Investment Securities - Amortized Cost and Fair Values of Investment Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Available-for-Sale [Abstract]
Amortized Cost	$ 22,184
Estimated Fair Value	19,095	$ 20,171
ACL	0
Debt Securities, Held-to-Maturity, Maturity [Abstract]
Amortized Cost	666,103	685,728
Estimated Fair Value	535,799	568,128
Debt Securities, Available-for-Sale and Held-to-Maturity, after Allowance for Credit Loss [Abstract]
Total Amortized Cost	688,287	708,291
Total Gross Unrealized Gains	7	68
Total Gross Unrealized Losses	(133,400)	(120,060)
Total Estimated Fair Value	554,894	588,299
U.S. government-sponsored mortgage-backed securities
Available-for-Sale [Abstract]
Amortized Cost	22,184	22,563
Gross Unrealized Losses	(3,089)	(2,392)
Estimated Fair Value	19,095	20,171
Debt Securities, Held-to-Maturity, Maturity [Abstract]
Amortized Cost	666,103	685,728
Gross Unrealized Gains	7	68
Gross Unrealized Losses	(130,311)	(117,668)
Estimated Fair Value	$ 535,799	$ 568,128