Junior Subordinated Debentures (Narrative) (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Disclosure [Abstract]
Common stock issued by Trusts	$ 14,300,000umpq_CommonStockIssuedByTrustOwned	$ 6,900,000umpq_CommonStockIssuedByTrustOwned
Loss on junior subordinated debentures carried at fair value	$ 5,090,000	$ 2,197,000	$ 2,203,000

Gain (Loss) On Changes In Fair Value Of Junior Subordinated Debentures

No definition available.

Name:	umpq_GainLossOnChangesInFairValueOfJuniorSubordinatedDebentures
Namespace Prefix:	umpq_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration