Investment Securities - Securities Held-to-Maturity (Details) - USD ($) $ in Thousands		Sep. 30, 2022		Dec. 31, 2021
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	[1]	$ 2,266,101
Debt Securities, Held-to-maturity, Allowance for Credit Loss	[1]	(1,500)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		2,264,601	[1]	$ 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	[1]	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	[1]	(203,755)
Debt Securities, Held-to-maturity, Fair Value	[1]	2,060,846
Municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		1,242,427
Debt Securities, Held-to-maturity, Allowance for Credit Loss		(140)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		1,242,287
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(119,417)
Debt Securities, Held-to-maturity, Fair Value		1,122,870
Agency commercial MBS
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		425,831
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		425,831
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(35,662)
Debt Securities, Held-to-maturity, Fair Value		390,169
Private label commercial MBS
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		344,673
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		344,673
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(29,030)
Debt Securities, Held-to-maturity, Fair Value		315,643
U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		183,457
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		183,457
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(13,447)
Debt Securities, Held-to-maturity, Fair Value		170,010
Corporate debt securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		69,713
Debt Securities, Held-to-maturity, Allowance for Credit Loss		(1,360)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		68,353
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(6,199)
Debt Securities, Held-to-maturity, Fair Value		62,154
Interest Receivable		$ 11,300

[1] Excludes accrued interest receivable of $11.3 million at September 30, 2022 which is recorded in "Other assets" on the condensed consolidated balance sheets