Fair Value Measurement (Schedule Of Carrying Value And Fair Value Of Financial Instruments Not Recorded At Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
FINANCIAL ASSETS:
Cash and cash equivalents	$ 282,455us-gaap_CashAndDueFromBanks	$ 178,685us-gaap_CashAndDueFromBanks
Trading securities	9,999us-gaap_TradingSecurities	5,958us-gaap_TradingSecurities
Investment securities available for sale	2,298,555us-gaap_AvailableForSaleSecurities	1,790,978us-gaap_AvailableForSaleSecurities
Investment securities held to maturity	5,211us-gaap_HeldToMaturitySecurities	5,563us-gaap_HeldToMaturitySecurities
Loans held for sale, at fair value	286,802us-gaap_LoansReceivableHeldForSaleNet	104,664us-gaap_LoansReceivableHeldForSaleNet
Non-covered loans and leases, net	15,327,732	7,728,166
Restricted equity securities	119,334us-gaap_FederalHomeLoanBankStock	30,685us-gaap_FederalHomeLoanBankStock
Residential mortgage servicing rights	117,259us-gaap_ServicingAssetAtFairValueAmount	47,765us-gaap_ServicingAssetAtFairValueAmount	27,428us-gaap_ServicingAssetAtFairValueAmount	18,184us-gaap_ServicingAssetAtFairValueAmount
Bank owned life insurance	294,296us-gaap_BankOwnedLifeInsurance	96,938us-gaap_BankOwnedLifeInsurance
FDIC indemnification asset	4,417us-gaap_FDICIndemnificationAsset	23,174us-gaap_FDICIndemnificationAsset	52,798us-gaap_FDICIndemnificationAsset
Derivatives	29,210us-gaap_DerivativeAssets	17,921us-gaap_DerivativeAssets
FINANCIAL LIABILITIES:
Deposits	16,892,099us-gaap_Deposits	9,117,660us-gaap_Deposits	9,379,275us-gaap_Deposits
Securities sold under agreements to repurchase	313,321	224,882
Term debt	1,006,395umpq_TermDebt	251,494umpq_TermDebt
Junior subordinated debentures, at amortized cost	101,576	101,899
Carrying Value [Member]
FINANCIAL ASSETS:
Cash and cash equivalents	1,605,171	790,423
Trading securities	9,999	5,958
Investment securities available for sale	2,298,555	1,790,978
Investment securities held to maturity	5,211	5,563
Loans held for sale, at fair value	286,802	104,664
Non-covered loans and leases, net	15,211,565	7,633,081
Restricted equity securities	119,334	30,685
Residential mortgage servicing rights	117,259	47,765
Bank owned life insurance	294,296	96,938
FDIC indemnification asset	4,417	23,174
Derivatives	29,210	17,921
Visa Class B common stock	0	0
FINANCIAL LIABILITIES:
Deposits	16,892,099	9,117,660
Securities sold under agreements to repurchase	313,321	224,882
Term debt	1,006,395	251,494
Junior subordinated debentures, at fair value	249,294	87,274
Junior subordinated debentures, at amortized cost	101,576	101,899
Derivatives	30,785	14,562
Estimated Fair Value [Member]
FINANCIAL ASSETS:
Cash and cash equivalents	1,605,171	790,423
Trading securities	9,999	5,958
Investment securities available for sale	2,298,555	1,790,978
Investment securities held to maturity	5,554	5,874
Loans held for sale, at fair value	286,802	104,664
Non-covered loans and leases, net	15,252,083	7,660,151
Restricted equity securities	119,334	30,685
Residential mortgage servicing rights	117,259	47,765
Bank owned life insurance	294,296	96,938
FDIC indemnification asset	2,058	6,001
Derivatives	29,210	17,921
Visa Class B common stock	49,663	41,700
FINANCIAL LIABILITIES:
Deposits	16,893,890	9,125,832
Securities sold under agreements to repurchase	313,321	224,882
Term debt	1,018,948	270,004
Junior subordinated debentures, at fair value	249,294	87,274
Junior subordinated debentures, at amortized cost	73,840	72,009
Derivatives	$ 30,785	$ 14,562

The carrying value as of the balance sheet date of junior subordinated debentures, at amortized cost.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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The carrying amount of a life insurance policy on an officer, executive or employee for which the reporting entity (a bank) is entitled to proceeds from the policy upon death of the insured or surrender of the insurance policy.

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For banks and other depository institutions: Includes cash on hand (currency and coin), cash items in process of collection, noninterest bearing deposits due from other financial institutions (including corporate credit unions), and noninterest bearing balances with the Federal Reserve Banks, Federal Home Loan Banks and central banks.

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The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Carrying amount of receivable assets originating from the indemnification agreement with the Federal Deposit Insurance Corporation (FDIC), in which the FDIC is to partially cover losses.

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Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of loans held for sale, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

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Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security resale agreement between the entity and another party for the purchase and resale of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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