Parent Company Financial Statements (Schedule Of Condensed Statements Of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net income	$ 147,520us-gaap_ProfitLoss	$ 98,361us-gaap_ProfitLoss	$ 101,891us-gaap_ProfitLoss
Depreciation, amortization and accretion	33,873	18,267	16,040
Change in fair value of junior subordinated debentures	5,849	2,193	2,175
Net (increase) decrease in other assets	(45,874)	32,129	5,401
Net increase (decrease) in other liabilities	38,632	(7,589)	22,255
Net cash provided by operating activities	352,378	411,924	24,615
Acquisitions	116,867	(149,658)	39,328
Net cash used by investing activities	248,958	282,245	123,389
Dividends paid on common stock	(99,233)us-gaap_PaymentsOfDividendsCommonStock	(50,768)us-gaap_PaymentsOfDividendsCommonStock	(46,201)us-gaap_PaymentsOfDividendsCommonStock
Stock repurchased	(7,183)	(9,360)	(7,436)
Proceeds from exercise of stock options	6,116	6,398	981
Net cash provided (used) by financing activities	213,412	(447,533)	(202,983)
Net increase (decrease) in cash and cash equivalents	814,748	246,636	(54,979)
Cash and cash equivalents, beginning of year	790,423	543,787	598,766
Cash and cash equivalents, end of year	1,605,171	790,423	543,787
Umpqua Bank [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	147,520	98,361	101,891
Equity in undistributed earnings of subsidiaries	91,969	(43,381)	(30,054)
Depreciation, amortization and accretion	(322)	(322)	(322)
Change in fair value of junior subordinated debentures	5,849	2,193	2,182
Net (increase) decrease in other assets	(6,020)	(92)	4,925
Net increase (decrease) in other liabilities	(8,708)	(1,361)	(1,184)
Net cash provided by operating activities	230,288	55,398	77,438
Investment in subsidiaries	6	(2,928)	(24,970)
Acquisitions	(102,143)	0	419
Net cash used by investing activities	(102,137)	(2,928)	(24,551)
Net (decrease) increase in payables to subsidiaries	(4)	(8,448)	17
Dividends paid on common stock	(99,233)	(50,767)	(46,201)
Stock repurchased	(7,183)	(9,356)	(7,433)
Proceeds from exercise of stock options	7,692	6,397	980
Net cash provided (used) by financing activities	(98,728)	(62,174)	(52,637)
Net increase (decrease) in cash and cash equivalents	29,423	(9,704)	250
Cash and cash equivalents, beginning of year	72,679	82,383	82,133
Cash and cash equivalents, end of year	$ 102,102	$ 72,679	$ 82,383

Net change in junior subordinated debentures carried at fair value

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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