RESIDENTIAL MORTGAGE LOANS - Additional Information (Details)	Dec. 31, 2017	Dec. 31, 2016
Residential Mortgage
Mortgage Loans on Real Estate [Line Items]
Percent of adjustable-rate loans	78.00%	85.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration