ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Premises and Equipment (Details)	12 Months Ended
	Dec. 31, 2021 building
Teton Financial Services
PREMISES AND EQUIPMENT, NET
Number of buildings acquired	3
Minimum | Leasehold improvements, including artwork
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	7 years
Minimum | Furniture/equipment [Member]
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	3 years
Minimum | Software [Member]
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	3 years
Minimum | Teton Financial Services
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	25 years
Maximum | Leasehold improvements, including artwork
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	15 years
Maximum | Furniture/equipment [Member]
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	7 years
Maximum | Software [Member]
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	7 years
Maximum | Teton Financial Services
PREMISES AND EQUIPMENT, NET
Property, Plant and Equipment, Useful Life	50 years