Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands			12 Months Ended
		Nov. 30, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Earnings Per Share [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic			$ 87,100	$ (1,938,925)	$ 404,274
Weighted Average Number of Shares Issued, Basic			168,921,000	86,563,000	78,875,000
Weighted Average Number of Shares, Restricted Stock			(480,000)	(1,169,407)	(1,604,412)
Weighted Average Number of Shares Outstanding, Basic, Total			168,441,000	85,394,000	77,271,000
Basic income per share (usd per share)			$ 0.52	$ (22.71)	$ 5.14
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 87,100	$ (1,938,925)	$ 396,800
Diluted income per share (usd per share)			$ 0.52	$ (22.71)	$ 5.14
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic			$ 87,100	$ (1,938,925)	$ 404,274
Allocated to Common and Equivalent Shares	[1]				(7,474)
Undistributed Earnings, Basic			$ 87,158	$ (1,938,925)	$ 396,800
Weighted Average Number of Shares Issued, Basic			168,921,000	86,563,000	78,875,000
Weighted Average Number of Shares, Restricted Stock			480,000	1,169,407	1,604,412
Weighted Average Number of Shares Outstanding, Basic			168,441,000	85,394,000	77,271,000
Basic income per share (usd per share)			$ 0.52	$ (22.71)	$ 5.14
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 87,100	$ (1,938,925)	$ 396,800
Weighted Average Number of Shares Outstanding, Diluted			168,684,000	85,394,000	77,271,000
Earnings Per Share, Diluted			$ 0.52	$ (22.71)	$ 5.14
Pacific Western Bank
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Stock Issued During Period, Shares, Acquisitions		0.6569
Common Stock
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Allocated to Common and Equivalent Shares				$ 0
Voting Common Stock | Common Stock
Earnings Per Share [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic			$ 81,619	$ (1,917,121)
Weighted Average Number of Shares Issued, Basic			158,321,000	85,603,000
Weighted Average Number of Shares, Restricted Stock			480,000	(1,169,000)
Weighted Average Number of Shares Outstanding, Basic, Total			157,841,000	84,434,000
Basic income per share (usd per share)			$ 0.52	$ (22.71)
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 81,619	$ (1,917,121)
Diluted income per share (usd per share)			$ 0.52	$ (22.71)
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic			$ 81,619	$ (1,917,121)
Allocated to Common and Equivalent Shares				0
Undistributed Earnings, Basic			$ 81,677	$ (1,917,121)
Weighted Average Number of Shares Issued, Basic			158,321,000	85,603,000
Weighted Average Number of Shares, Restricted Stock			(480,000)	1,169,000
Weighted Average Number of Shares Outstanding, Basic			157,841,000	84,434,000
Basic income per share (usd per share)			$ 0.52	$ (22.71)
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 81,619	$ (1,917,121)
Weighted Average Number of Shares Outstanding, Diluted			158,084,000	84,434,000
Earnings Per Share, Diluted			$ 0.52	$ (22.71)
Nonvoting Common Stock | Common Stock
Earnings Per Share [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic			$ 5,235	$ (20,884)
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic			5,235	(20,884)
Allocated to Common and Equivalent Shares				0
Undistributed Earnings, Basic			5,235	(20,884)
Class B Non-Voting | Common Stock
Earnings Per Share [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic			$ 246	$ (920)
Weighted Average Number of Shares Issued, Basic			477,000	40,000
Weighted Average Number of Shares, Restricted Stock			0	0
Weighted Average Number of Shares Outstanding, Basic, Total			477,000	40,000
Basic income per share (usd per share)			$ 0.52	$ 22.71
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 246	$ (920)
Diluted income per share (usd per share)			$ 0.52	$ 22.71
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net Income (Loss) Available to Common Stockholders, Basic			$ 246	$ (920)
Allocated to Common and Equivalent Shares				0
Undistributed Earnings, Basic			$ 246	$ (920)
Weighted Average Number of Shares Issued, Basic			477,000	40,000
Weighted Average Number of Shares, Restricted Stock			0	0
Weighted Average Number of Shares Outstanding, Basic			477,000	40,000
Basic income per share (usd per share)			$ 0.52	$ 22.71
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 246	$ (920)
Weighted Average Number of Shares Outstanding, Diluted			477,000	40,000
Earnings Per Share, Diluted			$ 0.52	$ 22.71
Non-Voting Common Stock Equivalents | Common Stock
Earnings Per Share [Abstract]
Weighted Average Number of Shares Issued, Basic			10,123,000	920,000
Weighted Average Number of Shares, Restricted Stock			0	0
Weighted Average Number of Shares Outstanding, Basic, Total			10,123,000	920,000
Basic income per share (usd per share)			$ 0.52	$ 22.71
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 5,235	$ (20,884)
Diluted income per share (usd per share)			$ 0.52	$ 22.71
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted Average Number of Shares Issued, Basic			10,123,000	920,000
Weighted Average Number of Shares, Restricted Stock			0	0
Weighted Average Number of Shares Outstanding, Basic			10,123,000	920,000
Basic income per share (usd per share)			$ 0.52	$ 22.71
Net Income Loss From Continuing Operation Available To Common Stockholders Basic			$ 5,235	$ (20,884)
Weighted Average Number of Shares Outstanding, Diluted			10,123,000	920,000
Earnings Per Share, Diluted			$ 0.52	$ 22.71

[1] (2) Represents cash dividends paid to holders of unvested restricted stock, net of forfeitures, plus undistributed earnings available to holders of unvested restricted stock, if any. (3) Diluted earnings per share is using the treasury method.