Revenue From Contracts With Customers - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Mar. 31, 2023	Sep. 30, 2023
Statement of Financial Position [Abstract]
Receivables, which are included in "Other assets"	$ 1,403	$ 1,477
Contract liabilities, which are included in "Accrued interest payable and other liabilities"	$ 488	$ 435

Contract With Customer, Liabilities Reclassified to Other Assets

No definition available.

Name:	pacw_ContractWithCustomerLiabilitiesReclassifiedtoOtherAssets
Namespace Prefix:	pacw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration