BUSINESS COMBINATIONS - Summary of Acquired Identifiable Assets and Liabilities (Details) - USD ($) $ in Thousands			12 Months Ended
	Apr. 03, 2020	Nov. 01, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Liabilities and equity:
Bargain purchase gain			$ (7,835)	$ 0	$ 0
Goodwill resulting from acquisition			$ 156,944	$ 158,572	$ 89,750	$ 19,960
SWG
Purchase price:
Cash and stock	$ 47,860
Total purchase price	47,860
Identifiable assets:
Cash and due from banks	29,247
Investments	89,737
Loans	392,292
Core deposit intangible	4,556
Personal and real property	18,558
Bank owned life insurance	6,963
Other assets	3,402
Total assets	544,755
Liabilities and equity:
Deposits	476,099
Borrowed funds	9,500
Other liabilities	3,461
Total liabilities	489,060
Net assets acquired	55,695
Consideration paid	47,860
Bargain purchase gain	(7,835)
Goodwill resulting from acquisition	$ (7,835)
First Florida Bancorp, Inc
Purchase price:
Total purchase price		$ 89,520
Identifiable assets:
Cash and due from banks		50,169
Investments		122,084
Loans		247,263
Core deposit intangible		3,745
Personal and real property		4,991
Other assets		3,619
Total assets		431,871
Liabilities and equity:
Deposits		373,908
Borrowed funds		5,527
Other liabilities		1,324
Total liabilities		380,759
Net assets acquired		51,112
Consideration paid		89,520
Goodwill resulting from acquisition		38,408
First Florida Bancorp, Inc | Reported Value Measurement [Member]
Purchase price:
Total purchase price		89,520
Identifiable assets:
Cash and due from banks		50,169
Investments		122,084
Loans		247,263
Core deposit intangible		3,745
Personal and real property		4,991
Other assets		2,283
Total assets		430,535
Liabilities and equity:
Deposits		373,908
Borrowed funds		5,527
Other liabilities		1,619
Total liabilities		381,054
Net assets acquired		49,481
Consideration paid		89,520
Goodwill resulting from acquisition		40,039
First Florida Bancorp, Inc | Changes Measurement [Member]
Purchase price:
Total purchase price		0
Identifiable assets:
Cash and due from banks		0
Investments		0
Loans		0
Core deposit intangible		0
Personal and real property		0
Other assets		1,336
Total assets		1,336
Liabilities and equity:
Deposits		0
Borrowed funds		0
Other liabilities		(295)
Total liabilities		(295)
Net assets acquired		1,631
Consideration paid		0
Goodwill resulting from acquisition		$ (1,631)