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Vesting period of time-based restricted stock, lower limit

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- Definition

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

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Amount of expense for employee benefit and equity-based compensation.

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

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

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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).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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

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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 weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Stock-Based Compensation Stock-Based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense, Tax Benefit	$ 3,900	$ 6,600	$ 6,000
Vesting period of time-based restricted stock, lower limit	3 years
Vesting period of time-based restricted stock, higher limit	4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	$ 14,000	$ 26,400	$ 26,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 48.15	$ 57.32
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 600	$ 2,200	$ 800
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	119,017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 10.29
Restricted Stock-Based Compensation
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Benefits and Share-based Compensation	$ 1,305	845	859
Restricted Stock [Member] \| Vesting Based On Service [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	27,400	$ 33,900	$ 31,400
Restricted Stock Awards And Performance Based Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount	$ 27,400
Time-Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	135,867
Equity Instruments Other than Options, Nonvested, Number	861,403	1,580,421
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 41.49
PRSU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted	134,751
Equity Instruments Other than Options, Nonvested, Number	0	382,504
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 48.41	$ 57.78	$ 49.00
PacWest 2003 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	8,769,328
PacWest 2003 Stock Incentive Plan [Member] \| Time-Based Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity Instruments Other than Options, Nonvested, Number	501,050
PacWest 2017 Total Amended and Restated Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	8,789,197