CREDIT QUALITY ASSESSMENT (Activity in Allowance for Loan and Lease Losses by Respective Loan Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 53,486	$ 45,257	$ 45,257
Provision (credit) for loan losses	$ 1,633	$ 1,733	1,505	3,730	9,023
Charge-offs			(1,197)	(818)	(1,416)
Recoveries			230	324	622
Net charge-offs			(967)	(494)	(794)
Balance at period end	54,024	$ 48,493	54,024	48,493	53,486
Total loans and leases	$ 6,551,243		$ 6,551,243		$ 6,571,634
Allowance for loans and leases to total loans and leases ratio	0.82%		0.82%		0.81%
Balance of loans specifically evaluated for impairment	$ 21,657		$ 21,657		$ 22,210
Allowance for loans specifically evaluated for impairment	$ 4,777		$ 4,777		$ 4,924
Specific allowance to specific loans ratio	22.06%		22.06%		22.17%
Balance of loans collectively evaluated	$ 6,515,984		$ 6,515,984		$ 6,523,477
Allowance for loans collectively evaluated	49,247		$ 49,247		$ 48,562
Collective allowance to collective loans ratio			0.76%		0.74%
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 13,602		$ 25,947
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Commercial
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 11,377	8,711	$ 8,711
Provision (credit) for loan losses			(61)		2,857
Charge-offs			(776)		(449)
Recoveries			34		258
Net charge-offs			(742)		(191)
Balance at period end	10,574		10,574		11,377
Total loans and leases	$ 772,158		$ 772,158		$ 796,264
Allowance for loans and leases to total loans and leases ratio	1.37%		1.37%		1.43%
Balance of loans specifically evaluated for impairment	$ 7,347		$ 7,347		$ 7,586
Allowance for loans specifically evaluated for impairment	$ 2,945		$ 2,945		$ 3,594
Specific allowance to specific loans ratio	40.08%		40.08%		47.38%
Balance of loans collectively evaluated	$ 762,100		$ 762,100		$ 780,523
Allowance for loans collectively evaluated	7,629		$ 7,629		$ 7,783
Collective allowance to collective loans ratio			1.00%		1.00%
Commercial | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 2,711		$ 8,155
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 2,113	2,383	$ 2,383
Provision (credit) for loan losses			153		203
Charge-offs			(308)		(611)
Recoveries			144		138
Net charge-offs			(164)		(473)
Balance at period end	2,102		2,102		2,113
Total loans and leases	$ 489,176		$ 489,176		$ 517,839
Allowance for loans and leases to total loans and leases ratio	0.43%		0.43%		0.41%
Balance of loans collectively evaluated	$ 488,068		$ 488,068		$ 516,567
Allowance for loans collectively evaluated	2,102		$ 2,102		$ 2,113
Collective allowance to collective loans ratio			0.43%		0.41%
Consumer | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 1,108		$ 1,272
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 5,944	3,501	$ 3,501
Provision (credit) for loan losses			474		2,381
Charge-offs			0		0
Recoveries			4		62
Net charge-offs			4		62
Balance at period end	6,422		6,422		5,944
Total loans and leases	$ 658,709		$ 658,709		$ 681,201
Allowance for loans and leases to total loans and leases ratio	0.97%		0.97%		0.87%
Balance of loans specifically evaluated for impairment	$ 1,990		$ 1,990		$ 3,306
Allowance for loans specifically evaluated for impairment	$ 393		$ 393		$ 0
Specific allowance to specific loans ratio	0.00%		0.00%		0.00%
Balance of loans collectively evaluated	$ 656,719		$ 656,719		$ 677,895
Allowance for loans collectively evaluated	6,029		$ 6,029		$ 5,944
Collective allowance to collective loans ratio			0.92%		0.88%
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 0		$ 0
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 17,603	14,970	$ 14,970
Provision (credit) for loan losses			1,070		2,677
Charge-offs			0		(131)
Recoveries			10		87
Net charge-offs			10		(44)
Balance at period end	18,683		18,683		17,603
Total loans and leases	$ 1,994,027		$ 1,994,027		$ 1,958,395
Allowance for loans and leases to total loans and leases ratio	0.94%		0.94%		0.90%
Balance of loans specifically evaluated for impairment	$ 7,184		$ 7,184		$ 5,355
Allowance for loans specifically evaluated for impairment	$ 1,413		$ 1,413		$ 1,207
Specific allowance to specific loans ratio	19.67%		19.67%		22.54%
Balance of loans collectively evaluated	$ 1,977,069		$ 1,977,069		$ 1,938,712
Allowance for loans collectively evaluated	17,270		$ 17,270		$ 16,396
Collective allowance to collective loans ratio			0.87%		0.85%
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 9,774		$ 14,328
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 6,307	7,178	$ 7,178
Provision (credit) for loan losses			(212)		(871)
Charge-offs			0		0
Recoveries			0		0
Net charge-offs			0		0
Balance at period end	6,095		6,095		6,307
Total loans and leases	$ 1,224,986		$ 1,224,986		$ 1,202,903
Allowance for loans and leases to total loans and leases ratio	0.50%		0.50%		0.52%
Balance of loans specifically evaluated for impairment	$ 3,766		$ 3,766		$ 4,234
Allowance for loans specifically evaluated for impairment	$ 26		$ 26		$ 123
Specific allowance to specific loans ratio	0.69%		0.69%		2.91%
Balance of loans collectively evaluated	$ 1,221,220		$ 1,221,220		$ 1,196,487
Allowance for loans collectively evaluated	6,069		$ 6,069		$ 6,184
Collective allowance to collective loans ratio			0.50%		0.52%
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 0		$ 2,182
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 8,881	7,268	$ 7,268
Provision (credit) for loan losses			297		1,776
Charge-offs			(113)		(225)
Recoveries			34		62
Net charge-offs			(79)		(163)
Balance at period end	9,099		9,099		8,881
Total loans and leases	$ 1,241,081		$ 1,241,081		$ 1,228,247
Allowance for loans and leases to total loans and leases ratio	0.73%		0.73%		0.72%
Balance of loans specifically evaluated for impairment	$ 1,370		$ 1,370		$ 1,729
Allowance for loans specifically evaluated for impairment	0		0		0
Balance of loans collectively evaluated	1,239,702		1,239,702		1,226,508
Allowance for loans collectively evaluated	9,099		$ 9,099		$ 8,881
Collective allowance to collective loans ratio			0.73%		0.72%
Residential Real Estate Portfolio Segment | Residential Mortgage | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 9		$ 10
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%
Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year			$ 1,261	$ 1,246	$ 1,246
Provision (credit) for loan losses			(216)		0
Charge-offs			0		0
Recoveries			4		15
Net charge-offs			4		15
Balance at period end	1,049		1,049		1,261
Total loans and leases	$ 171,106		$ 171,106		$ 186,785
Allowance for loans and leases to total loans and leases ratio	0.61%		0.61%		0.68%
Balance of loans specifically evaluated for impairment	$ 0		$ 0		$ 0
Allowance for loans specifically evaluated for impairment	0		0		0
Balance of loans collectively evaluated	171,106		171,106		186,785
Allowance for loans collectively evaluated	$ 1,049		$ 1,049		$ 1,261
Collective allowance to collective loans ratio			0.61%		0.68%
Residential Real Estate Portfolio Segment | Residential Construction | Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Balance of loans acquired			$ 0		$ 0
Allowance for loans acquired			$ 0		$ 0
Allowance to loans acquired with deteriorated credity quality ratio			0.00%		0.00%