Parent Company Financial Statements (Schedule Of Condensed Statements Of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Other (loss) income									$ (62,459)	$ (67,917)
Other expenses									51,768	50,763	$ 55,461
Income tax benefit	$ 27,118	$ 26,166	$ 37,408	$ 24,116	$ 28,183	$ 31,772	$ 21,661	$ 24,807	114,808	106,423	106,730
Net Income (Loss) Attributable to Parent	$ 83,750	$ 84,502	$ 111,810	$ 74,033	$ 80,311	$ 90,981	$ 65,999	$ 78,972	354,095	316,263	242,313
Umpqua Holdings Corporation
Condensed Financial Statements, Captions [Line Items]
Dividends from subsidiaries									219,143	212,457	177,798
Other (loss) income									(18)	1,154	(14,678)
Total income									219,125	213,611	163,120
Management fees paid to subsidiaries									1,144	1,014	1,003
Other expenses									25,311	23,725	20,325
Total expenses									26,455	24,739	21,328
Income before income tax benefit and equity in undistributed earnings of subsidiaries									192,670	188,872	141,792
Income tax benefit									(5,742)	(5,052)	(25,679)
Net income before equity in undistributed earnings of subsidiaries									198,412	193,924	167,471
Equity in undistributed earnings of subsidiaries									155,683	122,339	74,842
Net Income (Loss) Attributable to Parent									$ 354,095	$ 316,263	$ 242,313