Available for Sale Securities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended						63 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 9,918,277		$ 10,830,525				$ 9,918,277		$ 10,185,091
Available-for-sale Securities, Fair Value	9,933,723		11,059,145				9,933,723		10,147,162
Available-for-sale Securities, Gross Unrealized Gain	117,860	[1]	237,272	[1]			117,860	[1]	120,120	[1]
Available-for-sale Securities, Gross Unrealized Loss	(101,822)	[1]	(5,833)	[1]			(101,822)	[1]	(155,607)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(592)	[2]	(2,819)	[2]			(592)	[2]	(2,442)	[2]
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.76%						1.76%
Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract]
Available-for-sale Securities, Proceeds	531,385		728,424
Available-for-sale Securities, Gross realized gains	6,433		5,792
Available-for-sale Securities, Gross realized losses	(5,193)		(936)
Available-for-sale Securities, Related federal and state income tax expense	482		1,889
Available-for-sale Securities, Pledged as Collateral [Abstract]
Available-for-sale Securities, Pledged As Collateral, Amortized cost	5,177,411		4,415,455				5,177,411		5,171,782
Available-for-sale Securities, Pledged As Collateral, Fair value	5,169,432		4,524,553				5,169,432		5,133,530
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	415		147				415		446
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	5,308,753		1,534,539				5,308,753		6,230,595
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	243,975		60,145				243,975		50,865
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	5,552,728		1,594,684				5,552,728		6,281,460
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	94,112		6,136				94,112		156,172
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	8,302		2,516				8,302		1,877
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	102,414		8,652				102,414		158,049
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	9,598,037	[3]					9,598,037	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	9,600,365	[3]					9,600,365	[3]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost	51,112						51,112
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	52,442						52,442
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	53,028						53,028
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	54,082						54,082
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost	190,267						190,267
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	201,060						201,060
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost	25,833						25,833
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	25,774						25,774
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,265,202						2,265,202
Available-for-sale Securities, Fair Value	2,229,980						2,229,980
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis	29,231						29,231
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	777,681						777,681
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	1,062,256						1,062,256
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	396,034						396,034
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value	29,473						29,473
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value	771,737						771,737
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value	1,039,371						1,039,371
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value	389,399						389,399
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	2.01%						2.01%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	1.37%						1.37%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	1.48%						1.48%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.29%						1.29%
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.42%						1.42%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	8.98	[4]					8.98	[4]
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	1,033		1,000				1,033		1,042
Available-for-sale Securities, Fair Value	1,034		1,000				1,034		1,042
Available-for-sale Securities, Gross Unrealized Gain	1	[1]	0	[1]			1	[1]	0	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]			0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis	1,033						1,033
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	0						0
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	0						0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	0						0
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value	1,034						1,034
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	0						0
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	0.24%						0.24%
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, Over Ten Years, Nominal Yield	0.00%						0.00%
Available-for-sale Securities, Debt Maturities, Nominal Yield	0.24%						0.24%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	0.88	[4]					0.88	[4]
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	1,033	[3]					1,033	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	1,034	[3]					1,034	[3]
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 Basis	69,434		84,831				69,434		73,232
Available-for-sale Securities, Fair Value	70,065		85,447				70,065		73,775
Available-for-sale Securities, Gross Unrealized Gain	1,548	[1]	2,377	[1]			1,548	[1]	1,606	[1]
Available-for-sale Securities, Gross Unrealized Loss	(917)	[1]	(1,263)	[1]			(917)	[1]	(1,063)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	(498)	[2]			0	[2]	0	[2]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis	3,204						3,204
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	33,928						33,928
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	2,751						2,751
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	29,551						29,551
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value	3,245						3,245
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value	35,096						35,096
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value	2,967						2,967
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value	28,757						28,757
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	4.11%	[5]					4.11%	[5]
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	3.97%	[5]					3.97%	[5]
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	6.26%	[5]					6.26%	[5]
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.59%	[5],[6]					1.59%	[5],[6]
Available-for-sale Securities, Debt Maturities, Nominal Yield	3.05%	[5]					3.05%	[5]
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	9.85	[4]					9.85	[4]
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						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 Positions	29		53	[7]			29		27
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, OTTI Portion, Number of Positions			21
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	13,750		10,390	[7]			13,750		13,286
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	16,601		29,724	[7]			16,601		17,805
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	30,351		40,114	[7]			30,351		31,091
Available-for-sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, OTTI Portion, Fair Value			7,424
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, OTTI Portion, Fair Value			4,462
Available-for-sale Securities, Continuous Unrealized Loss Position, OTTI Portion, Fair Value			11,886
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	198		397	[7]			198		245
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	719		1,364	[7]			719		818
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	917		1,761	[7]			917		1,063
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses			310
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, OTTI Portion, Aggregate Losses			188
Available-for-sale Securities, Continuous Unrealized Loss Position, OTTI Portion, Aggregate Losses			498
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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost	46,208						46,208
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	47,268						47,268
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	11,491						11,491
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	11,206						11,206
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	11,735						11,735
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	11,591						11,591
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 Basis	2,159,704		1,402,594				2,159,704		2,100,146
Available-for-sale Securities, Fair Value	2,123,762		1,405,346				2,123,762		2,055,804
Available-for-sale Securities, Gross Unrealized Gain	1,329	[1]	4,693	[1]			1,329	[1]	1,042	[1]
Available-for-sale Securities, Gross Unrealized Loss	(37,271)	[1]	(1,941)	[1]			(37,271)	[1]	(45,384)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis	0						0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	738,616						738,616
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	1,059,505						1,059,505
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	361,583						361,583
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	731,428						731,428
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value	1,036,404						1,036,404
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value	355,930						355,930
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	1.25%						1.25%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	1.47%						1.47%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.26%						1.26%
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.36%						1.36%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	9.02	[4]					9.02	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	128		49				128		123
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	1,545,035		604,290				1,545,035		1,800,717
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	207,246		0				207,246		2,286
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,752,281		604,290				1,752,281		1,803,003
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	30,151		1,941				30,151		45,302
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7,120		0				7,120		82
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	37,271		1,941				37,271		45,384
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	2,159,704	[3]					2,159,704	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	2,123,762	[3]					2,123,762	[3]
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 Basis	35,031		35,650				35,031		35,061
Available-for-sale Securities, Fair Value	35,119		36,079				35,119		35,241
Available-for-sale Securities, Gross Unrealized Gain	275	[1]	635	[1]			275	[1]	368	[1]
Available-for-sale Securities, Gross Unrealized Loss	(187)	[1]	(206)	[1]			(187)	[1]	(188)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Amortized Cost Basis	24,994						24,994
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	5,137						5,137
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	0						0
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	4,900						4,900
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value	25,194						25,194
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value	5,213						5,213
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	4,712						4,712
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	1.74%						1.74%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	2.12%						2.12%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	0.00%						0.00%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.64%	[6]					1.64%	[6]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.78%						1.78%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	5.07	[4]					5.07	[4]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	3		4				3		3
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	481		4,712				481		4,712
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,231		481				4,231		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	4,712		5,193				4,712		4,712
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	19		187				19		188
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	168		19				168		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	187		206				187		188
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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost	4,900						4,900
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	4,712						4,712
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	30,131						30,131
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	30,407						30,407
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 Basis	7,616,802		9,264,827				7,616,802		7,934,370
Available-for-sale Securities, Fair Value	7,664,817		9,481,420				7,664,817		7,937,109
Available-for-sale Securities, Gross Unrealized Gain	111,995	[1]	221,332	[1]			111,995	[1]	114,073	[1]
Available-for-sale Securities, Gross Unrealized Loss	(63,388)	[1]	(2,418)	[1]			(63,388)	[1]	(108,892)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(592)	[2]	(2,321)	[2]			(592)	[2]	(2,442)	[2]
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.87%	[8]					1.87%	[8]
Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities	3 years 6 months						3 years 6 months
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	149		38				149		174
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	3,747,709		914,549				3,747,709		4,404,822
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	15,725		29,940				15,725		30,774
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,763,434		944,489				3,763,434		4,435,596
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	63,696		3,606				63,696		110,357
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	284		1,133				284		977
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	63,980		4,739				63,980		111,334
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	7,437,300	[3]					7,437,300	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	7,475,569	[3]					7,475,569	[3]
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	179,502						179,502
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	189,248						189,248
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. agency residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	7,437,300		8,957,389				7,437,300		7,720,189
Available-for-sale Securities, Fair Value	7,475,569		9,165,212				7,475,569		7,716,010
Available-for-sale Securities, Gross Unrealized Gain	101,657	[1]	210,102	[1]			101,657	[1]	104,713	[1]
Available-for-sale Securities, Gross Unrealized Loss	(63,388)	[1]	(2,279)	[1]			(63,388)	[1]	(108,892)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	136		26				136		158
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	3,735,965		875,087				3,735,965		4,379,137
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	3,735,965		875,087				3,735,965		4,379,137
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	63,388		2,279				63,388		108,892
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	63,388		2,279				63,388		108,892
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	7,437,300	[3]					7,437,300	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	7,475,569	[3]					7,475,569	[3]
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. agency residential mortgage-backed securities [Member] | Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	4,380,066		5,036,888				4,380,066		4,224,327
Available-for-sale Securities, Fair Value	4,409,566		5,161,971				4,409,566		4,232,332
Available-for-sale Securities, Gross Unrealized Gain	65,393	[1]	127,362	[1]			65,393	[1]	68,154	[1]
Available-for-sale Securities, Gross Unrealized Loss	(35,893)	[1]	(2,279)	[1]			(35,893)	[1]	(60,149)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	77		26				77		81
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	2,075,587		875,087				2,075,587		2,281,491
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,075,587		875,087				2,075,587		2,281,491
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	35,893		2,279				35,893		60,149
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	35,893		2,279				35,893		60,149
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	4,380,066	[3]					4,380,066	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	4,409,566	[3]					4,409,566	[3]
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. agency residential mortgage-backed securities [Member] | Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,158,750		2,747,896				2,158,750		2,308,341
Available-for-sale Securities, Fair Value	2,162,580		2,809,286				2,162,580		2,293,943
Available-for-sale Securities, Gross Unrealized Gain	25,644	[1]	61,390	[1]			25,644	[1]	25,813	[1]
Available-for-sale Securities, Gross Unrealized Loss	(21,814)	[1]	0	[1]			(21,814)	[1]	(40,211)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	45		0				45		50
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	1,236,653		0				1,236,653		1,450,588
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,236,653		0				1,236,653		1,450,588
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	21,814		0				21,814		40,211
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	21,814		0				21,814		40,211
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	2,158,750	[3]					2,158,750	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	2,162,580	[3]					2,162,580	[3]
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. agency residential mortgage-backed securities [Member] | Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	885,058		1,044,086				885,058		1,151,225
Available-for-sale Securities, Fair Value	888,989		1,060,870				888,989		1,152,128
Available-for-sale Securities, Gross Unrealized Gain	9,612	[1]	16,784	[1]			9,612	[1]	9,435	[1]
Available-for-sale Securities, Gross Unrealized Loss	(5,681)	[1]	0	[1]			(5,681)	[1]	(8,532)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	14		0				14		27
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	423,725		0				423,725		647,058
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	423,725		0				423,725		647,058
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	5,681		0				5,681		8,532
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	5,681		0				5,681		8,532
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	885,058	[3]					885,058	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	888,989	[3]					888,989	[3]
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. agency residential mortgage-backed securities [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	13,426		128,519				13,426		36,296
Available-for-sale Securities, Fair Value	14,434		133,085				14,434		37,607
Available-for-sale Securities, Gross Unrealized Gain	1,008	[1]	4,566	[1]			1,008	[1]	1,311	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]			0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
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	13,426	[3]					13,426	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	14,434	[3]					14,434	[3]
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 Basis	179,502		307,438				179,502		214,181
Available-for-sale Securities, Fair Value	189,248		316,208				189,248		221,099
Available-for-sale Securities, Gross Unrealized Gain	10,338	[1]	11,230	[1]			10,338	[1]	9,360	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	(139)	[1]			0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(592)	[2]	(2,321)	[2]			(592)	[2]	(2,442)	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	13	[9]	12	[7]			13	[9]	16	[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	11,744	[9]	39,462	[7]			11,744	[9]	25,685	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	15,725	[9]	29,940	[7]			15,725	[9]	30,774	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	27,469	[9]	69,402	[7]			27,469	[9]	56,459	[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	308	[9]	1,327	[7]			308	[9]	1,465	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	284	[9]	1,133	[7]			284	[9]	977	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	592	[9]	2,460	[7]			592	[9]	2,442	[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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
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	179,502						179,502
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	189,248						189,248
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	Held constant at 7.3% over the next 12 months and remains at 7.3% thereafter.		Increasing to 8% over the next 12 months and remain at 8% thereafter.		Increasing to 7.3% over the next 12 months and remain at 7.3% thereafter.
Housing price appreciation/depreciation	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 4% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter.	[11]	Starting with current depreciated housing prices based on information derived from the FHFA1, depreciating 2% over the next 12 months, then flat for he following 12 months and then appreciating at 2% per year thereafter.	[11]	Starting with current depreciated housing prices based on information derived from the FHFA1, appreciating 4% over the next 12 months, then flat for the following 12 months and then appreciating at 2% per year thereafter.	[11]
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.		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.		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	45						45
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 In Current Period	0						43
Amount of Credit Losses Recognized in Current Period	0						54,347
Privately issued residential mortgage-backed securities [Member] | Alt-A [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	73,244		119,373				73,244		104,559
Available-for-sale Securities, Fair Value	77,557		124,164				77,557		107,212
Available-for-sale Securities, Gross Unrealized Gain	4,597	[1]	5,198	[1]			4,597	[1]	4,386	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]			0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(284)	[2]	(407)	[2]			(284)	[2]	(1,733)	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	5	[9]	1	[7]			5	[9]	7	[10]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, OTTI Portion, Number of Positions	5		1				5		7
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	[9]	0	[7]			0	[9]	11,043	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	15,725	[9]	3,500	[7]			15,725	[9]	30,774	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	15,725	[9]	3,500	[7]			15,725	[9]	41,817	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, OTTI Portion, Fair Value	0		0				0		11,043
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, OTTI Portion, Fair Value	15,725		3,500				15,725		30,774
Available-for-sale Securities, Continuous Unrealized Loss Position, OTTI Portion, Fair Value	15,725		3,500				15,725		41,817
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	[9]	0	[7]			0	[9]	756	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	284	[9]	407	[7]			284	[9]	977	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	284	[9]	407	[7]			284	[9]	1,733	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	0		0				0		756
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, OTTI Portion, Aggregate Losses	284		407				284		977
Available-for-sale Securities, Continuous Unrealized Loss Position, OTTI Portion, Aggregate Losses	284		407				284		1,733
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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
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	73,244						73,244
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	77,557						77,557
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 In Current Period	0						14
Amount of Credit Losses Recognized in Current Period	0						36,127
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 Basis	106,258		188,065				106,258		109,622
Available-for-sale Securities, Fair Value	111,691		192,044				111,691		113,887
Available-for-sale Securities, Gross Unrealized Gain	5,741	[1]	6,032	[1]			5,741	[1]	4,974	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	(139)	[1]			0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(308)	[2]	(1,914)	[2]			(308)	[2]	(709)	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	8	[9]	11	[7]			8	[9]	9	[10]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, OTTI Portion, Number of Positions	8		10				8		9
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	11,744	[9]	39,462	[7]			11,744	[9]	14,642	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	[9]	26,440	[7]			0	[9]	0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	11,744	[9]	65,902	[7]			11,744	[9]	14,642	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less Than Twelve Months, OTTI Portion, Fair Value	11,744		39,462				11,744		14,642
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, OTTI Portion, Fair Value	0		13,248				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, OTTI Portion, Fair Value	11,744		52,710				11,744		14,642
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	308	[9]	1,327	[7]			308	[9]	709	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	[9]	726	[7]			0	[9]	0	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	308	[9]	2,053	[7]			308	[9]	709	[10]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Losses	308		1,327				308		709
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, OTTI Portion, Aggregate Losses	0		587				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, OTTI Portion, Aggregate Losses	308		1,914				308		709
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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
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	106,258						106,258
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	111,691						111,691
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	31						31
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 In Current Period	0						29
Amount of Credit Losses Recognized in Current Period	0						18,220
Perpetual Preferred, Equity Securities and Mutual Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	36,273						36,273
Available-for-sale Securities, Fair Value	38,926						38,926
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.44%						1.44%
Perpetual preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis	22,171		22,171				22,171		22,171
Available-for-sale Securities, Fair Value	24,281		26,832				24,281		22,863
Available-for-sale Securities, Gross Unrealized Gain	2,110	[1]	4,661	[1]			2,110	[1]	705	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]			0	[1]	(13)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	0		0				0		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	0		0				0		4,988
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	0		0				0		4,988
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		13
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0		0				0		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0		0				0		13
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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
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	11,406						11,406
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	12,469						12,469
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	11,812						11,812
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 Basis	14,102		19,452				14,102		19,069
Available-for-sale Securities, Fair Value	14,645		23,021				14,645		21,328
Available-for-sale Securities, Gross Unrealized Gain	602	[1]	3,574	[1]			602	[1]	2,326	[1]
Available-for-sale Securities, Gross Unrealized Loss	(59)	[1]	(5)	[1]			(59)	[1]	(67)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	0	[2]	0	[2]			0	[2]	0	[2]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	106		3				106		118
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	1,778		598				1,778		2,070
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	172		0				172		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,950		598				1,950		2,070
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	48		5				48		67
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	11		0				11		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	59		5				59		67
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	0	[3]					0	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	0	[3]					0	[3]
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	462						462
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	14,098						14,098
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	$ 14,183						$ 14,183

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

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

[3] 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.

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

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

[6] 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.

[7] Includes the following securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income:Municipal and other tax-exempt 21 $7,424 $310 $4,462 $188 $11,886 $498Alt-A loans 1 — — 3,500 407 3,500 407Jumbo-A loans 10 39,462 1,327 13,248 587 52,710 1,914

[8] 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.

[9] Includes the following securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income:Alt-A loans 5 — — 15,725 284 15,725 284Jumbo-A loans 8 11,744 308 — — 11,744 308

[10] Includes the following securities for which an unrealized loss remains in AOCI after an other-than-temporary credit loss has been recognized in income:Alt-A loans 7 $11,043 $756 $30,774 $977 $41,817 $1,733Jumbo-A loans 9 14,642 709 — — 14,642 709

[11] Federal Housing Finance Agency