Ownership of Combined Company (Details) - USD ($) shares in Thousands	Dec. 31, 2023	Nov. 30, 2023
Pacific Western Bank
Business Acquisition [Line Items]
Share Price	$ 7.54
Shares, Outstanding		120,000
Pacific Western Bank | Pro Forma
Business Acquisition [Line Items]
Shares, Outstanding		77,906
Fair Market Value of Common Stock Outstanding		$ 900,593,000
Percentage of common stock outstanding		57.70%
Banc of California
Business Acquisition [Line Items]
Shares, Outstanding		57,000
Banc of California | Pro Forma
Business Acquisition [Line Items]
Shares, Outstanding		57,158
Fair Market Value of Common Stock Outstanding		$ 660,746,000
Percentage of common stock outstanding		42.30%
BANC
Business Acquisition [Line Items]
Share Price	$ 11.56
BANC | Pro Forma
Business Acquisition [Line Items]
Shares, Outstanding		135,064
Fair Market Value of Common Stock Outstanding		$ 1,561,339,000
Percentage of common stock outstanding		100.00%