Borrowings - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2023	Oct. 30, 2025	Dec. 31, 2024	Dec. 31, 2022
Debt Instrument [Line Items]
Cash and cash equivalents	$ 388,545			$ 476,607
Secured lines of credit	7,600,000			5,600,000
FHLB borrowings	$ 835,000			$ 245,000
Average interest rate on Federal Home Loan Bank borrowings	4.27%			4.20%
Weighted average interest rate on balances outstanding	3.82%			4.19%
Trust I & II
Debt Instrument [Line Items]
Junior subordinated deferrable interest notes issued	$ 41,200
SBCF Statutory Trust III
Debt Instrument [Line Items]
Junior subordinated deferrable interest notes issued	$ 12,400
Contractual Interest Rate	1.61%
Secured Debt
Debt Instrument [Line Items]
Secured lines of credit	$ 3,400,000			$ 4,000,000
Secured Debt | Federal Reserve Bank Advances
Debt Instrument [Line Items]
Secured lines of credit	2,300,000			2,600,000
Secured Debt | Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Secured lines of credit	1,100,000			1,400,000
Unsecured Debt
Debt Instrument [Line Items]
Secured lines of credit	348,000			348,000
Senior Notes
Debt Instrument [Line Items]
Debt					$ 12,300
Interest rate					5.50%
Unamortized premium			$ 200
Subordinated Debt
Debt Instrument [Line Items]
Debt		$ 25,000
Interest rate		3.375%
Contractual Interest Rate		2.03%
Fair value adjustment		$ (3,900)
Secured Debt, Potential Additional Borrowings
Debt Instrument [Line Items]
Secured lines of credit	$ 3,800,000			$ 1,300,000