Valuation (Schedule Of Significant Unobservable Inputs, Qualitative Information) (Details) - Level 3 [Member]		3 Months Ended		12 Months Ended
		Mar. 31, 2017 USD ($)		Dec. 31, 2016 USD ($)
Market Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 41,034,000		$ 47,024,000
Market Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		1.94		2.00
Market Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		115.30		101.02
Market Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		70.74		67.51
Market Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 62,529,000		$ 37,517,000
Market Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		11.00		9.42
Market Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		380.00		100.25
Market Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		106.17		83.36
Market Approach Valuation Technique [Member] | Corporate Debt and non-exchange traded corporate equity [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 57,671,000		$ 19,017,000
Market Approach Valuation Technique [Member] | Corporate Debt and non-exchange traded corporate equity [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		1.59		1.88
Market Approach Valuation Technique [Member] | Corporate Debt and non-exchange traded corporate equity [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		102.46		102.25
Market Approach Valuation Technique [Member] | Corporate Debt and non-exchange traded corporate equity [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		91.97		87.14
Market Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 23,401,000		$ 27,283,000
Market Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		5.40		5.17
Market Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		81.30		77.75
Market Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		40.29		40.88
Market Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 24,890,000		$ 23,322,000
Market Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		1.95		2.47
Market Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		21.31		20.17
Market Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation		11.97		11.65
Income Approach Valuation Technique [Member] | Corporate debt and warrants [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value				$ 10,080,000
Income Approach Valuation Technique [Member] | Corporate debt and warrants [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield				19.70%
Income Approach Valuation Technique [Member] | Corporate debt and warrants [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield				19.70%
Income Approach Valuation Technique [Member] | Corporate debt and warrants [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield				19.70%
Income Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 39,298,000		$ 43,059,000
Income Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		2.30%		0.60%
Projected Collateral Prepayments		0.00%		0.00%
Fair Value Inputs Losses		0.50%		1.40%
Fair Value Inputs Projected Collateral Recoveries		0.00%		0.40%
Fair Value Inputs Projected Collateral Scheduled Amortization		0.00%		0.00%
Income Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		27.30%		20.50%
Projected Collateral Prepayments		84.50%		81.00%
Fair Value Inputs Losses		51.30%		51.20%
Fair Value Inputs Projected Collateral Recoveries		52.40%		53.60%
Fair Value Inputs Projected Collateral Scheduled Amortization		90.40%		90.70%
Income Approach Valuation Technique [Member] | Private Label Residential Mortgage Backed Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		12.40%		11.00%
Projected Collateral Prepayments		7.50%		10.00%
Fair Value Inputs Losses		44.10%		41.40%
Fair Value Inputs Projected Collateral Recoveries		44.20%		41.20%
Fair Value Inputs Projected Collateral Scheduled Amortization		4.20%		7.40%
Total Outstanding Collateral		100.00%		100.00%
Income Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 8,032,000		$ 7,439,000
Income Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		5.00%		11.20%
Projected Collateral Prepayments		2.90%		11.40%
Fair Value Inputs Losses		1.10%		4.50%
Fair Value Inputs Projected Collateral Recoveries		1.50%		1.50%
Fair Value Inputs Projected Collateral Scheduled Amortization		16.60%		29.80%
Income Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		50.80%		50.30%
Projected Collateral Prepayments		67.10%		55.20%
Fair Value Inputs Losses		47.20%		28.30%
Fair Value Inputs Projected Collateral Recoveries		33.20%		27.20%
Fair Value Inputs Projected Collateral Scheduled Amortization		52.70%		51.50%
Income Approach Valuation Technique [Member] | Collateralized Loan Obligations [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		18.10%		20.50%
Projected Collateral Prepayments		42.60%		45.50%
Fair Value Inputs Losses		10.70%		10.70%
Fair Value Inputs Projected Collateral Recoveries		8.20%		8.60%
Fair Value Inputs Projected Collateral Scheduled Amortization		38.50%		35.20%
Total Outstanding Collateral		100.00%		100.00%
Income Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 17,899,000		$ 15,985,000
Income Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		11.60%		8.80%
Fair Value Inputs Losses		0.40%		0.10%
Fair Value Inputs Projected Collateral Recoveries		1.80%		0.90%
Fair Value Inputs Projected Collateral Scheduled Amortization		77.60%		77.80%
Income Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		59.60%		57.00%
Fair Value Inputs Losses		5.30%		5.30%
Fair Value Inputs Projected Collateral Recoveries		17.10%		20.50%
Fair Value Inputs Projected Collateral Scheduled Amortization		97.80%		99.00%
Income Approach Valuation Technique [Member] | Private Label Commercial Mortgage-Backed Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		22.40%		23.60%
Fair Value Inputs Losses		1.60%		2.20%
Fair Value Inputs Projected Collateral Recoveries		6.50%		10.70%
Fair Value Inputs Projected Collateral Scheduled Amortization		91.90%		87.10%
Total Outstanding Collateral		100.00%		100.00%
Income Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 4,535,000		$ 6,300,000
Income Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Projected Collateral Prepayments		9.70%		0.00%
Fair Value Inputs Losses		0.00%		0.00%
Fair Value Inputs Projected Collateral Scheduled Amortization		0.00%		0.00%
LIBOR OAS		3.71%	[1]	1.42%	[2]
Income Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Projected Collateral Prepayments		100.00%		100.00%
Fair Value Inputs Losses		11.30%		15.70%
Fair Value Inputs Projected Collateral Scheduled Amortization		90.30%		88.10%
LIBOR OAS		19.50%	[1]	28.31%	[2]
Income Approach Valuation Technique [Member] | Agency Interest Only Residential Mortgage-Backed Securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Projected Collateral Prepayments		64.00%		62.60%
Fair Value Inputs Losses		1.10%		1.00%
Fair Value Inputs Projected Collateral Scheduled Amortization		34.90%		36.40%
Total Outstanding Collateral		100.00%		100.00%
LIBOR OAS		7.11%	[1]	5.68%	[2]
Income Approach Valuation Technique [Member] | Corporate Debt [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 6,320,000
Income Approach Valuation Technique [Member] | Corporate Debt [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		16.10%
Income Approach Valuation Technique [Member] | Corporate Debt [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		16.10%
Income Approach Valuation Technique [Member] | Corporate Debt [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		16.10%
Income Approach Valuation Technique [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 114,278,000		$ 114,472,000
Income Approach Valuation Technique [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		8.90%		8.50%
Projected Collateral Prepayments		0.00%		0.00%
Fair Value Inputs Losses		0.00%		3.30%
Fair Value Inputs Projected Collateral Scheduled Amortization		0.00%		0.00%
Income Approach Valuation Technique [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		19.00%		25.00%
Projected Collateral Prepayments		48.80%		45.40%
Fair Value Inputs Losses		97.60%		97.40%
Fair Value Inputs Projected Collateral Scheduled Amortization		100.00%		87.70%
Income Approach Valuation Technique [Member] | Consumer loans and asset-backed securities backed by consumer loans [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		10.70%		10.90%
Projected Collateral Prepayments		35.70%		25.60%
Fair Value Inputs Losses		8.50%		9.90%
Fair Value Inputs Projected Collateral Scheduled Amortization		55.80%		64.50%
Total Outstanding Collateral		100.00%		100.00%
Income Approach Valuation Technique [Member] | Performing Commercial Mortgage Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 54,768,000		$ 32,557,000
Income Approach Valuation Technique [Member] | Performing Commercial Mortgage Loans [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		8.00%		8.00%
Income Approach Valuation Technique [Member] | Performing Commercial Mortgage Loans [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		15.40%		17.20%
Income Approach Valuation Technique [Member] | Performing Commercial Mortgage Loans [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		10.80%		11.60%
Income Approach Valuation Technique [Member] | Performing Residential Mortgage Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 104,406,000		$ 78,576,000
Income Approach Valuation Technique [Member] | Performing Residential Mortgage Loans [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		1.70%		5.00%
Income Approach Valuation Technique [Member] | Performing Residential Mortgage Loans [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		17.40%		13.50%
Income Approach Valuation Technique [Member] | Performing Residential Mortgage Loans [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		6.50%		6.60%
Income Approach Valuation Technique [Member] | Non-performing Residential Mortgage Loans and Residential Real Estate Owned [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 9,464,000		$ 7,413,000
Income Approach Valuation Technique [Member] | Non-performing Residential Mortgage Loans and Residential Real Estate Owned [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		2.00%		5.80%
Months to Resolution		4 months 6 days		1 month 24 days
Income Approach Valuation Technique [Member] | Non-performing Residential Mortgage Loans and Residential Real Estate Owned [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		75.60%		39.90%
Months to Resolution		185 months 6 days		162 months 27 days
Income Approach Valuation Technique [Member] | Non-performing Residential Mortgage Loans and Residential Real Estate Owned [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		14.60%		9.70%
Months to Resolution		47 months		41 months 27 days
Income Approach Valuation Technique [Member] | Non-performing Commercial Mortgage Loans and Commercial Real Estate Owned [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 31,910,000		$ 30,222,000
Income Approach Valuation Technique [Member] | Non-performing Commercial Mortgage Loans and Commercial Real Estate Owned [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		7.70%		10.20%
Months to Resolution		3 months		3 months
Income Approach Valuation Technique [Member] | Non-performing Commercial Mortgage Loans and Commercial Real Estate Owned [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		20.00%		27.80%
Months to Resolution		39 months 3 days		39 months 3 days
Income Approach Valuation Technique [Member] | Non-performing Commercial Mortgage Loans and Commercial Real Estate Owned [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		13.70%		16.30%
Months to Resolution		18 months 18 days		19 months 15 days
Credit Default Swaps On Asset Backed Securities [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 5,610,000		$ 5,070,000
Credit Default Swaps On Asset Backed Securities [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Projected Collateral Prepayments		19.50%		19.30%
Fair Value Inputs Losses		15.50%		15.30%
Fair Value Inputs Projected Collateral Recoveries		5.10%		4.70%
Fair Value Inputs Projected Collateral Scheduled Amortization		43.30%		43.20%
Credit Default Swaps On Asset Backed Securities [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Projected Collateral Prepayments		29.60%		29.80%
Fair Value Inputs Losses		28.20%		27.60%
Fair Value Inputs Projected Collateral Recoveries		14.80%		15.30%
Fair Value Inputs Projected Collateral Scheduled Amortization		49.00%		50.20%
Credit Default Swaps On Asset Backed Securities [Member] | Income Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Projected Collateral Prepayments		22.20%		22.70%
Fair Value Inputs Losses		22.80%		22.20%
Fair Value Inputs Projected Collateral Recoveries		9.60%		8.70%
Fair Value Inputs Projected Collateral Scheduled Amortization		45.40%		46.40%
Total Outstanding Collateral		100.00%		100.00%
Total Return Swaps [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure				$ (94,000)
Total Return Swaps [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation	[3]			98.25
Total Return Swaps [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation	[3]			99.50
Total Return Swaps [Member] | Market Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Non Binding Third-Party Valuation	[3]			98.77
Corporate Equity Investments [Member] | Non-exchange traded equity investments in commercial mortgage-related private partnerships [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 3,099,000		$ 3,090,000
Corporate Equity Investments [Member] | Non-exchange traded equity investments in commercial mortgage-related private partnerships [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		16.50%		16.50%
Fair Value Assumptions, Expected Term		1 month 27 days		2 months 27 days
Corporate Equity Investments [Member] | Non-exchange traded equity investments in commercial mortgage-related private partnerships [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		16.50%		16.50%
Fair Value Assumptions, Expected Term		1 month 27 days		2 months 27 days
Corporate Equity Investments [Member] | Non-exchange traded equity investments in commercial mortgage-related private partnerships [Member] | Income Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Yield		16.50%		16.50%
Fair Value Assumptions, Expected Term		1 month 27 days		2 months 27 days
Corporate Equity Investments [Member] | Non-Exchange Traded Preferred and Common Equity Investment in Mortgage-Related Entities [Member] | Enterprise Value [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 2,500,000		$ 2,500,000
Corporate Equity Investments [Member] | Non-Exchange Traded Preferred and Common Equity Investment in Mortgage-Related Entities [Member] | Enterprise Value [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Equity Multiple		1.4	[4]	1.3	[5]
Corporate Equity Investments [Member] | Non-Exchange Traded Preferred and Common Equity Investment in Mortgage-Related Entities [Member] | Enterprise Value [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Equity Multiple		1.4	[4]	1.3	[5]
Corporate Equity Investments [Member] | Non-Exchange Traded Preferred and Common Equity Investment in Mortgage-Related Entities [Member] | Enterprise Value [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Equity Multiple		1.4	[4]	1.3	[5]
Corporate Equity Investments [Member] | Non-Exchange Traded Preferred Equity Investment in Mortgage-Related Entities [Member] | Cash Flows [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value		$ 17,500,000		$ 12,500,000

[1] Shown in basis points.

[2] Shown in basis points.

[3] Represents valuations on underlying assets.

[4] Represent an estimation of where market participants might value an enterprise.

[5] Represent an estimation of where market participants might value an enterprise.