Securities - Summary Of Debt Securities (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 5,257,264,000	$ 7,825,435,000
Unrealized Gains	0	9,000
Unrealized Losses	(995,746,000)	(1,134,666,000)
Allowance for Credit Losses	0	0	$ 0
Fair Value	4,261,518,000	6,690,778,000
Government-sponsored residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,380,463,000	4,855,763,000
Unrealized Gains	0	0
Unrealized Losses	(679,833,000)	(743,855,000)
Allowance for Credit Losses	0	0
Fair Value	2,700,630,000	4,111,908,000
Government-sponsored commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,343,187,000	1,570,119,000
Unrealized Gains	0	0
Unrealized Losses	(254,067,000)	(221,165,000)
Allowance for Credit Losses	0	0
Fair Value	1,089,120,000	1,348,954,000
U.S. Agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	236,149,000	1,100,891,000
Unrealized Gains	0	0
Unrealized Losses	(28,184,000)	(148,409,000)
Allowance for Credit Losses	0	0
Fair Value	207,965,000	952,482,000
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	99,494,000	99,324,000
Unrealized Gains	0	0
Unrealized Losses	(6,275,000)	(6,267,000)
Allowance for Credit Losses	0	0
Fair Value	93,219,000	93,057,000
State and municipal bonds and obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	197,971,000	198,039,000
Unrealized Gains	0	9,000
Unrealized Losses	(27,387,000)	(14,956,000)
Allowance for Credit Losses	0	0
Fair Value	$ 170,584,000	183,092,000
Other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		1,299,000
Unrealized Gains		0
Unrealized Losses		(14,000)
Allowance for Credit Losses		0
Fair Value		$ 1,285,000