Goodwill and Other Intangible Assets - Schedule of Goodwill and Other Intangibles (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Total	$ 87,520	$ 97,242
Core deposit premiums:
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	173,305	177,624
Accumulated amortization	(94,227)	(90,049)
Total	79,078	87,575	$ 101,344
Books of business and other intangibles:
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	22,068	22,068
Accumulated amortization	(13,626)	(12,401)
Total	$ 8,442	$ 9,667	$ 11,301