SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Premises and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Buildings
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years
Furniture, Fixtures, And Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Furniture, Fixtures, And Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	7 years