Maximum exercisable period for stock options.

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- Definition

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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No definition available.

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- Definition

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

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No definition available.

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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

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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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

Unrecognized cost of unvested share-based compensation awards.

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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- Definition

Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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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

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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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 an established share-based compensation plan.

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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

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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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 share-based compensation awards.

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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, 2018 USD ($) year shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum exercisable period for stock options (years)	10 years
Participant vested in an annual deferral accounts	100.00%
Involuntary termination age (year) \| year	65
Employee stock purchase plan expense \| $	$ 8,600	$ 6,100	$ 6,200
Nonvested awards, compensation cost not yet recognized \| $	20,400
Cash received from exercise of options \| $	$ 2,800
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)	37,377
Voting common stock issued \| $	$ 1,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of exercisable stock options (shares)	849,303
Award vesting period (years)	3 years
Number of shares granted (shares)	10,000
Options expiration date (years)	10 years
Tax benefit from exercise of options \| $	$ 700
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years
Number of units vested (shares)	97,414
Number of restricted stock units granted (shares)	433,614
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
2004 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares that may be issued under 2014 plan (shares)	2,750,000
Aggregate number of shares of common stock available for grant (shares)	1,311,743
2004 Plan \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (shares)	416,241
BRRP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units outstanding (shares)	254,976
BRRP \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (shares)	17,373
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 \| $	$ 141	$ 132	$ 103
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%
Cliff \| 2004 Plan \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units granted (shares)	31,257
Cliff \| BRRP \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	5 years
Waterfall \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (years)	3 years