CREDIT QUALITY ASSESSMENT (Activity in Allowance for Loan and Lease Losses by Respective Loan Portfolio Segment) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				$ 40,895				$ 37,802	$ 40,895	$ 37,802	$ 38,766
Provision (credit)	$ 572	$ 781	$ 2,957	1,236	$ 1,850	$ 1,706	$ 1,218	597	5,546	5,371	(163)
Charge-offs									(3,134)	(3,795)	(2,687)
Recoveries									760	1,517	1,886
Net charge-offs									(2,374)	(2,278)	(801)
Balance at period end	44,067				40,895				44,067	40,895	37,802
Total loans and leases	$ 3,927,808				$ 3,495,370				$ 3,927,808	$ 3,495,370
Allowance for loans and leases to total loans and leases ratio	1.12%				1.17%				1.12%	1.17%
Balance of loans specifically evaluated for impairment	$ 24,092				$ 28,927				$ 24,092	$ 28,927
Allowance for loans specifically evaluated for impairment	$ 4,825				$ 3,375				$ 4,825	$ 3,375	2,894
Specific allowance to specific loans ratio	20.03%				11.67%				20.03%	11.67%
Balance of loans collectively evaluated	$ 3,903,716				$ 3,466,443				$ 3,903,716	$ 3,466,443
Allowance for loans collectively evaluated	39,242				37,520				$ 39,242	$ 37,520	34,908
Collective allowance to collective loans ratio									1.01%	1.08%
Commercial
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				6,529				5,852	$ 6,529	$ 5,852
Provision (credit)									1,563	508
Charge-offs									(597)	(306)
Recoveries									44	475
Net charge-offs									(553)	169
Balance at period end	7,539				6,529				7,539	6,529	5,852
Total loans and leases	$ 467,286				$ 465,765				$ 467,286	$ 465,765
Allowance for loans and leases to total loans and leases ratio	1.61%				1.40%				1.61%	1.40%
Balance of loans specifically evaluated for impairment	$ 7,018				$ 5,273				$ 7,018	$ 5,273
Allowance for loans specifically evaluated for impairment	$ 2,604				$ 1,318				$ 2,604	$ 1,318
Specific allowance to specific loans ratio	37.10%				25.00%				37.10%	25.00%
Balance of loans collectively evaluated	$ 460,268				$ 460,492				$ 460,268	$ 460,492
Allowance for loans collectively evaluated	4,935				5,211				$ 4,935	$ 5,211
Collective allowance to collective loans ratio									1.07%	1.13%
Leases
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				0				9	$ 0	$ 9
Provision (credit)										(5)
Charge-offs										(4)
Recoveries										0
Net charge-offs										(4)
Balance at period end					0					0	9
Total loans and leases					0					0
Consumer
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				3,456				3,592	3,456	3,592
Provision (credit)									112	619
Charge-offs									(888)	(998)
Recoveries									148	243
Net charge-offs									(740)	(755)
Balance at period end	2,828				3,456				2,828	3,456	3,592
Total loans and leases	$ 456,657				$ 450,875				$ 456,657	$ 450,875
Allowance for loans and leases to total loans and leases ratio	0.62%				0.77%				0.62%	0.77%
Balance of loans collectively evaluated	$ 456,657				$ 450,875				$ 456,657	$ 450,875
Allowance for loans collectively evaluated	2,828				3,456				$ 2,828	$ 3,456
Collective allowance to collective loans ratio									0.62%	0.77%
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				4,691				4,267	$ 4,691	$ 4,267
Provision (credit)									(31)	583
Charge-offs									(48)	(739)
Recoveries									40	580
Net charge-offs									(8)	(159)
Balance at period end	4,652				4,691				4,652	4,691	4,267
Total loans and leases	$ 308,279				$ 255,980				$ 308,279	$ 255,980
Allowance for loans and leases to total loans and leases ratio	1.51%				1.83%				1.51%	1.83%
Balance of loans specifically evaluated for impairment	$ 137				$ 194				$ 137	$ 194
Allowance for loans specifically evaluated for impairment	$ 0				$ 58				$ 0	$ 58
Specific allowance to specific loans ratio	0.00%				29.90%				0.00%	29.90%
Balance of loans collectively evaluated	$ 308,142				$ 255,786				$ 308,142	$ 255,786
Allowance for loans collectively evaluated	4,652				4,633				$ 4,652	$ 4,633
Collective allowance to collective loans ratio									1.51%	1.81%
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				10,440				9,784	$ 10,440	$ 9,784
Provision (credit)									2,563	727
Charge-offs									(197)	(91)
Recoveries									133	20
Net charge-offs									(64)	(71)
Balance at period end	12,939				10,440				12,939	10,440	9,784
Total loans and leases	$ 928,113				$ 719,084				$ 928,113	$ 719,084
Allowance for loans and leases to total loans and leases ratio	1.39%				1.45%				1.39%	1.45%
Balance of loans specifically evaluated for impairment	$ 8,107				$ 10,441				$ 8,107	$ 10,441
Allowance for loans specifically evaluated for impairment	$ 1,736				$ 1,489				$ 1,736	$ 1,489
Specific allowance to specific loans ratio	21.41%				14.26%				21.41%	14.26%
Balance of loans collectively evaluated	$ 920,006				$ 708,643				$ 920,006	$ 708,643
Allowance for loans collectively evaluated	11,203				8,951				$ 11,203	$ 8,951
Collective allowance to collective loans ratio									1.22%	1.26%
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				7,984				7,143	$ 7,984	$ 7,143
Provision (credit)									(104)	1,881
Charge-offs									0	(1,043)
Recoveries									5	3
Net charge-offs									5	(1,040)
Balance at period end	7,885				7,984				7,885	7,984	7,143
Total loans and leases	$ 775,552				$ 678,027				$ 775,552	$ 678,027
Allowance for loans and leases to total loans and leases ratio	1.02%				1.18%				1.02%	1.18%
Balance of loans specifically evaluated for impairment	$ 5,567				$ 6,580				$ 5,567	$ 6,580
Allowance for loans specifically evaluated for impairment	$ 485				$ 510				$ 485	$ 510
Specific allowance to specific loans ratio	8.71%				7.75%				8.71%	7.75%
Balance of loans collectively evaluated	$ 769,985				$ 671,447				$ 769,985	$ 671,447
Allowance for loans collectively evaluated	7,400				7,474				$ 7,400	$ 7,474
Collective allowance to collective loans ratio									0.96%	1.11%
Residential Real Estate Portfolio Segment | Residential Mortgage
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				6,901				6,232	$ 6,901	$ 6,232
Provision (credit)									1,406	1,138
Charge-offs									(1,404)	(614)
Recoveries									358	145
Net charge-offs									(1,046)	(469)
Balance at period end	7,261				6,901				7,261	6,901	6,232
Total loans and leases	$ 841,692				$ 796,358				$ 841,692	$ 796,358
Allowance for loans and leases to total loans and leases ratio	0.86%				0.87%				0.86%	0.87%
Balance of loans specifically evaluated for impairment	$ 3,263				$ 6,439				$ 3,263	$ 6,439
Allowance for loans specifically evaluated for impairment	0				0				0	0
Balance of loans collectively evaluated	838,429				789,919				838,429	789,919
Allowance for loans collectively evaluated	7,261				6,901				$ 7,261	$ 6,901
Collective allowance to collective loans ratio									0.87%	0.87%
Residential Real Estate Portfolio Segment | Residential Construction
Financing Receivable Allowance For Credit Losses [Line Items]
Balance at beginning of year				$ 894				$ 923	$ 894	$ 923
Provision (credit)									37	(80)
Charge-offs									0	0
Recoveries									32	51
Net charge-offs									32	51
Balance at period end	963				894				963	894	$ 923
Total loans and leases	$ 150,229				$ 129,281				$ 150,229	$ 129,281
Allowance for loans and leases to total loans and leases ratio	0.64%				0.69%				0.64%	0.69%
Balance of loans specifically evaluated for impairment	$ 0				$ 0				$ 0	$ 0
Allowance for loans specifically evaluated for impairment	0				0				0	0
Balance of loans collectively evaluated	150,229				129,281				150,229	129,281
Allowance for loans collectively evaluated	$ 963				$ 894				$ 963	$ 894
Collective allowance to collective loans ratio									0.64%	0.69%