CREDIT QUALITY ASSESSMENT (Credit Risk Rating Indicators for Each Segment of Commercial Loan Portfolio) (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 4,194,118	$ 3,927,808
Commercial
Financing Receivable Recorded Investment [Line Items]
Total loans	451,667	467,286
Commercial Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Total loans	2,683,019	2,479,230
Commercial Portfolio Segment [Member] | Commercial
Financing Receivable Recorded Investment [Line Items]
Total loans	451,667	467,286
Commercial Portfolio Segment [Member] | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Total loans	295,222	308,279
Commercial Portfolio Segment [Member] | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	1,104,669	928,113
Commercial Portfolio Segment [Member] | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	831,461	775,552
Commercial Portfolio Segment [Member] | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans	2,644,464	2,426,773
Commercial Portfolio Segment [Member] | Pass | Commercial
Financing Receivable Recorded Investment [Line Items]
Total loans	435,183	442,725
Commercial Portfolio Segment [Member] | Pass | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Total loans	295,085	308,142
Commercial Portfolio Segment [Member] | Pass | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	1,096,591	917,255
Commercial Portfolio Segment [Member] | Pass | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	817,605	758,651
Commercial Portfolio Segment [Member] | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans	9,923	21,660
Commercial Portfolio Segment [Member] | Special Mention | Commercial
Financing Receivable Recorded Investment [Line Items]
Total loans	1,929	10,010
Commercial Portfolio Segment [Member] | Special Mention | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment [Member] | Special Mention | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	2,342	2,395
Commercial Portfolio Segment [Member] | Special Mention | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	5,652	9,255
Commercial Portfolio Segment [Member] | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans	28,632	30,797
Commercial Portfolio Segment [Member] | Substandard | Commercial
Financing Receivable Recorded Investment [Line Items]
Total loans	14,555	14,551
Commercial Portfolio Segment [Member] | Substandard | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Total loans	137	137
Commercial Portfolio Segment [Member] | Substandard | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	5,736	8,463
Commercial Portfolio Segment [Member] | Substandard | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	8,204	7,646
Commercial Portfolio Segment [Member] | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment [Member] | Doubtful | Commercial
Financing Receivable Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment [Member] | Doubtful | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment [Member] | Doubtful | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	0	0
Commercial Portfolio Segment [Member] | Doubtful | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	0	0
Commercial Real Estate Portfolio Segment | Commercial Acquisition, Development and Construction
Financing Receivable Recorded Investment [Line Items]
Total loans	295,222	308,279
Commercial Real Estate Portfolio Segment | Commercial Investor Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	1,104,669	928,113
Commercial Real Estate Portfolio Segment | Commercial Owner Occupied Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans	$ 831,461	$ 775,552