Employee Benefit Plans	12 Months Ended
Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans Employee Savings Plan-Substantially all of the Bank's and Umpqua Investments' employees are eligible to participate in the Umpqua Bank 401(k) and Profit Sharing Plan (the "Umpqua 401(k) Plan"), a defined contribution and profit sharing plan sponsored by the Company. Employees may elect to have a portion of their salary contributed to the plan in conformity with Section 401(k) of the Internal Revenue Code. At the discretion of the Company's Board of Directors, the Company may elect to make matching and/or profit sharing contributions to the Umpqua 401(k) Plan based on profits of the Bank. The Company's contributions charged to expense amounted to $7.4 million, $5.0 million, and $3.8 million for the years ended December 31, 2015, 2014 and 2013, respectively. Supplemental Retirement Plans-The Company has established the Umpqua Holdings Corporation Deferred Compensation & Supplemental Retirement Plan (the "DC/SRP"), a nonqualified deferred compensation plan to help supplement the retirement income of certain highly compensated executives selected by resolution of the Company's Board of Directors. The DC/SRP has two components, a supplemental retirement plan ("SRP") and a deferred compensation plan ("DCP"). The Company may make discretionary contributions to the SRP. For the years ended December 31, 2015, 2014 and 2013, the Company's matching contribution charged to expense for these supplemental plans totaled $178,000, $140,000, and $123,000, respectively. The SRP plan balances at December 31, 2015 and 2014 were $889,000 and $812,000, respectively, and are recorded in other liabilities. Under the DCP, eligible officers may elect to defer up to 50% of their salary into a plan account. The DCP plan balance was $4.9 million and $3.9 million at December 31, 2015 and 2014, respectively. In addition, the Company has established a supplemental retirement plan for the CEO. The plan balance for this plan was $8.7 million as of both December 31, 2015 and 2014. Acquired Plans- In connection with prior acquisitions, the Bank assumed liability for certain salary continuation, supplemental retirement, and deferred compensation plans for key employees, retired employees and directors of acquired institutions. Subsequent to the effective date of these acquisitions, no additional contributions were made to these plans. These plans are unfunded, and provide for the payment of a specified amount on a monthly basis for a specified period (generally 10 to 20 years) after retirement. In the event of a participant employee's death prior to or during retirement, the Bank in most cases is obligated to pay to the designated beneficiary the benefits set forth under the plans. At December 31, 2015 and 2014, liabilities recorded for the estimated present value of future plan benefits totaled $36.1 million and $42.3 million, respectively, and are recorded in other liabilities. For the years ended December 31, 2015, 2014 and 2013, expense recorded for these plan's benefits totaled $1.1 million, $2.9 million, and $849,000, respectively. Rabbi Trusts-The Bank has established, for the DC/SRP plan noted above, and sponsors, for some deferred compensation plans assumed in connection with prior mergers, irrevocable trusts commonly referred to as "Rabbi Trusts." The trust assets (generally cash and trading assets) are consolidated in the Company's balance sheets and the associated liability (which equals the related asset balances) is included in other liabilities. The asset and liability balances related to these trusts as of December 31, 2015 and 2014 were $9.6 million and $9.1 million, respectively. The Bank has purchased, or acquired through mergers, life insurance policies in connection with the implementation of certain executive supplemental income, salary continuation and deferred compensation retirement plans. These policies provide protection against the adverse financial effects that could result from the death of a key employee and provide tax-exempt income to offset expenses associated with the plans. It is the Bank's intent to hold these policies as a long-term investment. However, there will be an income tax impact if the Bank chooses to surrender certain policies. Although the lives of individual current or former management-level employees are insured, the Bank is the owner and sole or partial beneficiary. At December 31, 2015 and 2014, the cash surrender value of these policies was $291.9 million and $294.3 million, respectively. At December 31, 2015 and 2014, the Bank also had liabilities for post-retirement benefits payable to other partial beneficiaries under some of these life insurance policies of $6.2 million and $6.2 million, respectively. The Bank is exposed to credit risk to the extent an insurance company is unable to fulfill its financial obligations under a policy. In order to mitigate this risk, the Bank uses a variety of insurance companies and regularly monitors their financial condition.

Employee Benefit Plans

Employee Savings Plan-Substantially all of the Bank's and Umpqua Investments' employees are eligible to participate in the Umpqua Bank 401(k) and Profit Sharing Plan (the "Umpqua 401(k) Plan"), a defined contribution and profit sharing plan sponsored by the Company. Employees may elect to have a portion of their salary contributed to the plan in conformity with Section 401(k) of the Internal Revenue Code. At the discretion of the Company's Board of Directors, the Company may elect to make matching and/or profit sharing contributions to the Umpqua 401(k) Plan based on profits of the Bank. The Company's contributions charged to expense amounted to $7.4 million, $5.0 million, and $3.8 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Supplemental Retirement Plans-The Company has established the Umpqua Holdings Corporation Deferred Compensation & Supplemental Retirement Plan (the "DC/SRP"), a nonqualified deferred compensation plan to help supplement the retirement income of certain highly compensated executives selected by resolution of the Company's Board of Directors. The DC/SRP has two components, a supplemental retirement plan ("SRP") and a deferred compensation plan ("DCP"). The Company may make discretionary contributions to the SRP. For the years ended December 31, 2015, 2014 and 2013, the Company's matching contribution charged to expense for these supplemental plans totaled $178,000, $140,000, and $123,000, respectively. The SRP plan balances at December 31, 2015 and 2014 were $889,000 and $812,000, respectively, and are recorded in other liabilities. Under the DCP, eligible officers may elect to defer up to 50% of their salary into a plan account. The DCP plan balance was $4.9 million and $3.9 million at December 31, 2015 and 2014, respectively. In addition, the Company has established a supplemental retirement plan for the CEO. The plan balance for this plan was $8.7 million as of both December 31, 2015 and 2014.

Acquired Plans- In connection with prior acquisitions, the Bank assumed liability for certain salary continuation, supplemental retirement, and deferred compensation plans for key employees, retired employees and directors of acquired institutions. Subsequent to the effective date of these acquisitions, no additional contributions were made to these plans. These plans are unfunded, and provide for the payment of a specified amount on a monthly basis for a specified period (generally 10 to 20 years) after retirement. In the event of a participant employee's death prior to or during retirement, the Bank in most cases is obligated to pay to the designated beneficiary the benefits set forth under the plans. At December 31, 2015 and 2014, liabilities recorded for the estimated present value of future plan benefits totaled $36.1 million and $42.3 million, respectively, and are recorded in other liabilities. For the years ended December 31, 2015, 2014 and 2013, expense recorded for these plan's benefits totaled $1.1 million, $2.9 million, and $849,000, respectively.

Rabbi Trusts-The Bank has established, for the DC/SRP plan noted above, and sponsors, for some deferred compensation plans assumed in connection with prior mergers, irrevocable trusts commonly referred to as "Rabbi Trusts." The trust assets (generally cash and trading assets) are consolidated in the Company's balance sheets and the associated liability (which equals the related asset balances) is included in other liabilities. The asset and liability balances related to these trusts as of December 31, 2015 and 2014 were $9.6 million and $9.1 million, respectively.

The Bank has purchased, or acquired through mergers, life insurance policies in connection with the implementation of certain executive supplemental income, salary continuation and deferred compensation retirement plans. These policies provide protection against the adverse financial effects that could result from the death of a key employee and provide tax-exempt income to offset expenses associated with the plans. It is the Bank's intent to hold these policies as a long-term investment. However, there will be an income tax impact if the Bank chooses to surrender certain policies. Although the lives of individual current or former management-level employees are insured, the Bank is the owner and sole or partial beneficiary. At December 31, 2015 and 2014, the cash surrender value of these policies was $291.9 million and $294.3 million, respectively. At December 31, 2015 and 2014, the Bank also had liabilities for post-retirement benefits payable to other partial beneficiaries under some of these life insurance policies of $6.2 million and $6.2 million, respectively. The Bank is exposed to credit risk to the extent an insurance company is unable to fulfill its financial obligations under a policy. In order to mitigate this risk, the Bank uses a variety of insurance companies and regularly monitors their financial condition.