Regulatory Capital (Summary of Company's Capital Amounts And Ratios) (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital	$ 3,429,047	$ 3,347,926
Capital to Risk Weighted Assets	0.1426	0.1563
Capital Required for Capital Adequacy	$ 1,923,934	$ 1,713,891
Capital Required for Capital Adequacy to Risk Weighted Assets	0.0800	0.0800
Capital Required to be Well Capitalized	$ 2,404,917	$ 2,142,364
Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000
Tier One Risk Based Capital	$ 2,785,794	$ 2,636,194
Tier One Risk Based Capital to Risk Weighted Assets	0.1158	0.1231
Tier One Risk Based Capital Required for Capital Adequacy	$ 1,442,950	$ 1,285,418
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	0.0600	0.0600
Tier One Risk Based Capital Required to be Well Capitalized	$ 1,923,934	$ 1,713,891
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Common Equity Tier One Capital	$ 2,785,794	$ 2,636,194
Common Equity Tier One Capital Ratio	0.1158	0.1231
Common Equity Tier One Capital Required for Capital Adequacy	$ 1,082,213	$ 964,064
Tier One Common Equity Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Capital Required to be Well-Capitalized	$ 1,563,196	$ 1,392,536
Tier One Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier One Leverage Capital	$ 2,785,794	$ 2,636,194
Tier One Leverage Capital to Average Assets	0.0901	0.0898
Tier One Leverage Capital Required for Capital Adequacy	$ 1,236,265	$ 1,174,129
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	0.0400	0.0400
Tier One Leverage Capital Required to be Well Capitalized	$ 1,545,331	$ 1,467,661
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	0.0500	0.0500
Umpqua Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital	$ 3,085,848	$ 3,134,116
Capital to Risk Weighted Assets	0.1283	0.1463
Capital Required for Capital Adequacy	$ 1,924,015	$ 1,713,809
Capital Required for Capital Adequacy to Risk Weighted Assets	0.0800	0.0800
Capital Required to be Well Capitalized	$ 2,405,019	$ 2,142,262
Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000
Tier One Risk Based Capital	$ 2,893,593	$ 2,873,383
Tier One Risk Based Capital to Risk Weighted Assets	0.1203	0.1341
Tier One Risk Based Capital Required for Capital Adequacy	$ 1,443,011	$ 1,285,357
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	0.0600	0.0600
Tier One Risk Based Capital Required to be Well Capitalized	$ 1,924,015	$ 1,713,809
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Common Equity Tier One Capital	$ 2,893,593	$ 2,873,383
Common Equity Tier One Capital Ratio	0.1203	0.1341
Common Equity Tier One Capital Required for Capital Adequacy	$ 1,082,258	$ 964,018
Tier One Common Equity Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Capital Required to be Well-Capitalized	$ 1,563,262	$ 1,392,470
Tier One Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier One Leverage Capital	$ 2,893,593	$ 2,873,383
Tier One Leverage Capital to Average Assets	0.0936	0.0979
Tier One Leverage Capital Required for Capital Adequacy	$ 1,236,518	$ 1,174,065
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	0.0400	0.0400
Tier One Leverage Capital Required to be Well Capitalized	$ 1,545,648	$ 1,467,581
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	0.0500	0.0500