FINANCIAL INSTRUMENTS WITH OFF-BALANCE SHEET RISK AND DERIVATIVES (Summary Of Financial Instruments With Off-Balance Sheet Credit Risk) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Disclosure Summary Of Financial Instruments With Off Balance Sheet Credit Risk [Line Items]
Total Commitments to extend credit and available credit lines	$ 1,647,521	$ 1,473,733
Commercial
Disclosure Summary Of Financial Instruments With Off Balance Sheet Credit Risk [Line Items]
Total Commitments to extend credit and available credit lines	390,646	334,552
Real estate-development and construction
Disclosure Summary Of Financial Instruments With Off Balance Sheet Credit Risk [Line Items]
Total Commitments to extend credit and available credit lines	130,751	97,524
Real estate-residential mortgage
Disclosure Summary Of Financial Instruments With Off Balance Sheet Credit Risk [Line Items]
Total Commitments to extend credit and available credit lines	18,238	22,970
Lines of credit, principally home equity and business lines
Disclosure Summary Of Financial Instruments With Off Balance Sheet Credit Risk [Line Items]
Total Commitments to extend credit and available credit lines	1,044,949	949,939
Standby letters of credit
Disclosure Summary Of Financial Instruments With Off Balance Sheet Credit Risk [Line Items]
Total Commitments to extend credit and available credit lines	$ 62,937	$ 68,748