Parent Company Financial Statements (Schedule Of Condensed Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Other income									$ 46,287	$ 26,465	$ 20,080
Other expenses									39,137	36,465	27,265
Income tax benefit	$ 35,704	$ 31,633	$ 30,612	$ 26,639	$ 29,641	$ 32,107	$ 11,356	$ 9,936	124,588	83,040	54,192
Net income	63,019	57,607	54,784	47,129	52,582	58,883	17,542	18,651	222,539	147,658	98,291
Dividends and undistributed earnings allocated to participating securities	96	84	93	84	146	142	83	113	357	484	788
Net earnings available to common shareholders	$ 62,923	$ 57,523	$ 54,691	$ 47,045	$ 52,436	$ 58,741	$ 17,459	$ 18,538	222,182	147,174	97,503
Umpqua Bank [Member]
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries									153,437	250,848	62,241
Other income									(6,272)	(5,196)	(2,321)
Total income									147,165	245,652	59,920
Management fees paid to subsidiaries									447	533	501
Other expenses									15,564	12,966	8,885
Total expenses									16,011	13,499	9,386
Income before income tax benefit and equity in undistributed earnings of subsidiaries									131,154	232,153	50,534
Income tax benefit									(7,269)	(7,336)	(4,446)
Net income before equity in undistributed earnings of subsidiaries									138,423	239,489	54,980
Equity in undistributed earnings of subsidiaries									84,116	(91,831)	43,311
Net income									222,539	147,658	98,291
Dividends and undistributed earnings allocated to participating securities									$ 357	$ 484	$ 788