Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Number of investment positions in available-for-sale investments in a continuous unrealized loss position for less than one year or normal operating cycle, if longer, for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

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Sum of the carrying amounts as of the date of the latest financial statement presented of securities which are owned but transferred to another party to serve as collateral to partially or fully secure a debt obligation, repurchase agreement or other current or potential obligation, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

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Investment Securities - Narrative (Detail) $ in Thousands	12 Months Ended
Investment Securities - Narrative (Detail) $ in Thousands	Dec. 31, 2018 USD ($) Security	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2018 USD ($)
Debt Securities, Available-for-sale [Line Items]
Number of available-for-sale investment securities in the less than twelve month category (security) \| Security	26
Number of available-for-sale investment securities in the twelve month or more category (security) \| Security	0
Available-for-sale Securities		$ 471,371
Unrealized gains (losses) on available-for-sale securities	$ (20,283)	2,520	$ 2,505
Deferred tax liabilities, equity investments		0
Equity investment securities, at fair value	1,718
Pledged investment securities fair value	23,000	16,900
Equity securities
Debt Securities, Available-for-sale [Line Items]
Impairment loss		(12,900)
Available-for-sale Securities		3,352
Unrealized gains (losses) on available-for-sale securities		$ 1,000
Accounting Standards Update 2016-01
Debt Securities, Available-for-sale [Line Items]
Cumulative effect adjustment	0
Accounting Standards Update 2016-01 \| Accumulated Other Comprehensive Income (Loss)
Debt Securities, Available-for-sale [Line Items]
Cumulative effect adjustment				$ 1,000
Other Non-interest Income \| Equity securities
Debt Securities, Available-for-sale [Line Items]
Unrealized loss	$ 1,600