Average reserve balances required to be maintained with federal reserve bank

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Collaborative Arrangement, Expense Reimbursement

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Delinquency period for loan charge offs.

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Discontinued period of principal or interest payment of contractual payment.

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Income Taxes Examination Likelihood Of Realization On Settlement Percentage

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Maximum loan to value ratio.

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New Accounting Pronouncement or Change in Accounting Principle, Phase-In Period

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Number of share based compensation plans.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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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.

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Nominal or face amount used to calculate payment on derivative.

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The number of derivative instruments of a particular group held by the entity.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amount of Federal Home Loan Bank (FHLB) and Federal Reserve Bank stock.

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Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Discount rate from fair value on purchase date that participants pay for shares.

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Purchase price of common stock expressed as a percentage of its fair value.

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Significant Accounting Policies and Basis of Presentation - Narrative (Detail) $ in Thousands		6 Months Ended	12 Months Ended
	Jan. 01, 2020	Dec. 31, 2016 Segment	Dec. 31, 2019 USD ($) CompensationPlan derivative Segment Swap	Dec. 31, 2018 USD ($) derivative Swap	Dec. 31, 2017 USD ($)	Dec. 31, 2014	Jan. 01, 2018 USD ($)
Derivative [Line Items]
Average reserve balances required to be maintained with federal reserve bank			$ 69,100	$ 58,400
Contractual payment of principal duration (days)			90 days
Contractual terms for loans (months)			6 months
Maximum loan to value ratio			80.00%
Delinquency period for loan charge-offs (days)			120 days
Goodwill and other intangibles			$ 15,195	16,499	$ 16,295
FHLB, Federal Reserve Bank, and other restricted stock			84,214	89,685
Federal Home Loan Bank stock			$ 60,800	67,300
Percentage of tax position that will be realized or sustained upon examination			50.00%
Number of share-based compensation plans \| CompensationPlan			4
Number of reportable segments (segment) \| Segment		2	2
Collaborative arrangement, expense reimbursement			$ 7,700	8,400	2,400
Increase to loans and leases receivable allowance			$ 56,379	$ 39,972	$ 38,015
Accounting Standards Update 2016-01
Derivative [Line Items]
Cumulative effect adjustment							$ 0
Interest rate swaps \| Not Designated as Hedging Instrument
Derivative [Line Items]
Number of interest rate swaps \| Swap			140	98
Derivative notional amount			$ 1,400,000	$ 1,000,000
Interest rate swaps \| Cash Flow Hedging \| Designated as Hedging Instrument
Derivative [Line Items]
Number of interest rate swaps \| derivative			4	6
Derivative notional amount			$ 725,000	$ 750,000
Credit contracts \| Not Designated as Hedging Instrument
Derivative [Line Items]
Derivative notional amount			$ 167,100	$ 94,900
ESPP
Derivative [Line Items]
Purchase price under employee stock purchase plan (percent)			85.00%			85.00%
Purchase price under employee stock purchase plan, discount (percent)			15.00%			15.00%
Retained Earnings \| Accounting Standards Update 2016-01
Derivative [Line Items]
Cumulative effect adjustment							1,041
Accumulated Other Comprehensive Income (Loss) \| Accounting Standards Update 2016-01
Derivative [Line Items]
Cumulative effect adjustment							$ (1,041)
Discounted cash flow \| Fair Value Estimate
Derivative [Line Items]
Interest-only GNMA securities			$ 16,272
Subsequent Event \| Accounting Standards Update 2016-13
Derivative [Line Items]
Phase-in period (years)	3 years