Valuation (Fair Value Measurement Using Significant Unobservable Inputs) (Details) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	$ 493,541	$ 638,486
Assets, Accreted Discounts/Amortized Premiums	(4,040)	(3,573)
Assets, Realized Gain (Loss)	(1,367)	3,976
Assets, Change In Net Unrealized Gain/(Loss)	(6,610)	23
Assets, Purchases	114,160	100,888
Assets, Sales	(72,987)	(146,400)
Assets, Transfers into Level 3	12,070	23,221
Assets, Transfers out of Level 3	(15,120)	(102,085)
Assets, Ending Balance	519,647	514,536
Liabilities, Begining Balance	(6,159)	(1,013)
Liabilities, Accreted Discounts/Amortized Premiums	1	(2)
Liabilities, Realized Gain/(Loss)	(1,907)	(19)
Liabilities, Change In Net Unrealized Gain/(Loss)	3,952	(288)
Liabilities Purchases/Payments	3,224	88
Liabilities, Sales/Issuance	(3,651)	19
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	(4,540)	(1,215)
Change in net unrealized gain (loss) on investments Level 3 Held At End of Period	(7,700)	(3,200)
Change in net unrealized gain (loss) in financial derivative assets Level 3 Held At End of Period	3,600	(200)
Change in net unrealized Gain (Loss) on financial derivative liabilities Level 3 Held At End of Period	600	(300)
Change in net unrealized gain (loss) in securitized debt Level 3 Held At End of Period		19
Change in net unrealized Gain (Loss) On Guarantees Level 3 Held At End Of Period	200
Securitized Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance		(774)
Liabilities, Accreted Discounts/Amortized Premiums		(2)
Liabilities, Realized Gain/(Loss)		0
Liabilities, Change In Net Unrealized Gain/(Loss)		19
Liabilities, Payments		88
Liabilities, Issuances		0
Liabilities, Transfers into Level 3		0
Liabilities, Transfers out of Level 3		0
Liabilities, Ending Balance		(669)
Guarantees [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(828)
Liabilities, Accreted Discounts/Amortized Premiums	0
Liabilities, Realized Gain/(Loss)	0
Liabilities, Change In Net Unrealized Gain/(Loss)	212
Liabilities, Payments	0
Liabilities, Issuances	0
Liabilities, Transfers into Level 3	0
Liabilities, Transfers out of Level 3	0
Liabilities, Ending Balance	(616)
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	486,974	626,999
Assets, Accreted Discounts/Amortized Premiums	(4,040)	(3,573)
Assets, Realized Gain (Loss)	2,107	3,575
Assets, Change In Net Unrealized Gain/(Loss)	(7,494)	260
Assets, Purchases	110,556	100,866
Assets, Sales	(72,807)	(145,754)
Assets, Transfers into Level 3	12,070	23,221
Assets, Transfers out of Level 3	(15,120)	(102,085)
Assets, Ending Balance	512,246	503,509
Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	24,918	31,385
Assets, Accreted Discounts/Amortized Premiums	(2,057)	(2,006)
Assets, Realized Gain (Loss)	(9)	471
Assets, Change In Net Unrealized Gain/(Loss)	(546)	(96)
Assets, Purchases	0	1,190
Assets, Sales	0	(4,609)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	22,306	26,335
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	116,435	274,369
Assets, Accreted Discounts/Amortized Premiums	605	2,388
Assets, Realized Gain (Loss)	313	1,206
Assets, Change In Net Unrealized Gain/(Loss)	(1,709)	3,062
Assets, Purchases	5,731	6,633
Assets, Sales	(4,943)	(39,423)
Assets, Transfers into Level 3	12,070	23,221
Assets, Transfers out of Level 3	(15,120)	(102,085)
Assets, Ending Balance	113,382	169,371
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	34,145	53,311
Assets, Accreted Discounts/Amortized Premiums	455	1,372
Assets, Realized Gain (Loss)	322	614
Assets, Change In Net Unrealized Gain/(Loss)	(3,000)	(1,900)
Assets, Purchases	7,844	15,594
Assets, Sales	(4,416)	(16,777)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	35,350	52,214
Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	66,399	28,309
Assets, Accreted Discounts/Amortized Premiums	546	539
Assets, Realized Gain (Loss)	183	0
Assets, Change In Net Unrealized Gain/(Loss)	893	17
Assets, Purchases	13,424	24,291
Assets, Sales	(25,080)	(14,238)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	56,365	38,918
Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	22,089	27,482
Assets, Accreted Discounts/Amortized Premiums	107	443
Assets, Realized Gain (Loss)	108	242
Assets, Change In Net Unrealized Gain/(Loss)	275	144
Assets, Purchases	14,965	5,976
Assets, Sales	(1,964)	(3,442)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	35,580	30,845
Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	45,974	121,994	[1]
Assets, Accreted Discounts/Amortized Premiums	(927)	(4,626)	[1]
Assets, Realized Gain (Loss)	1,080	772	[1]
Assets, Change In Net Unrealized Gain/(Loss)	272	(1,701)	[1]
Assets, Purchases	0	10,477	[1]
Assets, Sales	(11,984)	(38,086)	[1]
Assets, Transfers into Level 3	0	0	[1]
Assets, Transfers out of Level 3	0	0	[1]
Assets, Ending Balance	34,415	88,830	[1]
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	115,376	24,294	[1]
Assets, Accreted Discounts/Amortized Premiums	(2,882)	(1,714)	[1]
Assets, Realized Gain (Loss)	0	0	[1]
Assets, Change In Net Unrealized Gain/(Loss)	105	547	[1]
Assets, Purchases	51,910	16,057	[1]
Assets, Sales	(20,655)	(4,394)	[1]
Assets, Transfers into Level 3	0	0	[1]
Assets, Transfers out of Level 3	0	0	[1]
Assets, Ending Balance	143,854	34,790	[1]
Investments [Member] | Corporate Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	27,028	42,708
Assets, Accreted Discounts/Amortized Premiums	113	31
Assets, Realized Gain (Loss)	(20)	186
Assets, Change In Net Unrealized Gain/(Loss)	(3,975)	(580)
Assets, Purchases	2,967	11,605
Assets, Sales	(1,561)	(22,114)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	24,552	31,836
Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	12,522	8,635
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	260	84
Assets, Change In Net Unrealized Gain/(Loss)	1,419	537
Assets, Purchases	9,788	2,471
Assets, Sales	(2,146)	(2,657)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	21,843	9,070
Investments [Member] | Private Corporate Equity Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	22,088	14,512
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	(130)	0
Assets, Change In Net Unrealized Gain/(Loss)	(1,228)	230
Assets, Purchases	3,927	6,572
Assets, Sales	(58)	(14)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	24,599	21,300
Financial Derivatives - Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	6,567	11,487
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	(3,474)	401
Assets, Change In Net Unrealized Gain/(Loss)	884	(237)
Assets, Purchases	3,604	22
Assets, Sales	(180)	(646)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	7,401	11,027
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	6,332	11,387
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	91	401
Assets, Change In Net Unrealized Gain/(Loss)	(105)	(355)
Assets, Purchases	36	22
Assets, Sales	(127)	(646)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	6,227	10,809
Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	85	0
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	(3,515)	0
Assets, Change In Net Unrealized Gain/(Loss)	989	118
Assets, Purchases	3,568	0
Assets, Sales	(53)	0
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	1,074	118
Financial Derivatives - Assets [Member] | Warrant [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	150	100
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	(50)	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	(4,883)	(239)
Liabilities, Accreted Discounts/Amortized Premiums	0	0
Liabilities, Realized Gain/(Loss)	(2,267)	(19)
Liabilities, Change In Net Unrealized Gain/(Loss)	3,989	(307)
Liabilities, Purchases	2,337	0
Liabilities, Sales	(71)	19
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	(895)	(546)
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	(221)	(239)
Liabilities, Accreted Discounts/Amortized Premiums	0	0
Liabilities, Realized Gain/(Loss)	(16)	(19)
Liabilities, Change In Net Unrealized Gain/(Loss)	1	0
Liabilities, Purchases	0	0
Liabilities, Sales	16	19
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	(220)	(239)
Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(4,662)	0
Liabilities, Accreted Discounts/Amortized Premiums	0	0
Liabilities, Realized Gain/(Loss)	(2,251)	0
Liabilities, Change In Net Unrealized Gain/(Loss)	3,988	(307)
Liabilities, Purchases	2,337	0
Liabilities, Sales	(87)	0
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	(675)	$ (307)
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	(448)
Liabilities, Accreted Discounts/Amortized Premiums	1
Liabilities, Realized Gain/(Loss)	360
Liabilities, Change In Net Unrealized Gain/(Loss)	(249)
Liabilities, Purchases	887
Liabilities, Sales	(3,580)
Liabilities, Transfers into Level 3	0
Liabilities, Transfers out of Level 3	0
Liabilities, Ending Balance	(3,029)
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	(448)
Liabilities, Accreted Discounts/Amortized Premiums	1
Liabilities, Realized Gain/(Loss)	360
Liabilities, Change In Net Unrealized Gain/(Loss)	(249)
Liabilities, Purchases	887
Liabilities, Sales	(3,580)
Liabilities, Transfers into Level 3	0
Liabilities, Transfers out of Level 3	0
Liabilities, Ending Balance	$ (3,029)

[1] Conformed to prior period presentation.