EQUITY SECURITIES - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Summary of Investment Holdings [Line Items]
Capital stock par value	$ 100
Book value of investment in FHLB stock	$ 41,900		$ 41,900
Other non-interest income	8,950	$ 7,860
Equity Securities without Readily Determinable Fair Value, Amount	44,438		44,530
Equity Securities [Member]
Summary of Investment Holdings [Line Items]
Equity Securities, FV-NI			400
Other non-interest income	5	(7)
Equity Securities without Readily Determinable Fair Value, Amount	2,100		$ 2,200
Investment in Federal Home Loan Bank Stock [Member]
Summary of Investment Holdings [Line Items]
Dividend income from FHLB stock	$ 700	$ 700