Fair Value Measurement (Narrative) (Details) (USD $)	6 Months Ended
Jun. 30, 2012
Fair Value Measurement [Abstract]
Other Company Stock Owned Fair Value Discount Percentage	5.00%
Carrying value of loans fully charged-off	$ 0
Transfer of trading securities from Level 1 to Level 2 measurements	$ 767,000

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

No definition available.

Name:	umpq_FairValueAssetsLevel1ToLevel2TransfersAmount1
Namespace Prefix:	umpq_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration