FAIR VALUE DISCLOSURES - Assets and Liabilities Measured At Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Assets:
Total Securities	$ 1,239,715
Total Securities		$ 734,845
Mortgage banking derivative	15,426	21,764
Interest rate swap derivative	15,426	21,764
Liabilities:
Mortgage banking derivative	15,447	21,794
Interest rate swap derivative	15,447	21,794
Fair Value, Measurements, Recurring
Assets:
U.S. Treasury securities	900
U.S. government sponsored agency securities	116,461	36,487
Mortgage-backed securities: residential	431,833	279,503
Mortgage-backed securities: commercial	24,182	36,881
State and municipal securities	666,339	381,974
Total Securities	1,239,715
Total Securities		734,845
Mortgage banking derivative	719	1,182
Interest rate swap derivative	15,426	21,764
Total assets	1,255,860	757,791
Liabilities:
Mortgage banking derivative	1	111
Interest rate swap derivative	15,447	21,794
Total liabilities	15,448	21,905
Level 1 | Fair Value, Measurements, Recurring
Assets:
U.S. Treasury securities	900
U.S. government sponsored agency securities	0	0
Mortgage-backed securities: residential	0	0
Mortgage-backed securities: commercial	0	0
State and municipal securities	0	0
Total Securities	900
Total Securities		0
Mortgage banking derivative	0	0
Interest rate swap derivative	0	0
Total assets	900	0
Liabilities:
Mortgage banking derivative	0	0
Interest rate swap derivative	0	0
Total liabilities	0	0
Level 2 | Fair Value, Measurements, Recurring
Assets:
U.S. Treasury securities	0
U.S. government sponsored agency securities	116,461	36,487
Mortgage-backed securities: residential	431,833	279,503
Mortgage-backed securities: commercial	24,182	36,881
State and municipal securities	666,199	381,834
Total Securities	1,238,675
Total Securities		734,705
Mortgage banking derivative	719	1,182
Interest rate swap derivative	15,426	21,764
Total assets	1,254,820	757,651
Liabilities:
Mortgage banking derivative	1	111
Interest rate swap derivative	15,447	21,794
Total liabilities	15,448	21,905
Level 3 | Fair Value, Measurements, Recurring
Assets:
U.S. Treasury securities	0
U.S. government sponsored agency securities	0	0
Mortgage-backed securities: residential	0	0
Mortgage-backed securities: commercial	0	0
State and municipal securities	140	140
Total Securities	140
Total Securities		140
Mortgage banking derivative	0	0
Interest rate swap derivative	0	0
Total assets	140	140
Liabilities:
Mortgage banking derivative	0	0
Interest rate swap derivative	0	0
Total liabilities	$ 0	$ 0