Investment Securities - Securities Held-to-Maturity (Details) - USD ($) $ in Thousands		Jun. 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]	$ 2,261,867
Debt Securities, Held-to-maturity, Allowance for Credit Loss	[1]	(1,500)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		2,260,367	[1]	$ 0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	[1]	554
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	[1]	(51,162)
Debt Securities, Held-to-maturity, Fair Value	[1]	2,209,759
Municipal securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		1,241,664
Debt Securities, Held-to-maturity, Allowance for Credit Loss		(140)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		1,241,524
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		554
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(36,762)
Debt Securities, Held-to-maturity, Fair Value		1,205,316
Agency commercial MBS
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		424,274
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		424,274
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(4,626)
Debt Securities, Held-to-maturity, Fair Value		419,648
Private label commercial MBS
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		343,545
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		343,545
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(5,663)
Debt Securities, Held-to-maturity, Fair Value		337,882
U.S. Treasury securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		182,751
Debt Securities, Held-to-maturity, Allowance for Credit Loss		0
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		182,751
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(1,855)
Debt Securities, Held-to-maturity, Fair Value		180,896
Corporate debt securities
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss		69,633
Debt Securities, Held-to-maturity, Allowance for Credit Loss		(1,360)
Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss		68,273
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain		0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss		(2,256)
Debt Securities, Held-to-maturity, Fair Value		66,017
Interest Receivable		$ 13,700

[1] Excludes accrued interest receivable of $13.7 million at June 30, 2022 which is recorded in "Other assets" on the condensed consolidated balance sheets