Valuation (Fair Value Measurement Using Significant Unobservable Inputs) (Details) - Level 3 [Member] - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		$ 535,274		$ 708,093	$ 638,486	$ 756,934
Assets, Accreted Discounts/Amortized Premiums		(4,911)		1,646	(7,811)	8,683
Assets, Realized Gain (Loss)		8,908		3,577	23,829	41,633
Assets, Change In Net Unrealized Gain/(Loss)		(13,353)		(3,072)	(22,719)	(12,772)
Assets, Purchases		88,369		178,574	347,139	483,619
Assets, Sales		(117,751)		(117,770)	(439,308)	(507,049)
Assets, Transfers into Level 3		20,154		0	9,667	0
Assets, Transfers out of Level 3		(14,294)		0	(46,887)	0
Assets, Ending Balance		502,396		771,048	502,396	771,048
Liabilities, Begining Balance		(2,851)		(1,275)	(1,013)	(1,333)
Liabilities, Accreted Discounts/Amortized Premiums		(3)		(1)	(5)	(14)
Liabilities, Realized Gain/(Loss)		836		(20)	1,147	(59)
Liabilities, Change In Net Unrealized Gain/(Loss)		(2,349)		(30)	(4,285)	(45)
Liabilities Purchases/Payments		(715)		58	(968)	144
Liabilities, Sales/Issuance		33		20	75	59
Liabilities, Transfers into Level 3		0		0	0	0
Liabilities, Transfers out of Level 3		0		0	0	0
Liabilities, Ending Balance		(5,049)		(1,248)	(5,049)	(1,248)
Change in net unrealized gain (loss) on investments		(11,800)		(2,900)	(21,800)	2,300
Change in net unrealized gain (loss) in financial derivative assets		(300)		(700)	(71)	(1,900)
Change in net unrealized Gain (Loss) on financial derivative liabilities		(1,300)		(29)	(3,000)	(28)
Change in net unrealized gain (loss) in securitized debt		1		(2)	21	(17)
Unrealized Gain Loss On Guarantees Level 3 Held At End Of Period		(1,200)			(1,200)
Securitized Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance		(655)		(925)	(774)	(983)
Liabilities, Accreted Discounts/Amortized Premiums		(3)		(1)	(5)	(14)
Liabilities, Realized Gain/(Loss)		0		0	0	0
Liabilities, Change In Net Unrealized Gain/(Loss)		1		(2)	21	(17)
Liabilities, Payments		154		58	255	144
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		(503)		(870)	(503)	(870)
Guarantees [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance		(13)	[1]		0
Liabilities, Accreted Discounts/Amortized Premiums		0	[1]		0
Liabilities, Realized Gain/(Loss)		0	[1]		0
Liabilities, Change In Net Unrealized Gain/(Loss)		(1,216)	[1]		(1,229)
Liabilities, Payments		0	[1]		0
Liabilities, Issuances		0	[1]		0
Liabilities, Transfers into Level 3		0	[1]		0
Liabilities, Transfers out of Level 3		0	[1]		0
Liabilities, Ending Balance	[1]	(1,229)			(1,229)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		525,478		693,931	626,999	740,288
Assets, Accreted Discounts/Amortized Premiums		(4,911)		1,646	(7,811)	8,683
Assets, Realized Gain (Loss)		8,411		6,437	24,210	43,768
Assets, Change In Net Unrealized Gain/(Loss)		(12,972)		(6,076)	(23,287)	(15,151)
Assets, Purchases		88,341		178,499	347,065	483,089
Assets, Sales		(117,014)		(116,177)	(436,763)	(502,417)
Assets, Transfers into Level 3		20,154		0	9,667	0
Assets, Transfers out of Level 3		(14,294)		0	(46,887)	0
Assets, Ending Balance		493,193		758,260	493,193	758,260
Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		30,385		36,240	31,385	40,504
Assets, Accreted Discounts/Amortized Premiums		(2,249)		(2,188)	(6,196)	(6,523)
Assets, Realized Gain (Loss)		0		286	472	457
Assets, Change In Net Unrealized Gain/(Loss)		(1,135)		492	373	515
Assets, Purchases		1,354		4,695	8,860	7,249
Assets, Sales		0		(953)	(6,539)	(3,630)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		28,355		38,572	28,355	38,572
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		160,046		485,902	274,369	580,772
Assets, Accreted Discounts/Amortized Premiums		2,682		4,770	7,524	15,359
Assets, Realized Gain (Loss)		4,139		3,684	16,855	34,862
Assets, Change In Net Unrealized Gain/(Loss)		(5,191)		(5,030)	(11,589)	(14,366)
Assets, Purchases		10,138		79,431	64,366	233,654
Assets, Sales		(27,217)		(66,687)	(163,848)	(348,211)
Assets, Transfers into Level 3		20,154		0	9,667	0
Assets, Transfers out of Level 3		(14,294)		0	(46,887)	0
Assets, Ending Balance		150,457		502,070	150,457	502,070
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		49,834		28,047	53,311	32,994
Assets, Accreted Discounts/Amortized Premiums		579		145	2,507	497
Assets, Realized Gain (Loss)		25		1,089	549	5,479
Assets, Change In Net Unrealized Gain/(Loss)		(151)		(378)	(2,844)	(842)
Assets, Purchases		1,250		29,496	21,382	95,665
Assets, Sales		(9,022)		(12,082)	(32,390)	(87,476)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		42,515		46,317	42,515	46,317
Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		55,310		37,415	28,309	23,887
Assets, Accreted Discounts/Amortized Premiums		(2)		832	1,273	1,916
Assets, Realized Gain (Loss)		543		1,029	542	1,901
Assets, Change In Net Unrealized Gain/(Loss)		(192)		(382)	(812)	(673)
Assets, Purchases		4,305		8,113	55,115	32,117
Assets, Sales		(5,344)		(17,155)	(29,807)	(29,296)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		54,620		29,852	54,620	29,852
Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		20,929		23,371	27,482	24,062
Assets, Accreted Discounts/Amortized Premiums		279		878	1,127	878
Assets, Realized Gain (Loss)		714		501	2,378	878
Assets, Change In Net Unrealized Gain/(Loss)		(9)		(131)	(80)	823
Assets, Purchases		3,902		(547)	13,660	1,148
Assets, Sales		(8,156)		(6,925)	(26,908)	(10,642)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		17,659		17,147	17,659	17,147
Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		98,388		81,315	123,338	38,069
Assets, Accreted Discounts/Amortized Premiums		(4,862)		(2,791)	(9,335)	(3,444)
Assets, Realized Gain (Loss)		2,581		(170)	2,533	184
Assets, Change In Net Unrealized Gain/(Loss)		(2,678)		(637)	(4,131)	(581)
Assets, Purchases		5,946		43,353	55,533	97,539
Assets, Sales		(42,572)		(11,918)	(111,135)	(22,615)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		56,803		109,152	56,803	109,152
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		52,457			22,950
Assets, Accreted Discounts/Amortized Premiums		(1,413)			(4,832)
Assets, Realized Gain (Loss)		0			0
Assets, Change In Net Unrealized Gain/(Loss)		180			956
Assets, Purchases		43,830			84,969
Assets, Sales		(17,353)			(26,342)
Assets, Transfers into Level 3		0			0
Assets, Transfers out of Level 3		0			0
Assets, Ending Balance		77,701			77,701
Investments [Member] | Corporate Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		26,278			42,708
Assets, Accreted Discounts/Amortized Premiums		75			121
Assets, Realized Gain (Loss)		(28)			80
Assets, Change In Net Unrealized Gain/(Loss)		(3,212)			(5,601)
Assets, Purchases		9,609			22,239
Assets, Sales		(4,475)			(31,300)
Assets, Transfers into Level 3		0			0
Assets, Transfers out of Level 3		0			0
Assets, Ending Balance		28,247			28,247
Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		9,502		1,641	8,635	0
Assets, Accreted Discounts/Amortized Premiums		0		0	0	0
Assets, Realized Gain (Loss)		437		18	685	7
Assets, Change In Net Unrealized Gain/(Loss)		(299)		229	228	212
Assets, Purchases		8,007		6,033	13,252	7,792
Assets, Sales		(2,817)		(457)	(7,970)	(547)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		14,830		7,464	14,830	7,464
Investments [Member] | Private Corporate Equity Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		22,349		0	14,512	0
Assets, Accreted Discounts/Amortized Premiums		0		0	0	0
Assets, Realized Gain (Loss)		0		0	116	0
Assets, Change In Net Unrealized Gain/(Loss)		(285)		(239)	213	(239)
Assets, Purchases		0		7,925	7,689	7,925
Assets, Sales		(58)		0	(524)	0
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		22,006		7,686	22,006	7,686
Financial Derivatives - Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		9,796		14,162	11,487	16,646
Assets, Accreted Discounts/Amortized Premiums		0		0	0	0
Assets, Realized Gain (Loss)		497		(2,860)	(381)	(2,135)
Assets, Change In Net Unrealized Gain/(Loss)		(381)		3,004	568	2,379
Assets, Purchases		28		75	74	530
Assets, Sales		(737)		(1,593)	(2,545)	(4,632)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		9,203		12,788	9,203	12,788
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		9,449		14,162	11,387	16,646
Assets, Accreted Discounts/Amortized Premiums		0		0	0	0
Assets, Realized Gain (Loss)		446		(2,860)	(717)	(2,135)
Assets, Change In Net Unrealized Gain/(Loss)		(310)		3,004	392	2,379
Assets, Purchases		10		75	35	530
Assets, Sales		(668)		(1,593)	(2,170)	(4,632)
Assets, Transfers into Level 3		0		0	0	0
Assets, Transfers out of Level 3		0		0	0	0
Assets, Ending Balance		8,927		12,788	8,927	12,788
Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance		247			0
Assets, Accreted Discounts/Amortized Premiums		0			0
Assets, Realized Gain (Loss)		51			336
Assets, Change In Net Unrealized Gain/(Loss)		(71)			176
Assets, Purchases		18			39
Assets, Sales		(69)			(375)
Assets, Transfers into Level 3		0			0
Assets, Transfers out of Level 3		0			0
Assets, Ending Balance		176			176
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		(2,183)		(350)	(239)	(350)
Liabilities, Accreted Discounts/Amortized Premiums		0		0	0	0
Liabilities, Realized Gain/(Loss)		836		(20)	1,147	(59)
Liabilities, Change In Net Unrealized Gain/(Loss)		(1,134)		(28)	(3,077)	(28)
Liabilities, Purchases		(869)		0	(1,223)	0
Liabilities, Sales		33		20	75	59
Liabilities, Transfers into Level 3		0		0	0	0
Liabilities, Transfers out of Level 3		0		0	0	0
Liabilities, Ending Balance		(3,317)		(378)	(3,317)	(378)
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		(280)		(350)	(239)	(350)
Liabilities, Accreted Discounts/Amortized Premiums		0		0	0	0
Liabilities, Realized Gain/(Loss)		(18)		(20)	(60)	(59)
Liabilities, Change In Net Unrealized Gain/(Loss)		18		(28)	(23)	(28)
Liabilities, Purchases		0		0	0	0
Liabilities, Sales		18		20	60	59
Liabilities, Transfers into Level 3		0		0	0	0
Liabilities, Transfers out of Level 3		0		0	0	0
Liabilities, Ending Balance		(262)		$ (378)	(262)	$ (378)
Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance		(1,903)			0
Liabilities, Accreted Discounts/Amortized Premiums		0			0
Liabilities, Realized Gain/(Loss)		854			1,207
Liabilities, Change In Net Unrealized Gain/(Loss)		(1,152)			(3,054)
Liabilities, Purchases		(869)			(1,223)
Liabilities, Sales		15			15
Liabilities, Transfers into Level 3		0			0
Liabilities, Transfers out of Level 3		0			0
Liabilities, Ending Balance		$ (3,055)			$ (3,055)

[1] Conformed to current period presentation.