OTHER COMPREHENSIVE INCOME - AOCI Changes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Summary of the AOCI balances, net of tax
Balance at beginning of period	$ 784,046	$ 717,091	$ 764,244	$ 689,934
Current Year Change	795	1,465	6,528	4,259
Balance at end of period	795,619	731,428	795,619	731,428
Accumulated Other Comprehensive Income
Summary of the AOCI balances, net of tax
Balance at beginning of period	8,831	1,797	3,098	(997)
Current Year Change			6,528	4,259
Balance at end of period	9,626	3,262	9,626	3,262
Unrealized gain (loss) on AFS debt securities
Summary of the AOCI balances, net of tax
Balance at beginning of period			2,211	(2,165)
Current Year Change			6,657	4,480
Balance at end of period	8,868	2,315	8,868	2,315
Unrealized gain (loss) on AFS debt security for which a portion of OTTI has been recognized in earnings
Summary of the AOCI balances, net of tax
Balance at beginning of period			964	1,078
Current Year Change			(81)	(27)
Balance at end of period	883	1,051	883	1,051
Unrealized gain (loss) on cash flow hedges
Summary of the AOCI balances, net of tax
Balance at beginning of period			(77)	90
Current Year Change			(48)	(194)
Balance at end of period	$ (125)	$ (104)	$ (125)	$ (104)