Business Combinations - Narrative (Details)				3 Months Ended
	Jan. 31, 2023 USD ($) branch	Oct. 07, 2022 USD ($) branch	Jan. 03, 2022 USD ($) branch	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Business Acquisition [Line Items]
Allowance for credit losses				$ 155,640,000	$ 89,838,000	$ 113,895,000	$ 83,315,000
Goodwill				728,396,000		$ 480,319,000
Acquisition costs				$ 17,500,000	$ 6,700,000
Professional Holding Corp.
Business Acquisition [Line Items]
Number of branches operated | branch	9
Percentage of common stock acquired	100.00%
Common stock portion, number of Seacoast stock for each share of stock converted (in shares)	0.8909
Goodwill recognized from acquisition, nondeductible	$ 248,100,000
Fair value of options and warrants converted	10,304,000
Allowance for credit losses	39,900,000
Goodwill	248,091,000
Professional Holding Corp. | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses at acquisition	13,335,000
Professional Holding Corp. | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses	$ 26,600,000
Apollo Bancshares, Inc.
Business Acquisition [Line Items]
Number of branches operated | branch		5
Common stock portion, number of Seacoast stock for each share of stock converted (in shares)		1.006529
Goodwill recognized from acquisition, nondeductible		$ 90,200,000
Fair value of options and warrants converted		$ 6,530,000
Minority interest portion, number of Seacoast stock for each share of stock converted (in shares)		1.195651
Allowance for credit losses		$ 7,800,000
Goodwill		90,237,000
Apollo Bancshares, Inc. | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses at acquisition		2,658,000
Apollo Bancshares, Inc. | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses		$ 5,100,000
Drummond Banking Company
Business Acquisition [Line Items]
Number of branches operated | branch		18
Percentage of common stock acquired		100.00%
Common stock portion, number of Seacoast stock for each share of stock converted (in shares)		51.9561
Allowance for credit losses		$ 12,500,000
Goodwill		103,476,000
Drummond Banking Company | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses at acquisition		2,566,000
Drummond Banking Company | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses		$ 9,900,000
Business Bank of Florida
Business Acquisition [Line Items]
Number of branches operated | branch			1
Percentage of common stock acquired			100.00%
Common stock portion, number of Seacoast stock for each share of stock converted (in shares)			0.7997
Goodwill recognized from acquisition, nondeductible			$ 8,000,000
Fair value of options and warrants converted			497,000
Allowance for credit losses			1,800,000
Goodwill			7,962,000
Business Bank of Florida | Stock Option | Seacoast 2021 Incentive Plan
Business Acquisition [Line Items]
Fair value of options and warrants converted			500,000
Business Bank of Florida | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			15,000
Allowance for credit losses at acquisition			15,000
Business Bank of Florida | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			$ 1,800,000
Sabal Palm Bancorp, Inc.
Business Acquisition [Line Items]
Number of branches operated | branch			3
Percentage of common stock acquired			100.00%
Common stock portion, number of Seacoast stock for each share of stock converted (in shares)			0.2203
Goodwill recognized from acquisition, nondeductible			$ 26,500,000
Fair value of options and warrants converted			3,336,000
Allowance for credit losses			3,400,000
Goodwill			26,489,000
Sabal Palm Bancorp, Inc. | Stock Option | Seacoast 2021 Incentive Plan
Business Acquisition [Line Items]
Fair value of options and warrants converted			3,300,000
Sabal Palm Bancorp, Inc. | PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			37,000
Allowance for credit losses at acquisition			37,000
Sabal Palm Bancorp, Inc. | Acquired Non-PCD Loans
Business Acquisition [Line Items]
Allowance for credit losses			$ 3,400,000