Valuation (Fair Value Measurement Using Significant Unobservable Inputs) (Details) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	$ 629,362		$ 519,647	$ 523,837		$ 493,541
Assets, Accreted Discounts/Amortized Premiums	(9,785)		(4,295)	(13,979)		(8,533)
Assets, Realized Gain (Loss)	2,115		6,250	2,858		4,578
Assets, Change In Net Unrealized Gain/(Loss)	5,455		(3,188)	15,656		(9,151)
Assets, Purchases	156,110		106,972	353,763		221,133
Assets, Sales	(169,558)		(110,295)	(275,956)		(184,698)
Assets, Transfers into Level 3	16,089		12,823	11,348		11,261
Assets, Transfers out of Level 3	(92,443)		(8,790)	(80,182)		(9,007)
Assets, Ending Balance	537,345		519,124	537,345		519,124
Liabilities, Begining Balance			(4,540)			(6,159)
Liabilities, Accreted Discounts/Amortized Premiums			(9)			(8)
Liabilities, Realized Gain/(Loss)			(2,007)			(3,913)
Liabilities, Change In Net Unrealized Gain/(Loss)			(323)			3,628
Liabilities Purchases/Payments			12,716			15,941
Liabilities, Sales/Issuance			(17,346)			(20,998)
Liabilities, Transfers into Level 3			0			0
Liabilities, Transfers out of Level 3			0			0
Liabilities, Ending Balance			(11,509)			(11,509)
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)
Unrealized Gain Loss On Guarantees Level 3 Held At End Of Period			300			500
Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	623,534		512,246	518,250		486,974
Assets, Accreted Discounts/Amortized Premiums	(9,785)		(4,295)	(13,979)		(8,533)
Assets, Realized Gain (Loss)	1,719		2,465	2,368		4,267
Assets, Change In Net Unrealized Gain/(Loss)	6,176		(2,789)	16,035		(9,635)
Assets, Purchases	156,100		110,142	353,695		220,698
Assets, Sales	(169,152)		(109,670)	(275,297)		(183,893)
Assets, Transfers into Level 3	16,089		12,823	11,348		11,261
Assets, Transfers out of Level 3	(92,443)		(8,790)	(80,182)		(9,007)
Assets, Ending Balance	532,238		512,132	532,238		512,132
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	5,100		(2,200)	9,000		(10,900)
Investments [Member] | Agency residential mortgage-backed securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	29,425		22,306	29,622		24,918
Assets, Accreted Discounts/Amortized Premiums	(2,320)		(1,888)	(4,913)		(3,945)
Assets, Realized Gain (Loss)	(402)		(82)	(437)		(90)
Assets, Change In Net Unrealized Gain/(Loss)	(163)		(133)	65		(679)
Assets, Purchases	(417)		303	1,785		302
Assets, Sales	(126)		0	(125)		0
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	(21,101)		0	(21,101)		0
Assets, Ending Balance	4,896		20,506	4,896		20,506
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	80,332		113,382	90,083		116,435
Assets, Accreted Discounts/Amortized Premiums	(476)		1,109	1,036		1,517
Assets, Realized Gain (Loss)	1,137		(290)	434		(283)
Assets, Change In Net Unrealized Gain/(Loss)	3,327		(1,310)	6,034		(2,370)
Assets, Purchases	27,972		1,687	26,800		7,419
Assets, Sales	(9,733)		(6,100)	(29,349)		(12,461)
Assets, Transfers into Level 3	16,089		12,823	11,348		11,261
Assets, Transfers out of Level 3	(39,525)		(8,790)	(27,263)		(9,007)
Assets, Ending Balance	79,123		112,511	79,123		112,511
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	41,300		35,350	43,268		34,145
Assets, Accreted Discounts/Amortized Premiums	276		431	632		886
Assets, Realized Gain (Loss)	(3,338)		0	(2,996)		322
Assets, Change In Net Unrealized Gain/(Loss)	4,991		(839)	6,402		(3,840)
Assets, Purchases	20		0	20		7,844
Assets, Sales	(16,734)		0	(20,811)		(4,415)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	(12,706)		0	(12,706)		0
Assets, Ending Balance	13,809		34,942	13,809		34,942
Investments [Member] | Commercial Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	62,508		56,365	61,129		66,399
Assets, Accreted Discounts/Amortized Premiums	101		727	631		1,272
Assets, Realized Gain (Loss)	79		(1)	416		182
Assets, Change In Net Unrealized Gain/(Loss)	(56)		(671)	1,150		223
Assets, Purchases	4,500		0	27,545		13,424
Assets, Sales	(1,236)		(6,954)	(24,975)		(32,034)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	65,896		49,466	65,896		49,466
Investments [Member] | Residential Mortgage Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	112,650		35,580	84,290		22,089
Assets, Accreted Discounts/Amortized Premiums	537		141	678		248
Assets, Realized Gain (Loss)	1,133		757	1,081		865
Assets, Change In Net Unrealized Gain/(Loss)	(481)		(147)	(77)		127
Assets, Purchases	37,048		17,101	71,186		32,066
Assets, Sales	(14,790)		(6,783)	(21,061)		(8,746)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	136,097		46,649	136,097		46,649
Investments [Member] | Collateralized Loan Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	70,561		34,415	44,956		45,974
Assets, Accreted Discounts/Amortized Premiums	(4,849)		(1,942)	(6,032)		(2,869)
Assets, Realized Gain (Loss)	532		(279)	1,453		801
Assets, Change In Net Unrealized Gain/(Loss)	479		145	3,011		417
Assets, Purchases	18,157		1,178	56,869		1,178
Assets, Sales	(23,233)		(408)	(38,609)		(12,392)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	(19,111)		0	(19,112)		0
Assets, Ending Balance	42,536		33,109	42,536		33,109
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	107,842	[1]	143,854	107,157	[2]	115,376
Assets, Accreted Discounts/Amortized Premiums	(3,208)	[1]	(2,713)	(6,264)	[2]	(5,596)
Assets, Realized Gain (Loss)	478	[1]	6	(74)	[2]	6
Assets, Change In Net Unrealized Gain/(Loss)	(555)	[1]	(655)	281	[2]	(549)
Assets, Purchases	25,594	[1]	37,046	50,012	[2]	88,956
Assets, Sales	(21,480)	[1]	(23,143)	(42,441)	[2]	(43,798)
Assets, Transfers into Level 3	0	[1]	0	0	[2]	0
Assets, Transfers out of Level 3	0	[1]	0	0	[2]	0
Assets, Ending Balance	108,671	[1],[2]	154,395	108,671	[1],[2]	154,395
Investments [Member] | Corporate Debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	59,609		24,552	25,004		27,028
Assets, Accreted Discounts/Amortized Premiums	154		(160)	253		(46)
Assets, Realized Gain (Loss)	216		275	548		255
Assets, Change In Net Unrealized Gain/(Loss)	29		1,874	187		(2,102)
Assets, Purchases	36,397		49,353	83,492		52,320
Assets, Sales	(75,870)		(38,920)	(88,949)		(40,481)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	20,535		36,974	20,535		36,974
Investments [Member] | Real Estate Owned [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	25,390		21,843	3,349		12,522
Assets, Accreted Discounts/Amortized Premiums	0		0	0		0
Assets, Realized Gain (Loss)	365		1,978	424		2,238
Assets, Change In Net Unrealized Gain/(Loss)	(401)		(1,750)	(295)		(331)
Assets, Purchases	54		884	24,211		10,672
Assets, Sales	(431)		(18,793)	(2,712)		(20,939)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	24,977		4,162	24,977		4,162
Investments [Member] | Corporate Equity Investments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	33,917	[1]	24,599	29,392	[2]	22,088
Assets, Accreted Discounts/Amortized Premiums	0	[1]	0	0	[2]	0
Assets, Realized Gain (Loss)	1,519	[1]	101	1,519	[2]	(29)
Assets, Change In Net Unrealized Gain/(Loss)	(994)	[1]	697	(723)	[2]	(531)
Assets, Purchases	6,775	[1]	2,590	11,775	[2]	6,517
Assets, Sales	(5,519)	[1]	(8,569)	(6,265)	[2]	(8,627)
Assets, Transfers into Level 3	0	[1]	0	0	[2]	0
Assets, Transfers out of Level 3	0	[1]	0	0	[2]	0
Assets, Ending Balance	35,698	[1],[2]	19,418	35,698	[1],[2]	19,418
Investments 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)
Unrealized Gain (Loss) On Investments Sold Short, Level 3, Held At End Of Period			(30)			(40)
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			(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)
Financial Derivatives - Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	5,828		7,401	5,587		6,567
Assets, Accreted Discounts/Amortized Premiums	0		0	0		0
Assets, Realized Gain (Loss)	396		3,785	490		311
Assets, Change In Net Unrealized Gain/(Loss)	(721)		(399)	(379)		484
Assets, Purchases	10		(3,170)	68		435
Assets, Sales	(406)		(625)	(659)		(805)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	5,107		6,992	5,107		6,992
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(700)		300	(200)		900
Financial Derivatives - Assets [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance	0		1,074	155		85
Assets, Accreted Discounts/Amortized Premiums	0		0	0		0
Assets, Realized Gain (Loss)	65		3,412	222		(103)
Assets, Change In Net Unrealized Gain/(Loss)	0		(250)	(155)		739
Assets, Purchases	0		(3,146)	0		423
Assets, Sales	(65)		(266)	(222)		(320)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	0		824	0		824
Financial Derivatives - Assets [Member] | Warrant [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Assets, Beginning Balance			100	106		150
Assets, Accreted Discounts/Amortized Premiums			0	0		0
Assets, Realized Gain (Loss)			0	(100)		(50)
Assets, Change In Net Unrealized Gain/(Loss)			0	(6)		0
Assets, Purchases			0	0		0
Assets, Sales			0	0		0
Assets, Transfers into Level 3			0	0		0
Assets, Transfers out of Level 3			0	0		0
Assets, Ending Balance	0		100	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	5,828		6,227	5,326		6,332
Assets, Accreted Discounts/Amortized Premiums	0		0	0		0
Assets, Realized Gain (Loss)	331		373	368		464
Assets, Change In Net Unrealized Gain/(Loss)	(721)		(149)	(218)		(255)
Assets, Purchases	10		(24)	68		12
Assets, Sales	(341)		(359)	(437)		(485)
Assets, Transfers into Level 3	0		0	0		0
Assets, Transfers out of Level 3	0		0	0		0
Assets, Ending Balance	5,107		6,068	5,107		6,068
Financial Derivatives - Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	(218)		(895)	(505)		(4,883)
Liabilities, Accreted Discounts/Amortized Premiums	0		0	0		0
Liabilities, Realized Gain/(Loss)	(104)		(2,178)	(757)		(4,444)
Liabilities, Change In Net Unrealized Gain/(Loss)	12		(318)	727		3,670
Liabilities, Purchases	467		2,348	769		4,686
Liabilities, Sales	(364)		(207)	(441)		(279)
Liabilities, Transfers into Level 3	0		0	0		0
Liabilities, Transfers out of Level 3	0		0	0		0
Liabilities, Ending Balance	(207)		(1,250)	(207)		(1,250)
Fair Value, Liabilities Measured on Recurring Basis, Change in Unrealized Gain (Loss)	10		(600)	50		(100)
Financial Derivatives - Liabilities [Member] | Total Return Swaps [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Liabilities, Begining Balance	0		(675)	(249)		(4,662)
Liabilities, Accreted Discounts/Amortized Premiums	0		0	0		0
Liabilities, Realized Gain/(Loss)	(85)		(2,115)	(292)		(4,365)
Liabilities, Change In Net Unrealized Gain/(Loss)	0		(342)	250		3,646
Liabilities, Purchases	21		2,348	304		4,686
Liabilities, Sales	64		(232)	(13)		(321)
Liabilities, Transfers into Level 3	0		0	0		0
Liabilities, Transfers out of Level 3	0		0	0		0
Liabilities, Ending Balance	0		(1,016)	0		(1,016)
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	(218)		(220)	(256)		(221)
Liabilities, Accreted Discounts/Amortized Premiums	0		0	0		0
Liabilities, Realized Gain/(Loss)	(19)		(63)	(465)		(79)
Liabilities, Change In Net Unrealized Gain/(Loss)	12		24	477		24
Liabilities, Purchases	446		0	465		0
Liabilities, Sales	(428)		25	(428)		42
Liabilities, Transfers into Level 3	0		0	0		0
Liabilities, Transfers out of Level 3	0		0	0		0
Liabilities, Ending Balance	$ (207)		$ (234)	$ (207)		$ (234)

[1] Conformed to current period presentation.

[2] Conformed to current period presentation.