Share-based Compensation Arrangement by Share-based Payment Award, Performance Period

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- Definition

Vesting period of time-based restricted stock, higher limit

+ References

No definition available.

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- Definition

Vesting period of time-based restricted stock, lower limit

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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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.

+ References

No definition available.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Percentage of vesting of share-based compensation awards.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Stock Based Compensation (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares (shares)	1,383,914				1,436,120
Vesting period of time-based restricted stock, lower limit		3 years
Vesting period of time-based restricted stock, higher limit		4 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance vesting percentage	0.00%
Performance Target 1 \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance vesting percentage	150.00%
Performance Target 2 \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance vesting percentage	200.00%
Restricted Stock \| Vesting Based On Service
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated share-based compensation expense		$ 7.2	$ 5.4	$ 6.5
Restricted Stock Awards And Performance Based Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized share based compensation expense	$ 52.1
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares (shares)	325,741
Performance period	3 years
PacWest 2003 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares)	4,000,000
Number of shares available for grant (shares)	3,537,972
PacWest 2003 Stock Incentive Plan \| Time-Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested restricted shares (shares)	1,383,914