Junior Subordinated Debentures (Junior Subordinated Debentures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Junior Subordinated Debentures [Line Items]
Issued amount	$ 464,962
Carrying value, at fair value	293,081	$ 255,217
Carrying value, at amortized cost	88,041	$ 88,268
Carrying value	381,122
Junior Subordinated Debt, at Fair Value
Junior Subordinated Debentures [Line Items]
Issued amount	379,390
Carrying value, at fair value	293,081
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust II
Junior Subordinated Debentures [Line Items]
Issued amount	20,619
Carrying value, at fair value	$ 18,454
Variable rate basis	LIBOR
Basis spread on LIBOR	3.35%
Effective rate	3.89%
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust III
Junior Subordinated Debentures [Line Items]
Issued amount	$ 30,928
Carrying value, at fair value	$ 27,925
Variable rate basis	LIBOR
Basis spread on LIBOR	3.45%
Effective rate	3.99%
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust IV
Junior Subordinated Debentures [Line Items]
Issued amount	$ 10,310
Carrying value, at fair value	$ 8,726
Variable rate basis	LIBOR
Basis spread on LIBOR	2.85%
Effective rate	3.51%
Junior Subordinated Debt, at Fair Value | Umpqua Statutory Trust V
Junior Subordinated Debentures [Line Items]
Issued amount	$ 10,310
Carrying value, at fair value	$ 8,646
Variable rate basis	LIBOR
Basis spread on LIBOR	2.85%
Effective rate	3.66%
Junior Subordinated Debt, at Fair Value | Umpqua Master Trust I
Junior Subordinated Debentures [Line Items]
Issued amount	$ 41,238
Carrying value, at fair value	$ 27,270
Variable rate basis	LIBOR
Basis spread on LIBOR	1.35%
Effective rate	2.35%
Junior Subordinated Debt, at Fair Value | Umpqua Master Trust IB
Junior Subordinated Debentures [Line Items]
Issued amount	$ 20,619
Carrying value, at fair value	$ 16,475
Variable rate basis	LIBOR
Basis spread on LIBOR	2.75%
Effective rate	3.70%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust III
Junior Subordinated Debentures [Line Items]
Issued amount	$ 14,433
Carrying value, at fair value	$ 12,791
Variable rate basis	LIBOR
Basis spread on LIBOR	3.25%
Effective rate	3.82%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust IV
Junior Subordinated Debentures [Line Items]
Issued amount	$ 10,310
Carrying value, at fair value	$ 9,009
Variable rate basis	LIBOR
Basis spread on LIBOR	3.15%
Effective rate	3.78%
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	$ 18,115
Variable rate basis	LIBOR
Basis spread on LIBOR	3.25%
Effective rate	3.95%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust VI
Junior Subordinated Debentures [Line Items]
Issued amount	$ 10,310
Carrying value, at fair value	$ 8,972
Variable rate basis	LIBOR
Basis spread on LIBOR	3.20%
Effective rate	3.91%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust VII
Junior Subordinated Debentures [Line Items]
Issued amount	$ 56,702
Carrying value, at fair value	$ 39,396
Variable rate basis	LIBOR
Basis spread on LIBOR	1.53%
Effective rate	2.49%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust VIII
Junior Subordinated Debentures [Line Items]
Issued amount	$ 51,547
Carrying value, at fair value	$ 35,982
Variable rate basis	LIBOR
Basis spread on LIBOR	1.63%
Effective rate	2.63%
Junior Subordinated Debt, at Fair Value | Sterling Capital Trust IX
Junior Subordinated Debentures [Line Items]
Issued amount	$ 46,392
Carrying value, at fair value	$ 31,060
Variable rate basis	LIBOR
Basis spread on LIBOR	1.40%
Effective rate	2.29%
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	$ 8,080
Variable rate basis	LIBOR
Basis spread on LIBOR	3.15%
Effective rate	3.87%
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	$ 7,554
Variable rate basis	LIBOR
Basis spread on LIBOR	1.80%
Effective rate	2.73%
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	$ 14,626
Variable rate basis	LIBOR
Basis spread on LIBOR	3.75%
Effective rate	4.13%
Junior Subordinated Debt, at Amortized Cost
Junior Subordinated Debentures [Line Items]
Issued amount	$ 85,572
Carrying value, at amortized cost	88,041
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	$ 10,842
Variable rate basis	LIBOR
Basis spread on LIBOR	3.60%
Effective rate	3.13%
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	$ 29,302
Variable rate basis	LIBOR
Basis spread on LIBOR	2.95%
Effective rate	2.56%
Junior Subordinated Debt, at Amortized Cost | CIB Capital Trust
Junior Subordinated Debentures [Line Items]
Issued amount	$ 10,310
Carrying value, at amortized cost	$ 10,781
Variable rate basis	LIBOR
Basis spread on LIBOR	3.45%
Effective rate	3.04%
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	LIBOR
Basis spread on LIBOR	3.58%
Effective rate	3.71%
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	LIBOR
Basis spread on LIBOR	3.60%
Effective rate	3.81%
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	LIBOR
Basis spread on LIBOR	2.90%
Effective rate	3.02%
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	LIBOR
Basis spread on LIBOR	2.90%
Effective rate	3.02%