Maximum exercisable period for stock options.

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Restricted Stock Units, Percentage Granted as Long Term Incentive Compensation

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Restricted Stock Units, Percentage Vesting Upon Meeting Certain Thresholds

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- Definition

Share based compensation arrangement by share based payment award number of underlying shares available.

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No definition available.

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- Definition

Share based compensation arrangement by share based payment award percentage by which tangible book value must increase.

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- Definition

Share based compensation arrangement by share based payment award receipt deferral percentage.

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- Definition

Share-based compensation arrangement by share based payment involuntary termination age.

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- Definition

Share-based compensation arrangement by share based payment participant vested in annual deferral accounts.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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-Name Accounting Standards Codification
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- Definition

The total fair value of shares issued during the period under a deferred compensation arrangement.

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- Definition

Number of shares issued pursuant to the terms of a deferred compensation arrangement.

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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- Definition

Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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- Definition

Amount of cash inflow from exercise of option under share-based payment arrangement.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

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

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

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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No definition available.

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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

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No definition available.

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- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Gross number of share options (or share units) granted during the period.

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No definition available.

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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

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No definition available.

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Share-Based Compensation Plans - Narrative (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) year shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum exercisable period for stock options (years)	10 years
Aggregate number of shares of common stock available for grant (shares)	1,719,901
Employee stock purchase plan expense \| $	$ 12,000	$ 8,900	$ 8,600
Nonvested awards, compensation cost not yet recognized \| $	20,400
Cash received from exercise of options \| $	100
Tax benefit from exercise of options \| $	$ 14
Restricted stock units, granted as long term incentive compensation (percent)	40.00%
Restricted stock units, vesting upon meeting certain thresholds (percent)	60.00%
Director \| Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Voting common stock issued (shares)	41,136
Voting common stock issued \| $	$ 500
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Options expiration date (years)	10 years
Number of shares granted (shares)	0
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Number of restricted stock units granted (shares)	903,581
Restricted stock units vesting percentage per year	33.33%
Minimum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Maximum \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	5 years
2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fully diluted tangible book value	50.00%
Maximum number of shares that may be issued under 2010 plan (shares)	3,666,667
2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued under plan (shares)	1,500,000
2004 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued under plan (shares)	2,750,000
BRRP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Participant vested in an annual deferral accounts		100.00%
Involuntary termination age (year) \| year	65
Restricted stock units outstanding (shares)	110,571
BRRP \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Receipt deferral percentage under BRRP plan		25.00%
BRRP \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Receipt deferral percentage under BRRP plan		50.00%
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee stock purchase plan expense \| $	$ 140	$ 170	$ 141
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%
2004 and 2019 Plan \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (shares)	903,581
Cliff \| 2004 and 2019 Plan \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Number of restricted stock units granted (shares)	440,446
Waterfall \| 2004 and 2019 Plan \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years