Junior and Other Subordinated Debentures (Junior Subordinated Debentures) (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 28, 2023	Dec. 31, 2023	Dec. 31, 2022
Junior Subordinated Debentures [Line Items]
Issued amount		$ 475,272
Carrying value, at fair value		316,440	$ 323,639
Carrying value, at amortized cost		107,895	$ 87,813
Carrying value		414,335
Junior Subordinated Debt, at Fair Value
Junior Subordinated Debentures [Line Items]
Issued amount		379,390
Carrying value, at fair value		316,440
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust II
Junior Subordinated Debentures [Line Items]
Issued amount		20,619
Carrying value, at fair value		$ 19,401
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.35%
Effective rate		9.57%
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust III
Junior Subordinated Debentures [Line Items]
Issued amount		$ 30,928
Carrying value, at fair value		$ 29,203
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.45%
Effective rate		9.63%
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust IV
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at fair value		$ 9,319
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		2.85%
Effective rate		9.41%
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust V
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at fair value		$ 9,146
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		2.85%
Effective rate		9.57%
Junior Subordinated Debt, at Fair Value | Umpqua Master Trust I
Junior Subordinated Debentures [Line Items]
Issued amount		$ 41,238
Carrying value, at fair value		$ 30,557
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		1.35%
Effective rate		9.44%
Junior Subordinated Debt, at Fair Value | Umpqua Master Trust IB
Junior Subordinated Debentures [Line Items]
Issued amount		$ 20,619
Carrying value, at fair value		$ 17,644
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		2.75%
Effective rate		9.81%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust III
Junior Subordinated Debentures [Line Items]
Issued amount		$ 14,433
Carrying value, at fair value		$ 13,506
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.25%
Effective rate		9.50%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust IV
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at fair value		$ 9,489
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.15%
Effective rate		9.55%
Junior Subordinated Debt, at Fair Value | Sterling Capital Statutory Trust V
Junior Subordinated Debentures [Line Items]
Issued amount		$ 20,619
Carrying value, at fair value		$ 18,955
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.25%
Effective rate		9.65%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust VI
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at fair value		$ 9,397
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.20%
Effective rate		9.71%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust VII
Junior Subordinated Debentures [Line Items]
Issued amount		$ 56,702
Carrying value, at fair value		$ 43,599
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		1.53%
Effective rate		9.33%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust VIII
Junior Subordinated Debentures [Line Items]
Issued amount		$ 51,547
Carrying value, at fair value		$ 39,773
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		1.63%
Effective rate		9.43%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust IX
Junior Subordinated Debentures [Line Items]
Issued amount		$ 46,392
Carrying value, at fair value		$ 35,166
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		1.40%
Effective rate		9.31%
Junior Subordinated Debt, at Fair Value | Lynnwood Financial Statutory Trust I
Junior Subordinated Debentures [Line Items]
Issued amount		$ 9,279
Carrying value, at fair value		$ 8,464
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.15%
Effective rate		9.62%
Junior Subordinated Debt, at Fair Value | Lynnwood Financial Statutory Trust II
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at fair value		$ 8,253
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		1.80%
Effective rate		9.30%
Junior Subordinated Debt, at Fair Value | Klamath First Capital Trust I
Junior Subordinated Debentures [Line Items]
Issued amount		$ 15,464
Carrying value, at fair value		$ 14,568
Variable rate basis		SOFR + 0.42826%
Basis spread on SOFR+0.26161%		3.75%
Effective rate		10.22%
Junior Subordinated Debt, at Amortized Cost
Junior Subordinated Debentures [Line Items]
Issued amount		$ 95,882
Carrying value, at amortized cost		97,895
Junior Subordinated Debt, at Amortized Cost | Humboldt Bancorp Statutory Trust II
Junior Subordinated Debentures [Line Items]
Issued amount		10,310
Carrying value, at amortized cost		$ 10,735
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.60%
Effective rate		8.37%
Junior Subordinated Debt, at Amortized Cost | Humboldt Bancorp Statutory Trust III
Junior Subordinated Debentures [Line Items]
Issued amount		$ 27,836
Carrying value, at amortized cost		$ 29,041
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		2.95%
Effective rate		7.79%
Junior Subordinated Debt, at Amortized Cost | CIB Capital Trust
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at amortized cost		$ 10,693
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.45%
Effective rate		8.35%
Junior Subordinated Debt, at Amortized Cost | Western Sierra Statutory Trust I
Junior Subordinated Debentures [Line Items]
Issued amount		$ 6,186
Carrying value, at amortized cost		$ 6,186
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.58%
Effective rate		9.22%
Junior Subordinated Debt, at Amortized Cost | Western Sierra Statutory Trust II
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at amortized cost		$ 10,310
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		3.60%
Effective rate		9.24%
Junior Subordinated Debt, at Amortized Cost | Western Sierra Statutory Trust III
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at amortized cost		$ 10,310
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		2.90%
Effective rate		8.56%
Junior Subordinated Debt, at Amortized Cost | Western Sierra Statutory Trust IV
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at amortized cost		$ 10,310
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		2.90%
Effective rate		8.56%
Junior Subordinated Debt, at Amortized Cost | Bank of Commerce Holdings Trust II
Junior Subordinated Debentures [Line Items]
Issued amount		$ 10,310
Carrying value, at amortized cost	$ 10,300	$ 10,310
Variable rate basis		SOFR + 0.26161%
Basis spread on SOFR+0.26161%		1.58%
Effective rate		7.23%
Other Subordinated Debt
Junior Subordinated Debentures [Line Items]
Carrying value, at amortized cost	$ 10,000
Basis spread on SOFR+0.26161%	5.26%