Investment (Held-to-Maturity) Securities (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2022 USD ($)		Sep. 30, 2022 USD ($)		Dec. 31, 2021 USD ($)
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Gross Amortized Cost		$ 2,816,352		$ 2,816,352		$ 210,999
Investment Securities, Gross Carrying Value		2,572,972	[1]	2,572,972	[1]	210,999
Investment securities, Allowance for Credit Loss		(612)	[1]	(612)	[1]	(555)
Investment Securities, Amortized Cost, After Allowance for Credit Loss		2,815,740		2,815,740		210,444
Investment Securities, Carrying Value, after Allowance for Credit Loss		2,572,360	[1]	2,572,360	[1]	210,444
Investment Securities, Fair Value		2,407,766		2,407,766		231,395
Investment Securities, Gross Unrealized Gain		5,305		5,305		20,412
Investment Securities, Gross Unrealized Loss		$ (170,511)		(170,511)		$ (16)
Debt Securities, Net Unrealized Loss Remaining in AOCI included in Carrying Value for AFS Securities Transferred to Investment Securities				$ (243,000)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		179		179		3
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 2,267,981		$ 2,267,981		$ 273
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		778		778		587
Investment Securities, Continuous Unrealized Loss Position, Fair Value		2,268,759		2,268,759		860
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		170,412		170,412		2
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		99		99		14
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		170,511		170,511		16
Fixed Maturity Securities [Member]
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investment Securities, Debt Maturities, Less than One Year, Net Carrying Value		23,919		23,919
Investment Securities, Debt Maturities, One to Five Years, Net Carrying Value		102,100		102,100
Investment Securities, Debt Maturities, Six to Ten Years, Net Carrying Value		68,921		68,921
Investment Securities, Debt Maturities, Over Ten Years, Net Carrying Value		4,993		4,993
Investment Securities, Debt Maturities, Single Maturity Date, Net Carrying Value		199,933		199,933
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, Less Than One Year, Fair Value		24,075		24,075
Investment Securities, Debt Maturities, One to Five Years, Fair Value		106,695		106,695
Investment Securities, Debt Maturities, Six to Ten Years, Fair Value		66,693		66,693
Investment Securities, Debt Maturities, Over Ten Years, Fair Value		4,970		4,970
Investment Securities, Debt Maturities, Single Maturity Date, Fair Value		$ 202,433		$ 202,433
Investment Securities, Debt Maturities, Weighted Average Maturity	[2]	4.57		4.57
Municipal securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Gross Amortized Cost		$ 173,113		$ 173,113		203,772
Investment Securities, Gross Carrying Value		173,113	[1]	173,113	[1]	203,772
Investment Securities, Fair Value		176,990		176,990		223,609
Investment Securities, Gross Unrealized Gain		5,138		5,138		19,851
Investment Securities, Gross Unrealized Loss		$ (1,261)		$ (1,261)		$ (14)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		58		58		1
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 39,774		$ 39,774		$ 0
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		519		519		587
Investment Securities, Continuous Unrealized Loss Position, Fair Value		40,293		40,293		587
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		1,178		1,178		0
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		83		83		14
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,261		1,261		14
Residential agency mortgage-backed securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Gross Amortized Cost		2,614,691		2,614,691		6,939
Investment Securities, Gross Carrying Value		2,373,039	[1]	2,373,039	[1]	6,939
Investment Securities, Fair Value		2,205,333		2,205,333		7,500
Investment Securities, Gross Unrealized Gain		167		167		561
Investment Securities, Gross Unrealized Loss		(167,873)		(167,873)		0
Investment Securities, Debt Maturities, Net Carrying Value [Abstract]
Investment Securities, Debt Maturities, without Single Maturity Date, Net Carrying Value	[3]	2,373,039		2,373,039
Investment Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Investment Securities, Debt Maturities, without Single Maturity Date, Fair Value		$ 2,205,333		$ 2,205,333
Investment Securities, Debt Maturities, Average Expected Life of Mortgage-backed Securities		5 years 6 months
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		116		116
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 2,204,036		$ 2,204,036
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value		2,204,036		2,204,036
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		167,873		167,873
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		167,873		167,873
Commercial agency mortgage-backed securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Gross Amortized Cost		17,260		17,260
Investment Securities, Gross Carrying Value	[1]	15,532		15,532
Investment Securities, Fair Value		14,437		14,437
Investment Securities, Gross Unrealized Gain		0		0
Investment Securities, Gross Unrealized Loss		$ (1,095)		$ (1,095)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		2		2
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 14,437		$ 14,437
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		0		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value		14,437		14,437
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		1,095		1,095
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0		0
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		1,095		1,095
Other debt securities [Member]
Schedule of Investment (Held-to-Maturity) Securities [Line Items]
Investment Securities, Gross Amortized Cost		11,288		11,288		288
Investment Securities, Gross Carrying Value		11,288	[1]	11,288	[1]	288
Investment Securities, Fair Value		11,006		11,006		286
Investment Securities, Gross Unrealized Gain		0		0		0
Investment Securities, Gross Unrealized Loss		$ (282)		$ (282)		$ (2)
Investment Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]
Investment Securities, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions		3		3		2
Investment Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value		$ 9,734		$ 9,734		$ 273
Investment Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value		259		259		0
Investment Securities, Continuous Unrealized Loss Position, Fair Value		9,993		9,993		273
Investment Securities, Continuous Unrealized Loss Position, Aggregate Losses [Abstract]
Investment Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		266		266		2
Investment Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		16		16		0
Investment Securities, Continuous Unrealized Loss Position, Accumulated Loss		$ 282		$ 282		$ 2

[1] Carrying value includes $243 million of net unrealized loss which remains in Accumulated other comprehensive income ("AOCI") in the Consolidated Balance Sheets related to certain securities transferred during the second quarter of 2022 from the Available for Sale securities portfolio to the Investment securities portfolio as discussed in greater detail following.

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

[3] The average expected lives of residential mortgage-backed securities were 5.5 years years based upon current prepayment assumptions.