Investment Securities - Securities Held-to-Maturity Allowance for Credit Losses (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2023		Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period	[1]	$ 1,500
Provision for Credit Losses		0
Charge-offs		0
Recoveries		0
Allowance for Credit Losses, End of Period	[2]	1,500
Debt Securities, Held-to-maturity, Fair Value		2,157,056	[2]	$ 2,110,472	[1]
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		814	[2]	8	[1]
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(117,408)	[2]	(158,671)	[1]
U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		0
Allowance for Credit Losses, End of Period		0
Debt Securities, Held-to-maturity, Fair Value		176,629		171,700
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(8,233)		(12,462)
Municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		140
Allowance for Credit Losses, End of Period		140
Debt Securities, Held-to-maturity, Fair Value		1,203,912		1,165,785
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		814		8
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(41,203)		(77,526)
Agency commercial MBS
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		0
Allowance for Credit Losses, End of Period		0
Debt Securities, Held-to-maturity, Fair Value		402,860		393,124
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(26,135)		(34,287)
Private label commercial MBS
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		0
Allowance for Credit Losses, End of Period		0
Debt Securities, Held-to-maturity, Fair Value		318,605		319,798
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(28,371)		(26,027)
Corporate Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		1,360
Allowance for Credit Losses, End of Period		1,360
Debt Securities, Held-to-maturity, Fair Value		55,050		60,065
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(13,466)		$ (8,369)
Municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		140
Provision for Credit Losses		0
Charge-offs		0
Recoveries		0
Allowance for Credit Losses, End of Period		140
Corporate Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period		1,360
Provision for Credit Losses		0
Charge-offs		0
Recoveries		0
Allowance for Credit Losses, End of Period		$ 1,360

[1] Excludes accrued interest receivable of $13.5 million at December 31, 2022 which is recorded in "Other assets" on the condensed consolidated balance sheets

[2] Excludes accrued interest receivable of $11.3 million at March 31, 2023 which is recorded in "Other assets" on the condensed consolidated balance sheets