DEPOSITS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2021
Money market deposit accounts	$ 847,430	$ 905,196
Time deposits	172,682	137,015
Negotiable order of withdrawal accounts	113,052	137,833
Savings accounts	5,289	5,620
Total interest bearing deposits	1,138,453	1,185,664
Aggregate time deposits of $250,000 or greater	73,401	64,902
Overdrafts balances classified As loans	100	$ 100
Simmons Bank
Deposits acquired via acquisitions	$ 63,100