LOANS AND ALLOWANCE FOR LOAN LOSSES - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) contract	Dec. 31, 2015 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchased loan pools	$ 328,200	$ 568,300
Purchased loan pools principal balance	324,400	559,400
Purchased pool loans unamortized purchase premium	3,800	8,900
Allowance for loan and lease Losses, purchased loan pools	1,100	1,800
Loans modified that are not troubled debt restructurings	103,000	69,400
Troubled debt restructurings excluding purchased loans	15,600	18,200
Troubled debt restructurings, previous charge-offs	2,800	1,200
Allowance for loan losses allocated to troubled debt restructurings	1,400	3,100
Consumer Installment Home Improvement Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	273,700	60,800
Commercial Insurance Premium Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	482,500	353,900
Purchased Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	861,595	1,069,191
Purchased loans carrying value	861,600	1,070,000
Purchased loan pools, troubled debt restructuring amount	904	925
Nonaccrual loans	15,428	22,966
Troubled debt restructuring loans	3,635	5,956
Troubled debt restructurings, previous charge-offs	1,200	1,500
Troubled debt restructurings principal balances	3,600	6,000
Financing receivable, modifications, subsequent default, recorded investment	742	1,000
Troubled debt restructuring	24,900	$ 28,100
Financing receivable, modifications, number of contracts | contract		1
Loans Excluding Purchased Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	14,202	$ 18,114
Troubled debt restructuring loans	4,212	4,522
Troubled debt restructurings principal balances	4,200	4,500
Financing receivable, modifications, subsequent default, recorded investment	1,600	3,500
Minimum | Substandard
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	100	100	$ 200
Troubled debt restructuring loans	$ 100	$ 100	$ 100