Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 29, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	PACWEST BANCORP
Entity Central Index Key	0001102112
Document Period End Date	Mar. 31, 2015
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		101,855,519
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes