Parent Company Financial Statements (Schedule Of Condensed Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Net income	$ 69,275	$ 61,809	$ 54,287	$ 47,569	$ 63,019	$ 57,607	$ 54,784	$ 47,129	$ 232,940	$ 222,539	$ 147,658
Depreciation, amortization and accretion									59,256	51,593	39,209
Change in fair value of junior subordinated debentures									6,752	6,163	5,849
Net decrease (increase) in other assets									(27,080)	24,692	(49,165)
Net decrease in other liabilities									11,622	15,290	38,632
Net cash provided by operating activities									421,643	376,740	357,570
Net cash (used) provided by investing activities									(919,040)	(1,756,911)	242,140
Dividends paid on common stock									(141,074)	(134,618)	(99,233)
Stock repurchased									(17,708)	(14,589)	(7,183)
Proceeds from exercise of stock options									2,626	1,481	9,368
Net cash provided by financing activities									1,173,104	548,725	215,038
Net (decrease) increase in cash and cash equivalents									675,707	(831,446)	814,748
Cash and cash equivalents, beginning of year				773,725				1,605,171	773,725	1,605,171	790,423
Cash and cash equivalents, end of year	1,449,432				773,725				1,449,432	773,725	1,605,171
Umpqua Bank
Condensed Financial Statements, Captions [Line Items]
Net income									232,940	222,539	147,658
Equity in undistributed earnings of subsidiaries									(84,191)	(84,116)	91,831
Depreciation, amortization and accretion									(322)	(322)	(322)
Change in fair value of junior subordinated debentures									6,752	6,163	5,849
Net decrease (increase) in other assets									972	617	(6,020)
Net decrease in other liabilities									(2,112)	(2,903)	(8,708)
Net cash provided by operating activities									154,039	141,978	230,288
Change in subsidiaries									3,258	(5,000)	6
Acquisitions									0	0	(102,143)
Net cash (used) provided by investing activities									3,258	(5,000)	(102,137)
Net increase (decrease) in payables to subsidiaries									45	0	(4)
Dividends paid on common stock									(141,074)	(134,618)	(99,233)
Stock repurchased									(17,708)	(14,589)	(7,183)
Proceeds from exercise of stock options									2,626	1,481	7,692
Net cash provided by financing activities									(156,111)	(147,726)	(98,728)
Net (decrease) increase in cash and cash equivalents									1,186	(10,748)	29,423
Cash and cash equivalents, beginning of year				$ 91,354				$ 102,102	91,354	102,102	72,679
Cash and cash equivalents, end of year	$ 92,540				$ 91,354				$ 92,540	$ 91,354	$ 102,102