realized Gain/(Loss)	353		353
Liabilities, Change In Net Unrealized Gain/(Loss)	(1,596)		(1,903)
Liabilities, Purchases	(353)		(353)
Liabilities, Sales	0		0
Liabilities, Transfers into Level 3	0		0
Liabilities, Transfers out of Level 3	0		0
Liabilities, Ending Balance	$ (1,903)		$ (1,903)