LOANS AND LEASES - Commercial Real Estate Loans (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Commercial construction, acquisition and development loans	$ 1,146,612	$ 1,170,175
Credit Concentration Risk [Member] | Commercial Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	5.30%	5.60%
Loan Portfolio Diversification Risk [Member] | Commercial Real Estate Loans [Member] | Owner-Occupied [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	34.70%	35.30%
Loan Portfolio Diversification Risk [Member] | Commercial Real Estate Loans [Member] | Non-Owner-Occupied [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	65.30%	64.70%