LOANS - Categorized by Internally Assigned Risk Grades (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Loans by class categorized by internally assigned risk grades
Total loans	$ 3,754,203	$ 3,672,596
2020	159,592
2019	809,998
2018	412,654
2017	604,642
2016	346,064
2015 and prior	883,957
Revolving	506,253
Revolving Term	31,043
Total	3,754,203
Pass
Loans by class categorized by internally assigned risk grades
Total loans		3,584,290
Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		47,003
Substandard
Loans by class categorized by internally assigned risk grades
Total loans		41,303
Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Commercial real estate occupied:
Loans by class categorized by internally assigned risk grades
Total loans		1,565,687
Commercial real estate occupied: | Mortgage loans | Owner
Loans by class categorized by internally assigned risk grades
Total loans	529,877	531,088
2020	33,372
2019	95,036
2018	60,460
2017	90,764
2016	33,171
2015 and prior	217,074
Total	529,877
Commercial real estate occupied: | Mortgage loans | Owner | Pass
Loans by class categorized by internally assigned risk grades
Total loans		511,444
2020	33,372
2019	93,641
2018	52,959
2017	74,288
2016	28,317
2015 and prior	183,452
Total	466,029
Commercial real estate occupied: | Mortgage loans | Owner | Watch
Loans by class categorized by internally assigned risk grades
2019	1,395
2018	6,894
2017	5,502
2016	1,277
2015 and prior	29,560
Total	44,628
Commercial real estate occupied: | Mortgage loans | Owner | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		18,426
2017	10,974
2016	3,577
2015 and prior	3,748
Total	18,299
Commercial real estate occupied: | Mortgage loans | Owner | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		1,218
2018	607
2015 and prior	314
Total	921
Commercial real estate occupied: | Mortgage loans | Owner | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Commercial real estate occupied: | Mortgage loans | Non-owner
Loans by class categorized by internally assigned risk grades
Total loans	1,053,901	1,034,599
2020	39,000
2019	259,073
2018	134,628
2017	209,110
2016	92,214
2015 and prior	319,876
Total	1,053,901
Commercial real estate occupied: | Mortgage loans | Non-owner | Pass
Loans by class categorized by internally assigned risk grades
Total loans		1,022,208
2020	39,000
2019	255,073
2018	131,679
2017	197,225
2016	83,651
2015 and prior	302,905
Total	1,009,533
Commercial real estate occupied: | Mortgage loans | Non-owner | Watch
Loans by class categorized by internally assigned risk grades
2019	4,000
2018	2,949
2017	2,367
2016	8,563
2015 and prior	15,560
Total	33,439
Commercial real estate occupied: | Mortgage loans | Non-owner | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		0
2015 and prior	291
Total	291
Commercial real estate occupied: | Mortgage loans | Non-owner | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		12,391
2017	9,518
2015 and prior	1,120
Total	10,638
Commercial real estate occupied: | Mortgage loans | Non-owner | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Multi-family
Loans by class categorized by internally assigned risk grades
Total loans		812,174
2020	38,911
2019	293,962
2018	41,294
2017	125,232
2016	162,103
2015 and prior	139,054
Total	800,556
Multi-family | Pass
Loans by class categorized by internally assigned risk grades
2020	38,911
2019	293,962
2018	41,294
2017	116,995
2016	146,302
2015 and prior	125,591
Total	763,055
Multi-family | Watch
Loans by class categorized by internally assigned risk grades
2017	8,237
2016	15,801
2015 and prior	13,063
Total	37,101
Multi-family | Special Mention
Loans by class categorized by internally assigned risk grades
2015 and prior	400
Total	400
Multi-family | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	800,556	812,174
Multi-family | Mortgage loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans		811,770
Multi-family | Mortgage loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		404
Multi-family | Mortgage loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		0
Multi-family | Mortgage loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Residential real estate
Loans by class categorized by internally assigned risk grades
Total loans	485,492	493,144
2020	8,964
2019	35,836
2018	84,981
2017	110,196
2016	30,066
2015 and prior	148,495
Revolving	55,943
Revolving Term	11,011
Total	485,492
Residential real estate | Pass
Loans by class categorized by internally assigned risk grades
Total loans		475,949
2020	8,964
2019	34,254
2018	83,491
2017	109,387
2016	29,478
2015 and prior	133,888
Revolving	55,145
Revolving Term	8,085
Total	462,692
Residential real estate | Watch
Loans by class categorized by internally assigned risk grades
2019	465
2018	412
2017	326
2016	588
2015 and prior	2,566
Revolving	399
Revolving Term	1,446
Total	6,202
Residential real estate | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		12,400
2019	783
2018	770
2015 and prior	9,883
Revolving	399
Revolving Term	777
Total	12,612
Residential real estate | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		4,795
2019	334
2018	308
2017	483
2015 and prior	2,158
Revolving Term	703
Total	3,986
Residential real estate | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Residential real estate | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	485,492	493,144
Commercial, industrial and agricultural
Loans by class categorized by internally assigned risk grades
Total loans	758,683	679,444
2020	32,089
2019	83,472
2018	64,768
2017	48,789
2016	28,496
2015 and prior	53,416
Revolving	428,976
Revolving Term	18,677
Total	758,683
Commercial, industrial and agricultural | Pass
Loans by class categorized by internally assigned risk grades
Total loans		643,413
2020	30,490
2019	80,671
2018	48,302
2017	39,169
2016	27,080
2015 and prior	40,486
Revolving	385,474
Revolving Term	7,061
Total	658,733
Commercial, industrial and agricultural | Watch
Loans by class categorized by internally assigned risk grades
2020	1,599
2019	2,417
2018	15,041
2017	4,043
2016	812
2015 and prior	2,827
Revolving	34,752
Revolving Term	3,440
Total	64,931
Commercial, industrial and agricultural | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		15,670
2019	384
2018	813
2017	590
2016	604
2015 and prior	573
Revolving	7,752
Revolving Term	3,507
Total	14,223
Commercial, industrial and agricultural | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		20,361
2018	612
2017	4,987
2015 and prior	9,530
Revolving	998
Revolving Term	4,669
Total	20,796
Commercial, industrial and agricultural | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Real estate construction and land loans
Loans by class categorized by internally assigned risk grades
Total loans	100,643	97,311
2020	7,153
2019	41,664
2018	26,269
2017	20,390
2015 and prior	5,167
Total	100,643
Real estate construction and land loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans		95,530
2020	7,153
2019	41,664
2018	23,069
2017	17,292
2015 and prior	4,763
Total	93,941
Real estate construction and land loans | Watch
Loans by class categorized by internally assigned risk grades
2018	3,200
2017	1,728
2015 and prior	283
Total	5,211
Real estate construction and land loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		0
Real estate construction and land loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		1,781
2017	1,370
2015 and prior	121
Total	1,491
Real estate construction and land loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		0
Installment/consumer loans
Loans by class categorized by internally assigned risk grades
Total loans	25,051	24,836
2020	103
2019	955
2018	254
2017	161
2016	14
2015 and prior	875
Revolving	21,334
Revolving Term	1,355
Total	25,051
Installment/consumer loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans		23,976
2020	103
2019	955
2018	254
2017	145
2016	14
2015 and prior	875
Revolving	21,334
Revolving Term	460
Total	24,140
Installment/consumer loans | Watch
Loans by class categorized by internally assigned risk grades
Revolving Term	45
Total	45
Installment/consumer loans | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		103
Revolving Term	101
Total	101
Installment/consumer loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		757
2017	16
Revolving Term	749
Total	$ 765
Installment/consumer loans | Doubtful
Loans by class categorized by internally assigned risk grades
Total loans		$ 0