Cover Page - shares	9 Months Ended
	Sep. 30, 2023	Oct. 27, 2023
Entity Listings [Line Items]
Document Type	10-Q
Document Transition Report	false
Document Period End Date	Sep. 30, 2023
Entity File Number	001-36408
Entity Registrant Name	PACWEST BANCORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0885320
Entity Address, Address Line One	9701 Wilshire Blvd., Suite 700
Entity Address, City or Town	Beverly Hills
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90212
City Area Code	310
Local Phone Number	887-8500
Entity Current Reporting Status	No
Entity Central Index Key	0001102112
Entity Filer Category	Large Accelerated Filer
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		118,587,136
Common Stock
Entity Listings [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	PACW
Security Exchange Name	NASDAQ
Preferred Class A
Entity Listings [Line Items]
Title of 12(b) Security	perpetual preferred stock, Series A
Trading Symbol	PACWP
Security Exchange Name	NASDAQ