LOANS AND LEASES - Commercial Real Estate Loans (Detail) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Loans and Leases Receivable Disclosure [Line Items]
Commercial construction, acquisition and development loans	$ 1,272	$ 1,152
Credit Concentration Risk [Member] | Commercial Construction Loans [Member]
Loans and Leases Receivable Disclosure [Line Items]
Percent of total loans and leases	5.50%	5.20%
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	31.00%	35.10%
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	69.00%	64.90%