Available for Sale Securities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended						75 Months Ended
	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014		Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 9,006,068		$ 8,881,990		$ 9,918,277		$ 9,006,068
Available-for-sale Securities, Fair Value	9,158,175		8,978,945		9,933,723		9,158,175
Available-for-sale Securities, Gross Unrealized Gain	165,738	[1]	129,876	[1]	117,860	[1]	165,738	[1]
Available-for-sale Securities, Gross Unrealized Loss	(12,258)	[1]	(32,257)	[1]	(101,822)	[1]	(12,258)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(1,373)	[2]	(664)	[2]	(592)	[2]	(1,373)	[2]
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.84%						1.84%
Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract]
Available-for-sale Securities, Proceeds	334,825				531,385
Available-for-sale Securities, Gross realized gains	4,900				6,433
Available-for-sale Securities, Gross realized losses	(573)				(5,193)
Available-for-sale Securities, Related federal and state income tax expense	1,683				482
Available-for-sale Securities, Pledged as Collateral [Abstract]
Available-for-sale Securities, Pledged As Collateral, Amortized cost	6,065,705		5,855,220		5,177,411		6,065,705
Available-for-sale Securities, Pledged As Collateral, Fair value	6,155,570		5,893,972		5,169,432		6,155,570
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	186		255		415		186
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	225,413		577,473		5,308,753		225,413
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,295,209		2,160,051		243,975		1,295,209
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,520,622		2,737,524		5,552,728		1,520,622
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	1,673		1,446		94,112		1,673
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	11,958		31,475		8,302		11,958
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	13,631		32,921		102,414		13,631
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	8,746,481	[3]					8,746,481	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	8,883,412	[3]					8,883,412	[3]
Available-for-sale securities, Portfolio Concentration Rated AAA To AA, Amortized Cost	42,908						42,908
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	44,203						44,203
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	26,978						26,978
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	27,675						27,675
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Amortized Cost	159,799						159,799
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	172,391						172,391
Available-for-sale Securities, Portfolio Concentration Not Rated, Amortized Cost	29,902						29,902
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	30,494						30,494
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	2,228,688						2,228,688
Available-for-sale Securities, Fair Value	2,235,816						2,235,816
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	14,812						14,812
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	942,010						942,010
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	909,630						909,630
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	362,236						362,236
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value	14,909						14,909
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value	945,596						945,596
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value	915,496						915,496
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value	359,815						359,815
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	3.11%						3.11%
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	1.52%						1.52%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	1.78%						1.78%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.38%						1.38%
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.61%						1.61%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	8.27	[4]					8.27	[4]
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	1,000		1,005		1,033		1,000
Available-for-sale Securities, Fair Value	1,001		1,005		1,034		1,001
Available-for-sale Securities, Gross Unrealized Gain	1	[1]	0	[1]	1	[1]	1	[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	0						0
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	1,000						1,000
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	0						0
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value	1,001						1,001
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	0.00%						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, Over 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	2.80	[4]					2.80	[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	1,000	[3]					1,000	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	1,001	[3]					1,001	[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	60,298		63,018		69,434		60,298
Available-for-sale Securities, Fair Value	60,818		63,557		70,065		60,818
Available-for-sale Securities, Gross Unrealized Gain	1,242	[1]	1,280	[1]	1,548	[1]	1,242	[1]
Available-for-sale Securities, Gross Unrealized Loss	(722)	[1]	(741)	[1]	(917)	[1]	(722)	[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	9,807						9,807
Available-for-sale Securities, Debt Maturities, One to Five Years, Amortized Cost Basis	25,059						25,059
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	2,084						2,084
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	23,348						23,348
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Fair Value	9,904						9,904
Available-for-sale Securities, Debt Maturities, One to Five Years, Fair Value	25,836						25,836
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value	2,295						2,295
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value	22,783						22,783
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	3.61%	[5]					3.61%	[5]
Available-for-sale Securities, Debt Maturities, One to Five Years, Nominal Yield	4.25%	[5]					4.25%	[5]
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	6.35%	[5]					6.35%	[5]
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.94%	[5],[6]					1.94%	[5],[6]
Available-for-sale Securities, Debt Maturities, Nominal Yield	3.32%	[5]					3.32%	[5]
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	8.30	[4]					8.30	[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
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	20		22		29		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	10,217		10,838		13,750		10,217
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	11,705		12,176		16,601		11,705
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	21,922		23,014		30,351		21,922
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		198		27
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	695		729		719		695
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	722		741		917		722
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	38,504						38,504
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	39,556						39,556
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	10,567						10,567
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	10,047						10,047
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	11,227						11,227
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	11,215						11,215
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	2,157,985		2,064,091		2,159,704		2,157,985
Available-for-sale Securities, Fair Value	2,164,842		2,048,609		2,123,762		2,164,842
Available-for-sale Securities, Gross Unrealized Gain	13,849	[1]	4,437	[1]	1,329	[1]	13,849	[1]
Available-for-sale Securities, Gross Unrealized Loss	(6,992)	[1]	(19,919)	[1]	(37,271)	[1]	(6,992)	[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	915,951						915,951
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Amortized Cost Basis	907,546						907,546
Available-for-sale Securities, Debt Maturities, Over Ten Years, Amortized Cost Basis	334,488						334,488
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	918,759						918,759
Available-for-sale Securities, Debt Maturities, Six to Ten Years, Fair Value	913,201						913,201
Available-for-sale Securities, Debt Maturities, Over Ten Years, Fair Value	332,882						332,882
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	1.44%						1.44%
Available-for-sale Securities, Debt Maturities, Six To Ten Years, Nominal Yield	1.77%						1.77%
Available-for-sale Securities, Debt Maturities, Over Ten Years, Nominal Yield	1.33%						1.33%
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.56%						1.56%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	8.24	[4]					8.24	[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	68		104		128		68
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	97,374		223,106		1,545,035		97,374
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	894,815		1,238,376		207,246		894,815
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	992,189		1,461,482		1,752,281		992,189
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	151		454		30,151		151
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	6,841		19,465		7,120		6,841
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	6,992		19,919		37,271		6,992
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	2,157,985	[3]					2,157,985	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	2,164,842	[3]					2,164,842	[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	9,405		9,438		35,031		9,405
Available-for-sale Securities, Fair Value	9,155		9,212		35,119		9,155
Available-for-sale Securities, Gross Unrealized Gain	0	[1]	26	[1]	275	[1]	0	[1]
Available-for-sale Securities, Gross Unrealized Loss	(250)	[1]	(252)	[1]	(187)	[1]	(250)	[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	5,005						5,005
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	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	5,005						5,005
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	4,150						4,150
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Less than One Year, Nominal Yield	2.12%						2.12%
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	1.71%	[6]					1.71%	[6]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.93%						1.93%
Available-for-sale Securities, Debt Maturities, Weighted Average Maturity	15.18	[4]					15.18	[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	2		2		3		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		481		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,150		4,150		4,231		4,150
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	4,150		4,150		4,712		4,150
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		19		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	250		252		168		250
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	250		252		187		250
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	4,400						4,400
Available-for-sale Securities, Portfolio Concentration Rated AAA To AA, Fair Value	4,150						4,150
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Amortized Cost	5,005						5,005
Available-for-sale Securities, Portfolio Concentration Rated A To BBB, Fair Value	5,005						5,005
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	6,736,530		6,703,664		7,616,802		6,736,530
Available-for-sale Securities, Fair Value	6,877,600		6,812,841		7,664,817		6,877,600
Available-for-sale Securities, Gross Unrealized Gain	146,717	[1]	121,079	[1]	111,995	[1]	146,717	[1]
Available-for-sale Securities, Gross Unrealized Loss	(4,274)	[1]	(11,238)	[1]	(63,388)	[1]	(4,274)	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(1,373)	[2]	(664)	[2]	(592)	[2]	(1,373)	[2]
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.92%	[7]					1.92%	[7]
Available-for-sale Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities	3.3
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	30		57		149		30
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	117,798		340,631		3,747,709		117,798
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	383,532		904,144		15,725		383,532
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	501,330		1,244,775		3,763,434		501,330
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	1,495		903		63,696		1,495
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	4,152		10,999		284		4,152
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	5,647		11,902		63,980		5,647
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	6,587,496	[3]					6,587,496	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	6,717,569	[3]					6,717,569	[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	149,034						149,034
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	160,031						160,031
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	6,587,496		6,549,304		7,437,300		6,587,496
Available-for-sale Securities, Fair Value	6,717,569		6,646,884		7,475,569		6,717,569
Available-for-sale Securities, Gross Unrealized Gain	134,347	[1]	108,818	[1]	101,657	[1]	134,347	[1]
Available-for-sale Securities, Gross Unrealized Loss	(4,274)	[1]	(11,238)	[1]	(63,388)	[1]	(4,274)	[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	18		45		136		18
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	107,644		329,354		3,735,965		107,644
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	373,962		894,124		0		373,962
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	481,606		1,223,478		3,735,965		481,606
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	498		596		63,388		498
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,776		10,642		0		3,776
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	4,274		11,238		63,388		4,274
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	6,587,496	[3]					6,587,496	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	6,717,569	[3]					6,717,569	[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	3,844,253		3,932,200		4,380,066		3,844,253
Available-for-sale Securities, Fair Value	3,930,186		3,997,428		4,409,566		3,930,186
Available-for-sale Securities, Gross Unrealized Gain	87,993	[1]	71,200	[1]	65,393	[1]	87,993	[1]
Available-for-sale Securities, Gross Unrealized Loss	(2,060)	[1]	(5,972)	[1]	(35,893)	[1]	(2,060)	[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	8		24		77		8
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	90,133		257,854		2,075,587		90,133
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	125,166		454,394		0		125,166
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	215,299		712,248		2,075,587		215,299
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	464		547		35,893		464
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,596		5,425		0		1,596
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2,060		5,972		35,893		2,060
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	3,844,253	[3]					3,844,253	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	3,930,186	[3]					3,930,186	[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	2,040,364		1,810,476		2,158,750		2,040,364
Available-for-sale Securities, Fair Value	2,079,310		1,836,870		2,162,580		2,079,310
Available-for-sale Securities, Gross Unrealized Gain	39,989	[1]	29,043	[1]	25,644	[1]	39,989	[1]
Available-for-sale Securities, Gross Unrealized Loss	(1,043)	[1]	(2,649)	[1]	(21,814)	[1]	(1,043)	[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	6		16		45		6
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	17,511		62,950		1,236,653		17,511
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	124,912		310,834		0		124,912
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	142,423		373,784		1,236,653		142,423
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	34		37		21,814		34
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,009		2,612		0		1,009
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1,043		2,649		21,814		1,043
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	2,040,364	[3]					2,040,364	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	2,079,310	[3]					2,079,310	[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	698,346		801,820		885,058		698,346
Available-for-sale Securities, Fair Value	703,206		807,443		888,989		703,206
Available-for-sale Securities, Gross Unrealized Gain	6,031	[1]	8,240	[1]	9,612	[1]	6,031	[1]
Available-for-sale Securities, Gross Unrealized Loss	(1,171)	[1]	(2,617)	[1]	(5,681)	[1]	(1,171)	[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	4		5		14		4
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		8,550		423,725		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	123,884		128,896		0		123,884
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	123,884		137,446		423,725		123,884
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		12		5,681		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,171		2,605		0		1,171
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1,171		2,617		5,681		1,171
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	698,346	[3]					698,346	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	703,206	[3]					703,206	[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	4,533		4,808		13,426		4,533
Available-for-sale Securities, Fair Value	4,867		5,143		14,434		4,867
Available-for-sale Securities, Gross Unrealized Gain	334	[1]	335	[1]	1,008	[1]	334	[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	4,533	[3]					4,533	[3]
Available-for-sale Securities, Portfolio Concentration US Govt or GSE Securities Not Rated, Fair Value	4,867	[3]					4,867	[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	149,034		154,360		179,502		149,034
Available-for-sale Securities, Fair Value	160,031		165,957		189,248		160,031
Available-for-sale Securities, Gross Unrealized Gain	12,370	[1]	12,261	[1]	10,338	[1]	12,370	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]	0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(1,373)	[2],[8]	(664)	[2]	(592)	[2]	(1,373)	[2],[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	12	[8]	12	[8]	13	[8]	12	[8]
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	10,154	[8]	11,277	[8]	11,744	[8]	10,154	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,570	[8]	10,020	[8]	15,725	[8]	9,570	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	19,724	[8]	21,297	[8]	27,469	[8]	19,724	[8]
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	997	[8]	307	[8]	308	[8]	997	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	376	[8]	357	[8]	284	[8]	376	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	1,373	[8]	664	[8]	592	[8]	1,373	[8]
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	149,034						149,034
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	160,031						160,031
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 5.6% over the next 12 months and remain at 5.6% thereafter.		Held constant at 5.6% over the next 12 months and remain at 5.6% thereafter.		Held constant at 7.3% over the next 12 months and remains at 7.3% thereafter.
Housing price appreciation/depreciation	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.	[9]	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.	[9]	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.	[9]
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	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 In Current Period	1						43
Amount of Credit Losses Recognized in Current Period	92						54,439
Privately issued residential mortgage-backed securities [Member] | Alt-A [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	63,765		65,582		73,244		63,765
Available-for-sale Securities, Fair Value	69,369		71,952		77,557		69,369
Available-for-sale Securities, Gross Unrealized Gain	6,601	[1]	6,677	[1]	4,597	[1]	6,601	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]	0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(997)	[2]	(307)	[2]	(284)	[2]	(997)	[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	4	[8]	4	[8]	5	[8]	4	[8]
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	10,154	[8]	11,277	[8]	0	[8]	10,154	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	0	[8]	0	[8]	15,725	[8]	0	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	10,154	[8]	11,277	[8]	15,725	[8]	10,154	[8]
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	997	[8]	307	[8]	0	[8]	997	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	[8]	0	[8]	284	[8]	0	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	997	[8]	307	[8]	284	[8]	997	[8]
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	63,765						63,765
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	69,369						69,369
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	1						14
Amount of Credit Losses Recognized in Current Period	92						36,219
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	85,269		88,778		106,258		85,269
Available-for-sale Securities, Fair Value	90,662		94,005		111,691		90,662
Available-for-sale Securities, Gross Unrealized Gain	5,769	[1]	5,584	[1]	5,741	[1]	5,769	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	0	[1]	0	[1]	0	[1]
Available-for-Sale Securities, Other Than Temporary Impairments	(376)	[2]	(357)	[2]	(308)	[2]	(376)	[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	[8]	8	[8]	8	[8]	8	[8]
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	[8]	0	[8]	11,744	[8]	0	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	9,570	[8]	10,020	[8]	0	[8]	9,570	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	9,570	[8]	10,020	[8]	11,744	[8]	9,570	[8]
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	[8]	0	[8]	308	[8]	0	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	376	[8]	357	[8]	0	[8]	376	[8]
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	376	[8]	357	[8]	308	[8]	376	[8]
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	85,269						85,269
Available-for-sale Securities, Portfolio Concentration Rated Below Investment Grade, Fair Value	90,662						90,662
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 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	40,850						40,850
Available-for-sale Securities, Fair Value	44,759						44,759
Available-for-sale Securities, Debt Maturities, Nominal Yield [Abstract]
Available-for-sale Securities, Debt Maturities, Nominal Yield	1.28%						1.28%
Perpetual preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	22,171		22,171		22,171		22,171
Available-for-sale Securities, Fair Value	24,983		24,277		24,281		24,983
Available-for-sale Securities, Gross Unrealized Gain	2,812	[1]	2,183	[1]	2,110	[1]	2,812	[1]
Available-for-sale Securities, Gross Unrealized Loss	0	[1]	(77)	[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, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	0		2		0		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		0
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		2,898		0		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		0
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		77		0		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	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	12,623						12,623
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	12,360						12,360
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	18,679		18,603		14,102		18,679
Available-for-sale Securities, Fair Value	19,776		19,444		14,645		19,776
Available-for-sale Securities, Gross Unrealized Gain	1,117	[1]	871	[1]	602	[1]	1,117	[1]
Available-for-sale Securities, Gross Unrealized Loss	(20)	[1]	(30)	[1]	(59)	[1]	(20)	[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	66		68		106		66
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	24		0		1,778		24
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,007		1,205		172		1,007
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,031		1,205		1,950		1,031
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		48		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	20		30		11		20
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	20		30		59		20
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	497						497
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	18,675						18,675
Available-for-sale Securities, Portfolio Concentration Not Rated, Fair Value	$ 19,279						$ 19,279

[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] 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.

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

[9] Federal Housing Finance Agency