FHLB Advances - Summary of Federal Home Loan Bank Advances (Parenthetical) (Detail)	12 Months Ended
Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Advance structured note, payments due monthly, maturity	2030-02

Federal home loan bank fixed rate advances maturity date.

No definition available.

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