Seacoast Banking Corporation of Florida (Parent Company Only) Financial Information - Summary of Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income
Total Interest Income	$ 287,035	$ 289,823	$ 241,398
Interest expense	24,292	46,205	29,883
Other expenses	15,835	15,177	17,222
Income tax benefit	22,818	29,873	20,259
Net Income	77,764	98,739	67,275
Parent Company
Income
Interest/other	270	679	484
Dividends from subsidiary Bank	0	0	0
Total Interest Income	270	679	484
Interest expense	2,236	3,368	3,165
Other expenses	838	651	879
Total expenses	3,074	4,019	4,044
Loss before income taxes and equity in undistributed income of subsidiaries	(2,804)	(3,340)	(3,560)
Income tax benefit	(589)	(702)	(747)
Loss before equity in undistributed income of subsidiaries	(2,215)	(2,638)	(2,813)
Equity in undistributed income of subsidiaries	79,979	101,377	70,088
Net Income	$ 77,764	$ 98,739	$ 67,275