Shareholders' Equity - Summary of Required Regulatory Capital (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Parent Company [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to risk-weighted assets), Amount	$ 322,765	$ 227,310
Total Capital (to risk-weighted assets), Ratio	16.25%	16.88%
Total Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Amount	158,903	107,757
Total Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Ratio	8.00%	8.00%
Tier 1 Capital (to risk-weighted assets), Amount	305,665	210,433
Tier 1 Capital (to risk-weighted assets), Ratio	15.39%	15.62%
Tier 1 Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Amount	79,452	53,878
Tier 1 Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Ratio	4.00%	4.00%
Trust preferred securities issued	305,665	210,433
Tier 1 Capital (to adjusted average assets), Ratio	10.32%	9.59%
Tier 1 Capital (to adjusted average assets), Minimum for Capital Adequacy Purpose, Amount	124,731	92,234
Tier 1 Capital (to adjusted average assets), Minimum for Capital Adequacy Purpose, Ratio	4.00%	4.00%
Total Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	0	0
Total Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.00%	0.00%
Tier 1 Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	0	0
Tier 1 Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.00%	0.00%
Tier 1 Capital (to adjusted average assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	0	0
Tier 1 Capital (to adjusted average assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.00%	0.00%
Seacoast National Bank (A Wholly Owned Bank Subsidiary) [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital (to risk-weighted assets), Amount	284,555	225,102
Total Capital (to risk-weighted assets), Ratio	14.32%	16.74%
Total Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Amount	158,925	107,571
Total Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Ratio	8.00%	8.00%
Tier 1 Capital (to risk-weighted assets), Amount	267,455	208,253
Tier 1 Capital (to risk-weighted assets), Ratio	13.46%	15.49%
Tier 1 Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Amount	79,462	53,785
Tier 1 Capital (to risk-weighted assets), Minimum for Capital Adequacy Purpose, Ratio	4.00%	4.00%
Trust preferred securities issued	267,455	208,253
Tier 1 Capital (to adjusted average assets), Ratio	9.04%	9.51%
Tier 1 Capital (to adjusted average assets), Minimum for Capital Adequacy Purpose, Amount	118,409	87,636
Tier 1 Capital (to adjusted average assets), Minimum for Capital Adequacy Purpose, Ratio	4.00%	4.00%
Total Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	198,656	134,463
Total Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	10.00%	10.00%
Tier 1 Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	119,193	80,678
Tier 1 Capital (to risk-weighted assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.00%	6.00%
Tier 1 Capital (to adjusted average assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount	$ 148,011	$ 109,545
Tier 1 Capital (to adjusted average assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	5.00%	5.00%