INVESTMENT SECURITIES - Equity securities (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019	Jan. 01, 2019
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at fair value		$ 11,970		$ 11,782
CRA Qualified Investment Fund
Debt and Equity Securities, FV-NI [Line Items]
Equity securities, at fair value		12,000		$ 11,800
Equity Securities, FV-NI, Realized Gain		$ 188	$ 144
Accounting Standards Update 2016-01
Debt and Equity Securities, FV-NI [Line Items]
Cumulative effect of change in accounting principal	[1]				$ 0
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities
Debt and Equity Securities, FV-NI [Line Items]
Cumulative effect of change in accounting principal	[1]				399
Accounting Standards Update 2016-01 | Accumulated Other Comprehensive (Loss) Income (Net of Taxes) Available for Sale Securities | CRA Qualified Investment Fund
Debt and Equity Securities, FV-NI [Line Items]
Cumulative effect of change in accounting principal					399
Accounting Standards Update 2016-01 | Retained Earnings
Debt and Equity Securities, FV-NI [Line Items]
Cumulative effect of change in accounting principal	[1]				(399)
Accounting Standards Update 2016-01 | Retained Earnings | CRA Qualified Investment Fund
Debt and Equity Securities, FV-NI [Line Items]
Cumulative effect of change in accounting principal					$ 399

[1] (1) Represents the impact of adopting Accounting Standards Update ("ASU") 2016-01. See Note 2 to the unaudited consolidated financial statements for further information.