LOANS - Categorized by Internally Assigned Risk Grades (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Loans by class categorized by internally assigned risk grades
Total loans	$ 4,638,110	$ 3,672,596
2020	1,244,540
2019	794,850
2018	392,271
2017	591,437
2016	323,297
2015 and prior	843,052
Revolving	419,659
Revolving Term	29,004
Total	4,638,110
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
Commercial real estate occupied:
Loans by class categorized by internally assigned risk grades
Total loans		1,565,687
Commercial real estate occupied: | Owner
Loans by class categorized by internally assigned risk grades
Total loans		531,088
Commercial real estate occupied: | Owner | Pass
Loans by class categorized by internally assigned risk grades
Total loans		511,444
Commercial real estate occupied: | Owner | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		18,426
Commercial real estate occupied: | Owner | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		1,218
Commercial real estate occupied: | Non-owner
Loans by class categorized by internally assigned risk grades
Total loans		1,034,599
Commercial real estate occupied: | Non-owner | Pass
Loans by class categorized by internally assigned risk grades
Total loans		1,022,208
Commercial real estate occupied: | Non-owner | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		12,391
Commercial real estate occupied: | Mortgage loans | Owner
Loans by class categorized by internally assigned risk grades
Total loans	528,118	531,088
2020	51,453
2019	93,467
2018	60,015
2017	89,784
2016	32,817
2015 and prior	200,582
Total	528,118
Commercial real estate occupied: | Mortgage loans | Owner | Pass
Loans by class categorized by internally assigned risk grades
2020	50,692
2019	92,079
2018	52,528
2017	67,356
2016	28,019
2015 and prior	169,380
Total	460,054
Commercial real estate occupied: | Mortgage loans | Owner | Watch
Loans by class categorized by internally assigned risk grades
2020	761
2019	1,388
2018	6,884
2017	11,003
2016	1,263
2015 and prior	27,354
Total	48,653
Commercial real estate occupied: | Mortgage loans | Owner | Special Mention
Loans by class categorized by internally assigned risk grades
2017	11,425
2016	3,535
2015 and prior	3,550
Total	18,510
Commercial real estate occupied: | Mortgage loans | Owner | Substandard
Loans by class categorized by internally assigned risk grades
2018	603
2015 and prior	298
Total	901
Commercial real estate occupied: | Mortgage loans | Non-owner
Loans by class categorized by internally assigned risk grades
Total loans	1,064,623	1,034,599
2020	84,516
2019	258,026
2018	132,849
2017	207,272
2016	75,077
2015 and prior	306,883
Total	1,064,623
Commercial real estate occupied: | Mortgage loans | Non-owner | Pass
Loans by class categorized by internally assigned risk grades
2020	84,516
2019	254,026
2018	129,900
2017	195,406
2016	60,157
2015 and prior	291,068
Total	1,015,073
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	2,348
2016	14,920
2015 and prior	14,428
Total	38,645
Commercial real estate occupied: | Mortgage loans | Non-owner | Special Mention
Loans by class categorized by internally assigned risk grades
2015 and prior	291
Total	291
Commercial real estate occupied: | Mortgage loans | Non-owner | Substandard
Loans by class categorized by internally assigned risk grades
2017	9,518
2015 and prior	1,096
Total	10,614
Multi-family
Loans by class categorized by internally assigned risk grades
Total loans		812,174
2020	87,165
2019	293,188
2018	41,121
2017	124,748
2016	159,458
2015 and prior	138,386
Total	844,066
Multi-family | Pass
Loans by class categorized by internally assigned risk grades
Total loans		811,770
2020	87,165
2019	293,188
2018	41,121
2017	116,556
2016	143,747
2015 and prior	125,006
Total	806,783
Multi-family | Watch
Loans by class categorized by internally assigned risk grades
2017	8,192
2016	15,711
2015 and prior	12,984
Total	36,887
Multi-family | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		404
2015 and prior	396
Total	396
Multi-family | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	844,066	812,174
Residential real estate
Loans by class categorized by internally assigned risk grades
Total loans	469,183	493,144
2020	12,579
2019	34,489
2018	82,955
2017	103,694
2016	29,224
2015 and prior	140,316
Revolving	54,072
Revolving Term	11,854
Total	469,183
Residential real estate | Pass
Loans by class categorized by internally assigned risk grades
Total loans		475,949
2020	12,579
2019	32,911
2018	81,473
2017	102,888
2016	28,647
2015 and prior	125,921
Revolving	53,274
Revolving Term	8,958
Total	446,651
Residential real estate | Watch
Loans by class categorized by internally assigned risk grades
2019	465
2018	410
2017	324
2016	577
2015 and prior	2,397
Revolving Term	1,466
Total	5,639
Residential real estate | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		12,400
2019	1,113
2018	766
2015 and prior	5,750
Revolving	798
Revolving Term	729
Total	9,156
Residential real estate | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		4,795
2018	306
2017	482
2015 and prior	6,248
Revolving Term	701
Total	7,737
Residential real estate | Mortgage loans
Loans by class categorized by internally assigned risk grades
Total loans	469,183	493,144
Commercial, industrial and agricultural
Loans by class categorized by internally assigned risk grades
Total loans	1,625,651	679,444
2020	999,280
2019	80,474
2018	62,471
2017	45,324
2016	26,709
2015 and prior	50,949
Revolving	344,602
Revolving Term	15,842
Total	1,625,651
Commercial, industrial and agricultural | Pass
Loans by class categorized by internally assigned risk grades
Total loans		643,413
2020	993,996
2019	77,773
2018	46,573
2017	36,174
2016	25,748
2015 and prior	37,948
Revolving	298,735
Revolving Term	7,323
Total	1,524,270
Commercial, industrial and agricultural | Watch
Loans by class categorized by internally assigned risk grades
2020	5,284
2019	2,318
2018	14,770
2017	3,251
2016	413
2015 and prior	2,718
Revolving	37,069
Revolving Term	462
Total	66,285
Commercial, industrial and agricultural | Special Mention
Loans by class categorized by internally assigned risk grades
Total loans		15,670
2019	383
2018	760
2017	818
2016	548
2015 and prior	764
Revolving	8,798
Revolving Term	3,042
Total	15,113
Commercial, industrial and agricultural | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		20,361
2018	368
2017	5,081
2015 and prior	9,519
Revolving Term	5,015
Total	19,983
Real estate construction and land loans
Loans by class categorized by internally assigned risk grades
Total loans	81,516	97,311
2020	9,090
2019	34,264
2018	12,612
2017	20,478
2015 and prior	5,072
Total	81,516
Real estate construction and land loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans		95,530
2020	9,090
2019	34,264
2018	8,662
2017	17,940
2015 and prior	4,674
Total	74,630
Real estate construction and land loans | Watch
Loans by class categorized by internally assigned risk grades
2018	3,950
2017	1,560
2015 and prior	279
Total	5,789
Real estate construction and land loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		1,781
2017	978
2015 and prior	119
Total	1,097
Installment/consumer loans
Loans by class categorized by internally assigned risk grades
Total loans	24,953	24,836
2020	457
2019	942
2018	248
2017	137
2016	12
2015 and prior	864
Revolving	20,985
Revolving Term	1,308
Total	24,953
Installment/consumer loans | Pass
Loans by class categorized by internally assigned risk grades
Total loans		23,976
2020	457
2019	942
2018	248
2017	128
2016	12
2015 and prior	864
Revolving	20,985
Revolving Term	414
Total	24,050
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	100
Total	100
Installment/consumer loans | Substandard
Loans by class categorized by internally assigned risk grades
Total loans		$ 757
2017	9
Revolving Term	749
Total	$ 758