SECURITIES SOLD UNDER AGREEMENTS TO REPURCHASE - Repurchase Agreements Grouped by Counterparty (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Repurchase Agreement Counterparty [Line Items]
Securities Sold Under Agreements To Repurchase	$ 100,000	$ 150,086
JP Morgan Chase [Member]
Repurchase Agreement Counterparty [Line Items]
Securities Sold Under Agreements To Repurchase	$ 100,000
Weighted-Average Maturity	34 months

Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

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Name:	us-gaap_SecuritiesSoldUnderAgreementsToRepurchase
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant