Business Combinations - Narrative (Details) $ in Thousands				12 Months Ended
	Jan. 31, 2023 USD ($) branch	Oct. 07, 2022 USD ($) branch	Jan. 03, 2022 USD ($) branch	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Goodwill				$ 732,417	$ 480,319	$ 252,154	$ 221,176
Fair value of options and warrants converted				10,300	10,400	4,700
Allowance for credit losses				148,931	113,895	83,315	$ 92,733
Acquisition costs				$ 33,200	27,900	$ 7,900
Stock options
Business Acquisition [Line Items]
Fair value of options and warrants converted					$ 10,400
Professional Holding Corp.
Business Acquisition [Line Items]
Number of branches acquired | branch	9
Percentage of common stock acquired	100.00%
Exchange ratio (in shares)	0.8909
Goodwill	$ 251,674
Fair value of options and warrants converted	10,304
Allowance for credit losses	45,500
Measurement Period Adjustments, Loans	(5,544)
Professional Holding Corp. | Stock options
Business Acquisition [Line Items]
Fair value of options and warrants converted	10,300
Professional Holding Corp. | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses at acquisition	18,879
Professional Holding Corp. | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses	$ 26,600
Apollo Bancshares, Inc.
Business Acquisition [Line Items]
Number of branches acquired | branch		5
Exchange ratio (in shares)		1.006529
Goodwill		$ 90,488
Fair value of options and warrants converted		6,530
Allowance for credit losses		7,800
Measurement Period Adjustments, Loans		$ 0
Minority interest portion, number of Seacoast stock for each share of stock converted (in shares)		1.195651
Apollo Bancshares, Inc. | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses at acquisition		$ 2,658
Apollo Bancshares, Inc. | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses		$ 5,100
Drummond Banking Company
Business Acquisition [Line Items]
Number of branches acquired | branch		18
Percentage of common stock acquired		100.00%
Exchange ratio (in shares)		51.9561
Goodwill		$ 103,649
Allowance for credit losses		12,500
Measurement Period Adjustments, Loans		0
Goodwill, nondeductible for tax purposes		103,600
Drummond Banking Company | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses at acquisition		2,566
Drummond Banking Company | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses		$ 9,900
Business Bank of Florida
Business Acquisition [Line Items]
Number of branches acquired | branch			1
Percentage of common stock acquired			100.00%
Exchange ratio (in shares)			0.7997
Goodwill			$ 7,962
Fair value of options and warrants converted			497
Allowance for credit losses			1,800
Goodwill, nondeductible for tax purposes			8,000
Business Bank of Florida | Stock options | Seacoast 2021 Incentive Plan
Business Acquisition [Line Items]
Fair value of options and warrants converted			500
Business Bank of Florida | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			15
Allowance for credit losses at acquisition			15
Business Bank of Florida | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			$ 1,800
Sabal Palm Bancorp, Inc.
Business Acquisition [Line Items]
Number of branches acquired | branch			3
Percentage of common stock acquired			100.00%
Exchange ratio (in shares)			0.2203
Goodwill			$ 26,489
Fair value of options and warrants converted			3,336
Allowance for credit losses			3,400
Goodwill, nondeductible for tax purposes			26,500
Sabal Palm Bancorp, Inc. | Stock options | Seacoast 2021 Incentive Plan
Business Acquisition [Line Items]
Fair value of options and warrants converted			3,300
Sabal Palm Bancorp, Inc. | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			37
Allowance for credit losses at acquisition			37
Sabal Palm Bancorp, Inc. | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			$ 3,400