Regulatory Capital (Summary of Company's Capital Amounts And Ratios) (Details) $ in Thousands	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Consolidated
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital	$ 3,651,382	$ 3,429,047
Capital to Risk Weighted Assets	0.1371	0.1426
Capital Required for Capital Adequacy	$ 2,130,565	$ 1,923,934
Capital Required for Capital Adequacy to Risk Weighted Assets	0.0800	0.0800
Capital Required to be Well Capitalized	$ 2,663,207	$ 2,404,917
Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000
Tier One Risk Based Capital	$ 2,934,708	$ 2,785,794
Tier One Risk Based Capital to Risk Weighted Assets	0.1102	0.1158
Tier One Risk Based Capital Required for Capital Adequacy	$ 1,597,924	$ 1,442,950
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	$ 2,130,565	$ 1,923,934
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Common Equity Tier One Capital	$ 2,934,708	$ 2,785,794
Common Equity Tier One Capital Ratio	0.1102	0.1158
Common Equity Tier One Capital Required for Capital Adequacy	$ 1,198,443	$ 1,082,213
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	$ 1,731,084	$ 1,563,196
Tier One Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier One Leverage Capital	$ 2,934,708	$ 2,785,794
Tier One Leverage Capital to Average Assets	0.0914	0.0901
Tier One Leverage Capital Required for Capital Adequacy	$ 1,283,669	$ 1,236,265
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	0.0400	0.0400
Tier One Leverage Capital Required to be Well Capitalized	$ 1,604,586	$ 1,545,331
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	$ 3,440,574	$ 3,085,848
Capital to Risk Weighted Assets	0.1292	0.1283
Capital Required for Capital Adequacy	$ 2,130,240	$ 1,924,015
Capital Required for Capital Adequacy to Risk Weighted Assets	0.0800	0.0800
Capital Required to be Well Capitalized	$ 2,662,799	$ 2,405,019
Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000
Tier One Risk Based Capital	$ 3,174,899	$ 2,893,593
Tier One Risk Based Capital to Risk Weighted Assets	0.1192	0.1203
Tier One Risk Based Capital Required for Capital Adequacy	$ 1,597,680	$ 1,443,011
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	$ 2,130,240	$ 1,924,015
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Common Equity Tier One Capital	$ 3,174,899	$ 2,893,593
Common Equity Tier One Capital Ratio	0.1192	0.1203
Common Equity Tier One Capital Required for Capital Adequacy	$ 1,198,260	$ 1,082,258
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	$ 1,730,820	$ 1,563,262
Tier One Common Equity Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Tier One Leverage Capital	$ 3,174,899	$ 2,893,593
Tier One Leverage Capital to Average Assets	0.0989	0.0936
Tier One Leverage Capital Required for Capital Adequacy	$ 1,283,610	$ 1,236,518
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	0.0400	0.0400
Tier One Leverage Capital Required to be Well Capitalized	$ 1,604,513	$ 1,545,648
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	0.0500	0.0500