Valuation (Fair Value Measurement Using Significant Unobservable Inputs) (Details) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	$ 523,837	$ 493,541
Assets, Accreted Discounts/Amortized Premiums	(4,228)	(4,040)
Assets, Realized Gain (Loss)	743	(1,367)
Assets, Change In Net Unrealized Gain/(Loss)	10,387	(6,610)
Assets, Purchases	206,874	114,160
Assets, Sales	(106,310)	(72,987)
Assets, Transfers into Level 3	3,473	12,070
Assets, Transfers out of Level 3	(5,414)	(15,120)
Assets, Ending Balance	629,362	519,647
Liabilities, Begining Balance		(6,159)
Liabilities, Accreted Discounts/Amortized Premiums		1
Liabilities, Realized Gain/(Loss)		(1,907)
Liabilities, Change In Net Unrealized Gain/(Loss)		3,952
Liabilities Purchases/Payments		3,224
Liabilities, Sales/Issuance		(3,651)
Liabilities, Transfers into Level 3		0
Liabilities, Transfers out of Level 3		0
Liabilities, Ending Balance		(4,540)
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	518,250	486,974
Assets, Accreted Discounts/Amortized Premiums	(4,228)	(4,040)
Assets, Realized Gain (Loss)	649	2,107
Assets, Change In Net Unrealized Gain/(Loss)	10,046	(7,494)
Assets, Purchases	206,815	110,556
Assets, Sales	(106,057)	(72,807)
Assets, Transfers into Level 3	3,473	12,070
Assets, Transfers out of Level 3	(5,414)	(15,120)
Assets, Ending Balance	623,534	512,246
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	6,900	(7,700)
Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	29,622	24,918
Assets, Accreted Discounts/Amortized Premiums	(2,592)	(2,057)
Assets, Realized Gain (Loss)	(35)	(9)
Assets, Change In Net Unrealized Gain/(Loss)	228	(546)
Assets, Purchases	2,202	0
Assets, Sales	0	0
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	29,425	22,306
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	90,083	116,435
Assets, Accreted Discounts/Amortized Premiums	1,478	605
Assets, Realized Gain (Loss)	(703)	313
Assets, Change In Net Unrealized Gain/(Loss)	2,893	(1,709)
Assets, Purchases	8,049	5,731
Assets, Sales	(19,527)	(4,943)
Assets, Transfers into Level 3	3,473	12,070
Assets, Transfers out of Level 3	(5,414)	(15,120)
Assets, Ending Balance	80,332	113,382
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	43,268	34,145
Assets, Accreted Discounts/Amortized Premiums	356	455
Assets, Realized Gain (Loss)	342	322
Assets, Change In Net Unrealized Gain/(Loss)	1,411	(3,000)
Assets, Purchases	0	7,844
Assets, Sales	(4,077)	(4,416)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	41,300	35,350
Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	61,129	66,399
Assets, Accreted Discounts/Amortized Premiums	530	546
Assets, Realized Gain (Loss)	337	183
Assets, Change In Net Unrealized Gain/(Loss)	1,206	893
Assets, Purchases	23,045	13,424
Assets, Sales	(23,739)	(25,080)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	62,508	56,365
Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	84,290	22,089
Assets, Accreted Discounts/Amortized Premiums	140	107
Assets, Realized Gain (Loss)	(51)	108
Assets, Change In Net Unrealized Gain/(Loss)	404	275
Assets, Purchases	34,138	14,965
Assets, Sales	(6,271)	(1,964)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	112,650	35,580
Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	44,956	45,974
Assets, Accreted Discounts/Amortized Premiums	(1,183)	(927)
Assets, Realized Gain (Loss)	920	1,080
Assets, Change In Net Unrealized Gain/(Loss)	2,532	272
Assets, Purchases	38,712	0
Assets, Sales	(15,376)	(11,984)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	70,561	34,415
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	114,472	115,376
Assets, Accreted Discounts/Amortized Premiums	(3,057)	(2,882)
Assets, Realized Gain (Loss)	(552)	0
Assets, Change In Net Unrealized Gain/(Loss)	646	105
Assets, Purchases	24,418	51,910
Assets, Sales	(21,649)	(20,655)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	114,278	143,854
Investments [Member] | Corporate Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	25,004	27,028
Assets, Accreted Discounts/Amortized Premiums	100	113
Assets, Realized Gain (Loss)	331	(20)
Assets, Change In Net Unrealized Gain/(Loss)	158	(3,975)
Assets, Purchases	47,094	2,967
Assets, Sales	(13,078)	(1,561)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	59,609	24,552
Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	3,349	12,522
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	60	260
Assets, Change In Net Unrealized Gain/(Loss)	106	1,419
Assets, Purchases	24,157	9,788
Assets, Sales	(2,282)	(2,146)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	25,390	21,843
Investments [Member] | Corporate Equity Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	22,077	22,088
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	0	(130)
Assets, Change In Net Unrealized Gain/(Loss)	462	(1,228)
Assets, Purchases	5,000	3,927
Assets, Sales	(58)	(58)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	27,481	24,599
Investments 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)
Investments Sold Short [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)
Financial Derivatives - Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	5,587	6,567
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	94	(3,474)
Assets, Change In Net Unrealized Gain/(Loss)	341	884
Assets, Purchases	59	3,604
Assets, Sales	(253)	(180)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	5,828	7,401
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	500	3,600
Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	155	85
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	157	(3,515)
Assets, Change In Net Unrealized Gain/(Loss)	(155)	989
Assets, Purchases	0	3,568
Assets, Sales	(157)	(53)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	0	1,074
Financial Derivatives - Assets [Member] | Warrant [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	106	150
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	(100)	(50)
Assets, Change In Net Unrealized Gain/(Loss)	(6)	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	0	100
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	5,326	6,332
Assets, Accreted Discounts/Amortized Premiums	0	0
Assets, Realized Gain (Loss)	37	91
Assets, Change In Net Unrealized Gain/(Loss)	502	(105)
Assets, Purchases	59	36
Assets, Sales	(96)	(127)
Assets, Transfers into Level 3	0	0
Assets, Transfers out of Level 3	0	0
Assets, Ending Balance	5,828	6,227
Financial Derivatives - Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(505)	(4,883)
Liabilities, Accreted Discounts/Amortized Premiums	0	0
Liabilities, Realized Gain/(Loss)	(652)	(2,267)
Liabilities, Change In Net Unrealized Gain/(Loss)	714	3,989
Liabilities, Purchases	301	2,337
Liabilities, Sales	(76)	(71)
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	(218)	(895)
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	500	600
Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(249)	(4,662)
Liabilities, Accreted Discounts/Amortized Premiums	0	0
Liabilities, Realized Gain/(Loss)	(206)	(2,251)
Liabilities, Change In Net Unrealized Gain/(Loss)	248	3,988
Liabilities, Purchases	283	2,337
Liabilities, Sales	(76)	(87)
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	0	(675)
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	(256)	(221)
Liabilities, Accreted Discounts/Amortized Premiums	0	0
Liabilities, Realized Gain/(Loss)	(446)	(16)
Liabilities, Change In Net Unrealized Gain/(Loss)	466	1
Liabilities, Purchases	18	0
Liabilities, Sales	0	16
Liabilities, Transfers into Level 3	0	0
Liabilities, Transfers out of Level 3	0	0
Liabilities, Ending Balance	$ (218)	(220)
Guarantees [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)		$ 200