BORROWINGS - Schedule of Long-term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amount
Subordinated debt	$ 177,887	$ 120,000
FHLB long-term advances	400,046	241
Capital loan with municipality	775	775
Total long-term debt	$ 570,037	$ 119,654
Average Rate [Abstract]
Debt, Weighted Average Interest Rate	5.13%	5.13%
Federal Home Loan Bank	2.09%	1.09%
Weighted average rate on other long-term debt	0.00%	0.00%
Total long-term debt	3.06%	5.14%
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	$ (8,671)	$ (1,362)

Average Rate [Abstract]

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Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Weighted average interest rate of debt outstanding.

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States the interest rate applicable to Federal Home Loan Bank advances outstanding as of the Balance Sheet date.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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Amount of long-term debt classified as other.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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