INTEREST AND DIVIDEND ON INVESTMENTS- Components of interest and dividend income on investments (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of interest and dividend income on investments [Abstract]
Interest income on investment securities, money market investments, and interest-bearing cash accounts	$ 68,592	$ 53,634	$ 52,816
Dividends on FHLB stock	2,728	2,105	1,454
Total interest and dividends on investments	$ 71,320	$ 55,739	$ 54,270

The amount of interest income and other income recognized during the period. Included in this element is interest derived from investments in debt securities, cash and cash equivalents, and other investments which reflect the time value of money or transactions in which the payments are for the use or forbearance of money and other income from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business).

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration