Investment Securities - Securities Held-to-Maturity Credit Quality Indicators (Details) $ in Thousands	Jun. 30, 2022 USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	$ 2,261,867	[1]
Standard & Poor's, AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	928,629
Standard & Poor's, AA+ Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	970,486
Standard & Poor's, AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	178,341
Standard & Poor's, A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,997
Standard & Poor's, A- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	23,196
Standard & Poor's, BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	20,985
Standard & Poor's, No Credit Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	48,578
Standard & Poor's, AA- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	89,655
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
Municipal securities | Standard & Poor's, AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	585,084
Municipal securities | Standard & Poor's, AA+ Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	363,461
Municipal securities | Standard & Poor's, AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	178,341
Municipal securities | Standard & Poor's, A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	1,997
Municipal securities | Standard & Poor's, A- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Municipal securities | Standard & Poor's, BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Municipal securities | Standard & Poor's, No Credit Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	23,126
Municipal securities | Standard & Poor's, AA- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	89,655
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
Agency commercial MBS | Standard & Poor's, AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Agency commercial MBS | Standard & Poor's, AA+ Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	424,274
Agency commercial MBS | Standard & Poor's, AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Agency commercial MBS | Standard & Poor's, A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Agency commercial MBS | Standard & Poor's, A- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Agency commercial MBS | Standard & Poor's, BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Agency commercial MBS | Standard & Poor's, No Credit Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Agency commercial MBS | Standard & Poor's, AA- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
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
Private label commercial MBS | Standard & Poor's, AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	343,545
Private label commercial MBS | Standard & Poor's, AA+ Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Private label commercial MBS | Standard & Poor's, AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Private label commercial MBS | Standard & Poor's, A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Private label commercial MBS | Standard & Poor's, A- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Private label commercial MBS | Standard & Poor's, BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Private label commercial MBS | Standard & Poor's, No Credit Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Private label commercial MBS | Standard & Poor's, AA- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
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
U.S. Treasury securities | Standard & Poor's, AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
U.S. Treasury securities | Standard & Poor's, AA+ Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	182,751
U.S. Treasury securities | Standard & Poor's, AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
U.S. Treasury securities | Standard & Poor's, A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
U.S. Treasury securities | Standard & Poor's, A- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
U.S. Treasury securities | Standard & Poor's, BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
U.S. Treasury securities | Standard & Poor's, No Credit Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
U.S. Treasury securities | Standard & Poor's, AA- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
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
Corporate debt securities | Standard & Poor's, AAA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Corporate debt securities | Standard & Poor's, AA+ Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Corporate debt securities | Standard & Poor's, AA Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Corporate debt securities | Standard & Poor's, A Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	0
Corporate debt securities | Standard & Poor's, A- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	23,196
Corporate debt securities | Standard & Poor's, BBB Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	20,985
Corporate debt securities | Standard & Poor's, No Credit Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	25,452
Corporate debt securities | Standard & Poor's, AA- Rating
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-Maturity, Amortized Cost, before Allowance for Credit Loss	$ 0

[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