Parent Company Financial Statements (Schedule Of Condensed Statements Of Operations) (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Condensed Financial Statements, Captions [Line Items]
Other income									$ 24,916,000		$ 12,674,000		$ 11,271,000
Other expenses									31,542,000		29,614,000		32,576,000
Income tax (benefit) expense	14,796,000	13,587,000	11,681,000	13,257,000	10,722,000	10,717,000	8,782,000	6,521,000	53,321,000		36,742,000		5,805,000
Net income (loss)	27,958,000	25,153,000	23,277,000	25,503,000	21,382,000	21,862,000	17,785,000	13,467,000	101,891,000		74,496,000		28,326,000
Preferred stock dividends													12,192,000
Dividends and undistributed earnings allocated to participating securities	183,000	170,000	162,000	167,000	103,000	105,000	86,000	62,000	682,000	[1]	356,000	[1]	67,000	[1]
Net earnings available to common shareholders	27,775,000	24,983,000	23,115,000	25,336,000	21,279,000	21,757,000	17,699,000	13,405,000	101,209,000		74,140,000		16,067,000
Umpqua Bank [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries									78,755,000		17,743,000		245,000
Other income									(2,174,000)		(2,127,000)		5,081,000
Total income									76,581,000		15,616,000		5,326,000
Management fees paid to subsidiaries									459,000		469,000		291,000
Other expenses									9,189,000		9,072,000		9,116,000
Total expenses									9,648,000		9,541,000		9,407,000
Income (loss) before income tax benefit and equity in undistributed earnings of subsidiaries									66,933,000		6,075,000		(4,081,000)
Income tax (benefit) expense									(4,904,000)		(4,325,000)		(1,594,000)
Net income (loss) before equity in undistributed earnings of subsidiaries									71,837,000		10,400,000		(2,487,000)
Equity in (distributions in excess) undistributed earnings of subsidiaries									30,054,000		64,096,000		30,813,000
Net income (loss)									101,891,000		74,496,000		28,326,000
Preferred stock dividends													12,192,000
Dividends and undistributed earnings allocated to participating securities									682,000		356,000		67,000
Net earnings available to common shareholders									$ 101,209,000		$ 74,140,000		$ 16,067,000

[1] Represents dividends paid and undistributed earnings allocated to nonvested restricted stock awards.