Parent Company Financial Statements (Schedule Of Condensed Balance Sheets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Other assets	$ 232,411	$ 111,958
Total assets	22,613,274	11,636,112	11,795,443
Other liabilities	269,592	125,477
Junior subordinated debentures, at fair value	249,294	87,274
Junior subordinated debentures, at amortized cost	101,576	101,899
Total liabilities	18,832,277	9,908,686
Shareholders' equity	3,780,997	1,727,426
Total liabilities and shareholders' equity	22,613,274	11,636,112
Umpqua Bank [Member]
Condensed Financial Statements, Captions [Line Items]
Non-interest bearing deposits with subsidiary banks	102,102	72,679
Investments in Bank subsidiary	4,054,288	1,847,168
Investments In Nonbank subsidiaries	38,776	29,193
Other assets	4,079	1,590
Total assets	4,199,245	1,950,630
Payable to bank subsidiary	33	93
Other liabilities	67,345	33,938
Junior subordinated debentures, at fair value	249,294	87,274
Junior subordinated debentures, at amortized cost	101,576	101,899
Total liabilities	418,248	223,204
Shareholders' equity	3,780,997	1,727,426
Total liabilities and shareholders' equity	$ 4,199,245	$ 1,950,630