Noninterest Income - Credit Card Fees (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gains and Losses on Derivatives [Abstract]
Credit card fees	$ 18,137	$ 14,033	$ 35,697	$ 28,003
Merchant service fees	3,425	2,883	6,331	5,623
Card service fees	1,364	1,183	2,590	2,203
Total credit card fees	$ 22,926	$ 18,099	$ 44,618	$ 35,829

Gains and Losses on Derivatives [Abstract]

No definition available.

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- Definition

Amount of income earned from credit card services (including late, over limit, and annual fees) and debit card services (including interchange fees, annual fees and other fees). Excludes interest income earned on credit card balances and transactions.

+ References

No definition available.

+ Details

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- Definition

Income earned from credit card services including late, over limit, and annual fees. This item excludes interest income earned on credit card balances and transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13 (d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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- Definition

Amount of income earned from debit card services, including interchange fees, annual fees and other fees.

+ References

No definition available.

+ Details

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- Definition

Amount of earnings on fees charged to merchants for the cardholder's use of a credit card. Excludes interest income earned on credit card balances, transactions and credit card services including late, over limit, and annual fees.

+ References

No definition available.

+ Details

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