LOANS AND ALLOWANCE FOR LOAN LOSSES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) branch numberOfLoans	Dec. 31, 2018 USD ($) numberOfLoans branch	Dec. 31, 2017 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased loan pools	$ 213,200	$ 262,600
Purchased loan pools principal balance	212,400	260,500
Purchased pool loans unamortized purchase premium	$ 811	$ 2,100
Purchased pool loans, nonaccrual status, number of loans	1	0
Purchased pool loans, principal balance, nonaccrual status	$ 810
Purchased pool loans, troubled debt restructuring, number of loans | numberOfLoans	0	0
Allowance for loan and lease Losses, purchased loan pools	$ 624	$ 732
Loans modified that are not troubled debt restructurings	325,700	111,700
Troubled debt restructurings excluding purchased loans	14,100	11,000
Troubled debt restructurings, previous charge-offs	827	890
Consumer Installment Home Improvement Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	415,000	399,900
Commercial Insurance Premium Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	646,500	413,500
Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	5,075,281	2,588,832
Purchased loans carrying value	5,080,000	2,590,000
Nonaccrual loans	45,023	24,107
Troubled debt restructuring loans	3,725	2,499
Troubled debt restructurings, previous charge-offs	1,100	940
Troubled debt restructurings principal balances	3,700	2,500
Financing receivable, modifications, subsequent default, recorded investment	2,200	2,500
Troubled debt restructuring	$ 21,100	$ 22,200
Financing receivable, modifications, number of contracts | branch	0	0
Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 29,291	$ 17,952
Troubled debt restructuring loans	4,779	2,256
Allowance for loan losses allocated to troubled debt restructurings	1,800	820
Troubled debt restructurings principal balances	4,800	2,300
Financing receivable, modifications, subsequent default, recorded investment	1,900	1,300
Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased loan pools principal balance	810
Minimum | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	100	100	$ 100
Troubled debt restructuring loans	$ 100	$ 100	$ 100