INVESTMENT SECURITIES - Proceeds from Sales and Calls of Securities and Associated Gross Gains and Losses (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Gross realized gains on sales and calls of securities available-for-sale	$ 2,011		$ 0	$ 2,011	$ 208
Gross realized losses on sales and calls of securities available-for-sale	0		0	0	0
Net realized gains on sales and calls of securities available-for-sale	2,011	$ 0	0	2,011	208
Proceeds from sales and calls of securities available-for-sale	$ 22,728		$ 298,156	$ 52,728	$ 820,048