Parent Company Financial Statements (Schedule Of Condensed Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Financial Statements, Captions [Line Items]
Other income (loss)									$ (50,962)	$ (62,459)	$ (67,917)
Other expenses									45,956	55,631	51,630
Income tax benefit	$ (3,204)	$ 33,758	$ 6,062	$ 30,384	$ 27,118	$ 26,166	$ 37,408	$ 24,116	67,000	114,808	106,423
Net Income (Loss) Attributable to Parent	$ 150,730	$ 124,871	$ 52,926	$ (1,851,947)	$ 83,750	$ 84,502	$ 111,810	$ 74,033	(1,523,420)	354,095	316,263
Umpqua Holdings Corporation
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries									213,464	219,143	212,457
Other income (loss)									11	(18)	1,154
Total income									213,475	219,125	213,611
Management fees paid to subsidiaries									1,165	1,144	1,014
Other expenses									17,894	25,311	23,725
Total expenses									19,059	26,455	24,739
Income before income tax benefit and equity in undistributed earnings of subsidiaries									194,416	192,670	188,872
Income tax benefit									(4,245)	(5,742)	(5,052)
Net income before equity in undistributed earnings of subsidiaries									198,661	198,412	193,924
Equity in undistributed (losses) earnings of subsidiaries									(1,722,081)	155,683	122,339
Net Income (Loss) Attributable to Parent									$ (1,523,420)	$ 354,095	$ 316,263