SUMMARY OF ORGANIZATION - Additional information (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended
	Aug. 24, 2020	May 26, 2020	Feb. 21, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
SUMMARY OF ORGANIZATION
Total assets				$ 5,164,159		$ 5,164,159			$ 3,941,863
Loans, including Loans held for sale				3,144,000		3,144,000
Deposits				4,229,214		4,229,214			3,076,533
Stockholders' equity				638,369	$ 478,088	638,369	$ 478,088	$ 627,795	$ 543,658	$ 466,281	$ 363,254
Net income				$ 11,917	$ 12,272	37,171	$ 31,890
Noncash Merger Related Costs						$ 2,500
Dividends on common stock, per share	$ 0.10	$ 0.10	$ 0.10