INCOME TAXES - Components of Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets
Allowance for loan losses	$ 6,704	$ 8,731
Deferred compensation	1,494	1,648
Deferred gain on interest rate swap	114	296
Unrealized loss on interest rate swap	80	342
Nonaccrual interest	5	17
Purchase accounting adjustments	5,631	13,444
Goodwill and intangible assets	4,909	7,488
Other real estate owned	3,203	6,244
Net operating loss tax carryforward	17,853	26,414
AMT credit carryforward	813	813
Unrealized loss on securities available for sale	508	665
Capitalized costs, accrued expenses and other	1,144	680
Deferred tax assets, net of valuation allowance, total	42,458	66,782
Deferred tax liabilities
Depreciation and amortization	4,064	6,188
Mortgage servicing rights	1,885	1,412
Subordinated debentures	5,147	9,428
FDIC-assisted transaction adjustments	3,042	8,978
Deferred tax liabilities, net	14,138	26,006
Net deferred tax asset	$ 28,320	$ 40,776