Deposits - Summary of Certificates of Deposit with Balances of $250,000 or More by Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Contractual Maturities Of Time Deposits250000 Or More Disclosures [Abstract]
Three months or less	$ 12,670	$ 1,552
Over three months to six months	7,255	10,346
Over six months to twelve months	19,105	35,234
Over twelve months	18,306	14,151
Total	$ 57,336	$ 61,283

Contractual maturities of time deposits 250000 or more disclosures.

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Contractual maturities time deposits 250000 or more after twelve months.

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Contractual maturities time deposits 250000 or more six months through twelve months.

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Contractual maturities time deposits 250000 or more three months or less.

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Contractual maturities time deposits 250000 or more three months through six months.

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Time deposits 250000 or more.

No definition available.