Available for Sale Securities (Details) $ in Thousands		12 Months Ended					84 Months Ended
		Dec. 31, 2015 USD ($)		Dec. 31, 2014 USD ($)		Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 9,004,624		$ 8,881,990			$ 9,004,624
Available-for-sale Securities, Fair Value		9,042,733		8,978,945			9,042,733
Available-for-sale Securities, Gross Unrealized Gain		79,970	[1]	129,876	[2]		79,970	[1]
Available-for-sale Securities, Gross Unrealized Loss		(41,034)	[1]	(32,257)	[2]		(41,034)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ (827)	[3]	(664)	[4]		$ (827)	[3]
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.91%					1.91%
Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract]
Available-for-sale Securities, Proceeds		$ 1,600,380		2,664,740		$ 2,436,093
Available-for-sale Securities, Gross realized gains		15,849		24,923		25,711
Available-for-sale Securities, Gross realized losses		(3,791)		(23,384)		(14,991)
Available-for-sale Securites, Related federal and state income tax expense		4,691		599		4,170
Available-for-sale Securities, Pledged as Collateral [Abstract]
Available-for-sale Securities, Pledged As Collateral, Amortized cost		6,831,743		5,855,220			$ 6,831,743
Available-for-sale Securities, Pledged As Collateral, Fair value		$ 6,849,524		$ 5,893,972			$ 6,849,524
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		419		255			419
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 3,873,809		$ 577,473			$ 3,873,809
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		716,700		2,160,051			716,700
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		4,590,509		2,737,524			4,590,509
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		28,496		1,446			28,496
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		13,365		31,475			13,365
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		41,861		32,921			41,861
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	8,781,140					8,781,140
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	8,805,142					8,805,142
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		38,202					38,202
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		39,132					39,132
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		16,318					16,318
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		16,777					16,777
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		138,876					138,876
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		151,361					151,361
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		30,088					30,088
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		30,321					30,321
Fixed maturity securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		9,733					9,733
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		845,594					845,594
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		1,759,651					1,759,651
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		366,147					366,147
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		2,981,125					2,981,125
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		9,779					9,779
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		841,984					841,984
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,752,235					1,752,235
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		363,761					363,761
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 2,967,759					$ 2,967,759
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		3.35%					3.35%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		1.65%					1.65%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		2.08%					2.08%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		1.28%					1.28%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.86%					1.86%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[6]	7.44					7.44
U.S. Treasury securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 1,000		1,005			$ 1,000
Available-for-sale Securities, Fair Value		995		1,005			995
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	0	[2]		0	[1]
Available-for-sale Securities, Gross Unrealized Loss		(5)	[1]	0	[2]		(5)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		0	[3]	0	[4]		0	[3]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		1,000					1,000
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		1,000					1,000
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		995					995
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 995					$ 995
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		0.87%					0.87%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, Nominal Yield		0.87%					0.87%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[6]	2.04					2.04
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		1					1
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 995					$ 995
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0					0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		995					995
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		5					5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0					0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		5					5
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	1,000					1,000
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	995					995
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
Municipal and other tax-exempt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		56,681		63,018			56,681
Available-for-sale Securities, Fair Value		56,817		63,557			56,817
Available-for-sale Securities, Gross Unrealized Gain		873	[1]	1,280	[2]		873	[1]
Available-for-sale Securities, Gross Unrealized Loss		(737)	[1]	(741)	[2]		(737)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]		0	[3]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		9,733					9,733
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		22,433					22,433
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		2,776					2,776
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		21,739					21,739
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		56,681					56,681
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		9,779					9,779
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		22,982					22,982
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		2,832					2,832
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		21,224					21,224
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 56,817					$ 56,817
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	[7]	3.35%					3.35%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	[7]	4.38%					4.38%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield	[7]	3.67%					3.67%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield	[7],[8]	2.01%					2.01%
Available-for-sale Securities, Debt Maturities, Nominal Yield	[7]	3.26%					3.26%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[6]	8.03					8.03
Available-for-sale Securities, Debt Maturities, Effective tax rate for nominal yield calculation		39.00%					39.00%
Available-for-sale Securities, Debt Maturities, Number of days for interest rates to reset		35 days
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		20		22			20
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 9,909		$ 10,838			$ 9,909
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		11,664		12,176			11,664
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		21,573		23,014			21,573
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		27		12			27
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		710		729			710
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		737		741			737
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		33,798					33,798
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		34,503					34,503
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		9,912					9,912
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		9,348					9,348
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		12,971					12,971
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		12,966					12,966
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Credit Losses Recognized [Abstract]
Available-for-sale Securities, Other than Temporary Impairment Losses, Credit Losses Recognized						(1,400)
Commercial mortgage-backed securities guaranteed by U.S. government agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		2,919,044		2,064,091			2,919,044
Available-for-sale Securities, Fair Value		2,905,796		2,048,609			2,905,796
Available-for-sale Securities, Gross Unrealized Gain		5,396	[1]	4,437	[2]		5,396	[1]
Available-for-sale Securities, Gross Unrealized Loss		(18,644)	[1]	(19,919)	[2]		(18,644)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]		0	[3]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		822,161					822,161
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		1,756,875					1,756,875
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		340,008					340,008
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		2,919,044					2,919,044
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		818,007					818,007
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		1,749,403					1,749,403
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		338,386					338,386
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 2,905,796					$ 2,905,796
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		1.57%					1.57%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		2.08%					2.08%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		1.23%					1.23%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.84%					1.84%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[6]	7.39					7.39
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		213		104			213
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 1,582,469		$ 223,106			$ 1,582,469
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		484,258		1,238,376			484,258
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,066,727		1,461,482			2,066,727
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		11,419		454			11,419
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		7,225		19,465			7,225
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		18,644		19,919			18,644
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	2,919,044					2,919,044
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	2,905,796					2,905,796
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
Other debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		4,400		9,438			4,400
Available-for-sale Securities, Fair Value		4,151		9,212			4,151
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	26	[2]		0	[1]
Available-for-sale Securities, Gross Unrealized Loss		(249)	[1]	(252)	[2]		(249)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		0	[3]	$ 0	[4]		0	[3]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Amortized Cost		0					0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost		4,400					4,400
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis		4,400					4,400
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less Than One Year, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value		0					0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value		4,151					4,151
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Fair value		$ 4,151					$ 4,151
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Nominal Yield		0.00%					0.00%
Available-for-sale Securities, Debt Maturities, Greater Than Ten Years, Nominal Yield		1.71%					1.71%
Available-for-sale Securities, Debt Maturities, Nominal Yield		1.71%					1.71%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	[6]	31.66					31.66
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		2		2			2
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0		$ 0			$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		4,151		4,150			4,151
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		4,151		4,150			4,151
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0		0			0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		249		252			249
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		249		252			249
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		4,400					4,400
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		4,151					4,151
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
Residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		5,989,207		6,703,664			5,989,207
Available-for-sale Securities, Fair Value		6,037,469		6,812,841			6,037,469
Available-for-sale Securities, Gross Unrealized Gain		70,448	[1]	121,079	[2]		70,448	[1]
Available-for-sale Securities, Gross Unrealized Loss		(21,359)	[1]	(11,238)	[2]		(21,359)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		(827)	[3]	$ (664)	[4]		(827)	[3]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		5,989,207					5,989,207
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair value		$ 6,037,469					$ 6,037,469
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	[9]	1.95%					1.95%
Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities		3 years 9 months 21 days
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		122		57			122
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 2,279,654		$ 340,631			$ 2,279,654
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		215,636		904,144			215,636
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,495,290		1,244,775			2,495,290
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		17,040		903			17,040
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		5,146		10,999			5,146
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		22,186		11,902			22,186
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	5,861,096					5,861,096
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	5,898,351					5,898,351
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		128,111					128,111
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		139,118					139,118
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
U.S. government agency residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		5,861,096		6,549,304			5,861,096
Available-for-sale Securities, Fair Value		5,898,351		6,646,884			5,898,351
Available-for-sale Securities, Gross Unrealized Gain		58,614	[1]	108,818	[2]		58,614	[1]
Available-for-sale Securities, Gross Unrealized Loss		(21,359)	[1]	(11,238)	[2]		(21,359)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]		$ 0	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		110		45			110
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 2,279,654		$ 329,354			$ 2,279,654
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		197,890		894,124			197,890
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		2,477,544		1,223,478			2,477,544
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		17,040		596			17,040
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		4,319		10,642			4,319
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		21,359		11,238			21,359
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	5,861,096					5,861,096
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	5,898,351					5,898,351
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
U.S. government agency residential mortgage-backed securities [Member] | FHLMC [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		1,940,915		1,810,476			1,940,915
Available-for-sale Securities, Fair Value		1,949,335		1,836,870			1,949,335
Available-for-sale Securities, Gross Unrealized Gain		14,727	[1]	29,043	[2]		14,727	[1]
Available-for-sale Securities, Gross Unrealized Loss		(6,307)	[1]	(2,649)	[2]		(6,307)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]		$ 0	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		40		16			40
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 726,713		$ 62,950			$ 726,713
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		77,545		310,834			77,545
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		804,258		373,784			804,258
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		4,827		37			4,827
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		1,480		2,612			1,480
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		6,307		2,649			6,307
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	1,940,915					1,940,915
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	1,949,335					1,949,335
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
U.S. government agency residential mortgage-backed securities [Member] | GNMA [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		763,967		801,820			763,967
Available-for-sale Securities, Fair Value		761,801		807,443			761,801
Available-for-sale Securities, Gross Unrealized Gain		2,385	[1]	8,240	[2]		2,385	[1]
Available-for-sale Securities, Gross Unrealized Loss		(4,551)	[1]	(2,617)	[2]		(4,551)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]		$ 0	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		15		5			15
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 364,919		$ 8,550			$ 364,919
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		102,109		128,896			102,109
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		467,028		137,446			467,028
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		1,951		12			1,951
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		2,600		2,605			2,600
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		4,551		2,617			4,551
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	763,967					763,967
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	761,801					761,801
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
U.S. government agency residential mortgage-backed securities [Member] | FNMA [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		3,156,214		3,932,200			3,156,214
Available-for-sale Securities, Fair Value		3,187,215		3,997,428			3,187,215
Available-for-sale Securities, Gross Unrealized Gain		41,502	[1]	71,200	[2]		41,502	[1]
Available-for-sale Securities, Gross Unrealized Loss		(10,501)	[1]	(5,972)	[2]		(10,501)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]		$ 0	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		55		24			55
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 1,188,022		$ 257,854			$ 1,188,022
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		18,236		454,394			18,236
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		1,206,258		712,248			1,206,258
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		10,262		547			10,262
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		239		5,425			239
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		10,501		5,972			10,501
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	3,156,214					3,156,214
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	3,187,215					3,187,215
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
U.S. government agency residential mortgage-backed securities [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		0		4,808			0
Available-for-sale Securities, Fair Value		0		5,143			0
Available-for-sale Securities, Gross Unrealized Gain		0	[1]	335	[2]		0	[1]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]		0	[1]
Available-for-sale Securities, Other Than Temporary Impairments		0	[3]	0	[4]		0	[3]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
Privately issued residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		128,111		154,360			128,111
Available-for-sale Securities, Fair Value		139,118		165,957			139,118
Available-for-sale Securities, Gross Unrealized Gain		11,834	[1]	12,261	[2]		11,834	[1]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]		0	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ (827)	[3]	$ (664)	[4]		$ (827)	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		12	[10]	12	[11]		12	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0	[10]	$ 11,277	[11]		$ 0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		17,746	[10]	10,020	[11]		17,746	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		17,746	[10]	21,297	[11]		17,746	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0	[10]	307	[11]		0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		827	[10]	357	[11]		827	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		827	[10]	$ 664	[11]		827	[10]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		128,111					128,111
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		139,118					139,118
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		$ 0					$ 0
Other Than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Assumptions Used to Develop Projected Cash Flows [Abstract]
Unemployment rate		Decreasing to 4.8% over the next 12 months and remain at 4.8% thereafter.		Held constant at 5.6% over the next 12 months and remain at 5.6% thereafter.
Housing price appreciation/depreciation	[12]	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.5% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter.		Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 3.2% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter.
Estimated liquidation costs		Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.		Reflect actual historical liquidations costs observed on Jumbo and Alt-A residential mortgage loans in securities owned by the Company.
Discount rates		Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields.		Estimated cash flows were discounted at rates that range from 2.00% to 6.25% based on our current expected yields.
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Privately Issued Mortgage-backed Securities [Abstract]
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Number of Securities		44					44
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Credit Losses Recognized [Abstract]
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Number of Securities with Credit Losses		4					43
Available-for-sale Securities, Other than Temporary Impairment Losses, Credit Losses Recognized		$ (157)		$ 0		(938)	$ (54,504)
Privately issued residential mortgage-backed securities [Member] | Alt A [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		56,387		65,582			56,387
Available-for-sale Securities, Fair Value		62,574		71,952			62,574
Available-for-sale Securities, Gross Unrealized Gain		6,574	[1]	6,677	[2]		6,574	[1]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]		0	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ (387)	[3]	$ (307)	[4]		$ (387)	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		4	[10]	4	[11]		4	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0	[10]	$ 11,277	[11]		$ 0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		9,264	[10]	0	[11]		9,264	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		9,264	[10]	11,277	[11]		9,264	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0	[10]	307	[11]		0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		387	[10]	0	[11]		387	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		387	[10]	307	[11]		387	[10]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		56,387					56,387
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		62,574					62,574
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		$ 0					$ 0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Privately Issued Mortgage-backed Securities [Abstract]
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Number of Securities		14					14
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Credit Losses Recognized [Abstract]
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Number of Securities with Credit Losses		4					14
Available-for-sale Securities, Other than Temporary Impairment Losses, Credit Losses Recognized		$ (157)					$ (36,284)
Privately issued residential mortgage-backed securities [Member] | Jumbo A Loans [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		71,724		88,778			71,724
Available-for-sale Securities, Fair Value		76,544		94,005			76,544
Available-for-sale Securities, Gross Unrealized Gain		5,260	[1]	5,584	[2]		5,260	[1]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	0	[2]		0	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ (440)	[3]	$ (357)	[4]		$ (440)	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		8	[10]	8	[11]		8	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0	[10]	$ 0	[11]		$ 0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		8,482	[10]	10,020	[11]		8,482	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		8,482	[10]	10,020	[11]		8,482	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0	[10]	0	[11]		0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		440	[10]	357	[11]		440	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		440	[10]	357	[11]		440	[10]
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		71,724					71,724
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		76,544					76,544
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		$ 0					$ 0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized in Earnings, Net, Qualitative Disclosures, Privately Issued Mortgage-backed Securities [Abstract]
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Number of Securities		30					30
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Credit Losses Recognized [Abstract]
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Number of Securities with Credit Losses		0					29
Available-for-sale Securities, Other than Temporary Impairment Losses, Credit Losses Recognized		$ 0					$ (18,220)
Perpetual preferred stock, equity securities and mutual funds [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis		34,292					34,292
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair value		$ 37,505					$ 37,505
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield		0.00%					0.00%
Perpetual preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		$ 17,171		22,171			$ 17,171
Available-for-sale Securities, Fair Value		19,672		24,277			19,672
Available-for-sale Securities, Gross Unrealized Gain		2,501	[1]	2,183	[2]		2,501	[1]
Available-for-sale Securities, Gross Unrealized Loss		0	[1]	(77)	[2]		0	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]		$ 0	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		0		2			0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 0		$ 2,898			$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0			0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		0		2,898			0
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0		77			0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0			0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0		77			0
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		6,406					6,406
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		7,429					7,429
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		10,765					10,765
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		12,243					12,243
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		0					0
Equity securities and mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		17,121		18,603			17,121
Available-for-sale Securities, Fair Value		17,833		19,444			17,833
Available-for-sale Securities, Gross Unrealized Gain		752	[1]	871	[2]		752	[1]
Available-for-sale Securities, Gross Unrealized Loss		(40)	[1]	(30)	[2]		(40)	[1]
Available-for-sale Securities, Other Than Temporary Impairments		$ 0	[3]	$ 0	[4]		$ 0	[3]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Securities		61		68			61
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 782		$ 0			$ 782
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		991		1,205			991
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		1,773		1,205			1,773
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		5		0			5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		35		30			35
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		40		30			40
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities, Portion Recognized In Earnings, Net Qualitative Disclosures, Lowest Current Credit Rating [Abstract]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Amortized Cost	[5]	0					0
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	[5]	0					0
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost		4					4
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value		478					478
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost		0					0
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value		0					0
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost		17,117					17,117
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value		17,355					$ 17,355
Available-for-sale Securities, Privately Issued Residential Mortgage-backed Securities, Credit Losses Recognized [Abstract]
Available-for-sale Securities, Other than Temporary Impairment Losses, Credit Losses Recognized		$ (1,700)		$ (373)		$ 0

[1] Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.

[2] Gross unrealized gain/loss recognized in AOCI in the consolidated balance sheet.

[3] Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.

[4] Amounts represent unrealized loss that remains in AOCI after an other-than-temporary credit loss has been recognized in income.

[5] U.S. government and government sponsored enterprises are not rated by the nationally-recognized rating agencies as these securities are guaranteed by agencies of the U.S. government or government-sponsored enterprises.

[6] Expected maturities may differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without penalty.

[7] Calculated on a taxable equivalent basis using a 39% effective tax rate.

[8] Nominal yield on municipal and other tax-exempt securities and other debt securities with contractual maturity dates over ten years are based on variable rates which generally are reset within 35 days.

[9] The nominal yield on mortgage-backed securities is based upon prepayment assumptions at the purchase date. Actual yields earned may differ significantly based upon actual prepayments. See Quarterly Financial Summary –– Unaudited following for current yields on available for sale securities portfolio.

[10] Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.

[11] Includes securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income.

[12] Federal Housing Finance Agency