Goodwill and Other Intangible Assets - Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Total	$ 108,795	$ 112,645
Core Deposit Premium
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	177,624	187,467
Accumulated amortization	(79,722)	(86,123)
Total	97,902	101,344	$ 116,016
Books of Business Intangible
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	22,068	22,068
Accumulated amortization	(11,175)	(10,767)
Total	$ 10,893	$ 11,301	$ 12,935