LOAN SERVICING RIGHTS - Schedule of Carrying Value of Loan Servicing Rights Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Servicing Assets at Fair Value [Line Items]
Loan servicing rights	$ 96,784		$ 103,035
Residential mortgage
Servicing Assets at Fair Value [Line Items]
Loan servicing rights	91,381	$ 85,922	94,902	$ 11,185	$ 12,104	$ 11,814
SBA
Servicing Assets at Fair Value [Line Items]
Loan servicing rights	5,241	5,394	7,886	3,110	3,042	3,012
Indirect automobile
Servicing Assets at Fair Value [Line Items]
Loan servicing rights	$ 162	$ 204	$ 247	$ 0	$ 0	$ 0