ADVANCES FROM THE FEDERAL HOME LOAN BANK (FHLB) - Advances from FHLB Mature (Detail) $ in Thousands	Sep. 30, 2017 USD ($)
One to thirty days
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank Advances	$ 250,000
Over thrity days to ninety days
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank Advances	0
Over six months to one year
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank Advances	25,000
Over one to three years
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank Advances	320,000
Over three months to six months
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank Advances	0
Over Three to four years [Member]
Federal Home Loan Bank Advances Branch Of F H L B Bank [Line Items]
Federal Home Loan Bank Advances	$ 320,000