Investment Securities - Securities Held-to-Maturity Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022	Sep. 30, 2023		Sep. 30, 2022	Dec. 31, 2022
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period	$ 1,500		$ 1,500	$ 1,500	[1]	$ 0
Provision for Credit Losses	0		0	0		1,500
Charge-offs	0		0	0		0
Recoveries	0		0	0		0
Allowance for Credit Losses, End of Period	1,500	[2]	1,500	1,500	[2]	1,500
Debt Securities, Held-to-maturity, Fair Value	2,013,295	[2]		2,013,295	[2]		$ 2,110,472	[1]
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	[2]		0	[2]		8	[1]
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(269,291)	[2]		(269,291)	[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			0
Debt Securities, Held-to-maturity, Fair Value	165,663			165,663			171,700
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0			0			0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(20,645)			(20,645)			(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			140
Debt Securities, Held-to-maturity, Fair Value	1,118,071			1,118,071			1,165,785
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0			0			8
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(128,038)			(128,038)			(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			0
Debt Securities, Held-to-maturity, Fair Value	378,582			378,582			393,124
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0			0			0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(53,609)			(53,609)			(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			0
Debt Securities, Held-to-maturity, Fair Value	302,662			302,662			319,798
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0			0			0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(46,634)			(46,634)			(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			1,360
Debt Securities, Held-to-maturity, Fair Value	48,317			48,317			60,065
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0			0			0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(20,365)			(20,365)			$ (8,369)
Municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period	140		140	140		0
Provision for Credit Losses	0		0	0		140
Charge-offs	0		0	0		0
Recoveries	0		0	0		0
Allowance for Credit Losses, End of Period	140		140	140		140
Corporate Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Allowance for Credit Losses, Beginning of Period	1,360		1,360	1,360		0
Provision for Credit Losses	0		0	0		1,360
Charge-offs	0		0	0		0
Recoveries	0		0	0		0
Allowance for Credit Losses, End of Period	$ 1,360		$ 1,360	$ 1,360		$ 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 September 30, 2023 which is recorded in "Other assets" on the condensed consolidated balance sheets