Securities - Schedule of Debt Securities (Details) - USD ($)	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 5,079,053,000	$ 5,161,904,000
Unrealized Gains	22,000	172,000
Unrealized Losses	(791,490,000)	(754,555,000)
Allowance for Credit Losses	0	0	$ 0
Fair Value	4,287,585,000	4,407,521,000
Government-sponsored residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,229,111,000	3,302,165,000
Unrealized Gains	0	0
Unrealized Losses	(545,484,000)	(521,527,000)
Allowance for Credit Losses	0	0
Fair Value	2,683,627,000	2,780,638,000
Government-sponsored commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,315,886,000	1,326,029,000
Unrealized Gains	0	0
Unrealized Losses	(209,103,000)	(201,653,000)
Allowance for Credit Losses	0	0
Fair Value	1,106,783,000	1,124,376,000
U.S. Agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	236,761,000	236,454,000
Unrealized Gains	0	0
Unrealized Losses	(21,523,000)	(20,443,000)
Allowance for Credit Losses	0	0
Fair Value	215,238,000	216,011,000
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	99,610,000	99,552,000
Unrealized Gains	0	0
Unrealized Losses	(4,525,000)	(4,400,000)
Allowance for Credit Losses	0	0
Fair Value	95,085,000	95,152,000
State and municipal bonds and obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	197,685,000	197,704,000
Unrealized Gains	22,000	172,000
Unrealized Losses	(10,855,000)	(6,532,000)
Allowance for Credit Losses	0	0
Fair Value	$ 186,852,000	$ 191,344,000