Seacoast Banking Corporation of Florida (Parent Company Only) Financial Information - Summary of Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Other assets	$ 6,400
Total Assets	7,108,511	$ 6,747,659
Liabilities and Shareholders' Equity
Subordinated debt	71,085	70,804
Shareholders' equity	985,639	864,267	$ 689,664	$ 435,397
Total Liabilities & Shareholders' Equity	7,108,511	6,747,659
Parent Company
Assets
Cash	70	197
Securities purchased under agreement to resell with subsidiary bank, maturing within 30 days	52,979	40,130
Investment in subsidiaries	1,005,756	897,683
Other assets	1,515	777
Total Assets	1,060,320	938,787
Liabilities and Shareholders' Equity
Subordinated debt	71,085	70,804
Other liabilities	3,700	3,716
Shareholders' equity	985,535	864,267
Total Liabilities & Shareholders' Equity	$ 1,060,320	$ 938,787