Regulatory Capital (Summary Of Company's Capital Amounts And Ratios) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Consolidated [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital, Actual Amount	$ 1,357,206	$ 1,287,560
Total Capital, Actual Ratio	16.52%	17.16%
Total Capital, For Capital Adequacy purposes Amount	657,243	600,261
Total Capital, For Capital Adequacy purposes Ratio	8.00%	8.00%
Total Capital, To be Well Capitalized Amount	821,553	750,326
Total Capital, To be Well Capitalized Ratio	10.00%	10.00%
Tier I Capital , Actual Amount	1,254,514	1,193,740
Tier I Capital , Actual Ratio	15.27%	15.91%
Tier I Capital , For Capital Adequacy purposes Amount	328,622	300,123
Tier I Capital , For Capital Adequacy purposes Ratio	4.00%	4.00%
Tier I Capital , To be Well Capitalized Amount	492,933	450,185
Tier I Capital , To be Well Capitalized Ratio	6.00%	6.00%
Tier I Capital (to Average Assets) , Actual Amount	1,254,514	1,193,740
Tier I Capital (to Average Assets), Actual Ratio	11.44%	10.91%
Tier I Capital (to Average Assets), For Capital Adequacy purposes Amount	438,641	437,668
Tier I Capital (to Average Assets), For Capital Adequacy purposes Ratio	4.00%	4.00%
Tier I Capital (to Average Assets), To be Well Capitalized Amount	548,302	547,085
Tier I Capital (to Average Assets), To be Well Capitalized Ratio	5.00%	5.00%
Umpqua Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Total Capital, Actual Amount	1,234,010	1,163,611
Total Capital, Actual Ratio	15.03%	15.53%
Total Capital, For Capital Adequacy purposes Amount	656,825	599,413
Total Capital, For Capital Adequacy purposes Ratio	8.00%	8.00%
Total Capital, To be Well Capitalized Amount	821,031	749,267
Total Capital, To be Well Capitalized Ratio	10.00%	10.00%
Tier I Capital , Actual Amount	1,131,373	1,069,914
Tier I Capital , Actual Ratio	13.78%	14.28%
Tier I Capital , For Capital Adequacy purposes Amount	328,410	299,696
Tier I Capital , For Capital Adequacy purposes Ratio	4.00%	4.00%
Tier I Capital , To be Well Capitalized Amount	492,615	449,544
Tier I Capital , To be Well Capitalized Ratio	6.00%	6.00%
Tier I Capital (to Average Assets) , Actual Amount	1,131,373	1,069,914
Tier I Capital (to Average Assets), Actual Ratio	10.32%	9.78%
Tier I Capital (to Average Assets), For Capital Adequacy purposes Amount	438,517	437,593
Tier I Capital (to Average Assets), For Capital Adequacy purposes Ratio	4.00%	4.00%
Tier I Capital (to Average Assets), To be Well Capitalized Amount	$ 548,146	$ 546,991
Tier I Capital (to Average Assets), To be Well Capitalized Ratio	5.00%	5.00%