Deposits - Additional Information (Detail) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Investments [Line Items]
Aggregate amounts of deposits reclassified as loan balances	$ 2.8	$ 3.1
Brokered deposits	$ 4,000.0	$ 4,000.0
Brokered deposits, weighted average interest rates	2.50%	1.37%
Money Market
Schedule of Investments [Line Items]
Brokered deposits	$ 1,900.0	$ 2,600.0
Interest Bearing Checking Accounts
Schedule of Investments [Line Items]
Brokered deposits	786.1	793.7
Certificates of Deposits
Schedule of Investments [Line Items]
Brokered deposits	$ 1,300.0	$ 567.8

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=50488274&loc=d3e64164-112818

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- Definition

Amount of interest-bearing domestic third-party deposits placed by or through the assistance of a deposit broker, also known as brokered deposit liabilities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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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.

+ References

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- Definition

The weighted average interest rate for domestic brokered deposit liabilities.

+ References

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