Summary of Significant Accounting Policies (Policies)	12 Months Ended
Sep. 30, 2012
Accounting Policies [Abstract]
Principles of consolidation	Principles of consolidation. The consolidated financial statements include the accounts of Washington Federal, Inc. (Company or Washington Federal) and its wholly owned subsidiaries. Intercompany transactions and balances have been eliminated.
Fiscal period	The Company's fiscal year end is September 30th. All references to 2012, 2011 and 2010 represent balances as of September 30, 2012, September 30, 2011 and September 30, 2010, or activity for the fiscal years then ended. References to net income in this document refer to net income available to common shareholders.
Cash and cash equivalents	Cash and cash equivalents. Cash and cash equivalents include cash on hand, amounts due from banks, overnight investments and repurchase agreements with an initial maturity of three months or less.
Investments and mortgage-backed securities	Investments and mortgage-backed securities. The Company accounts for investments and mortgage-backed securities in two categories: held-to-maturity and available-for-sale.
Held-to-maturity securities	Held-to-maturity securities - Securities classified as held-to-maturity are accounted for at amortized cost, but the Company must have both the positive intent and the ability to hold those securities to maturity. There are very limited circumstances under which securities in the held-to-maturity category can be sold without jeopardizing the cost basis of accounting for the remainder of the securities in this category.
Available-for-sale securities	Available-for-sale securities - Securities not classified as held-to-maturity are considered to be available-for-sale. Gains and losses realized on the sale of these securities are accounted for based on the specific identification method. Unrealized gains and losses for available-for-sale securities are excluded from earnings and reported as a net amount in the accumulated other comprehensive income component of stockholders' equity.
Other than temporary impairment	Management evaluates debt and equity securities for other than temporary impairment on a quarterly basis based on the securities' current credit quality, interest rates, term to maturity and management's intent and ability to hold the securities until the net book value is recovered. Any other than temporary declines in fair value are recognized in the statements of operations. Premiums and discounts on investments are deferred and recognized over the life of the asset, using the effective interest method. Realized gains and losses on securities sold as well as other than temporary impairment charges, are shown on the Consolidated Statements of Operations under the Other Income (Loss) heading.
Loans receivable	Loans receivable - When a borrower fails to make a required payment on a loan, the Company attempts to cure the deficiency by contacting the borrower. Contact is made after a payment is 30 days past its grace period. In most cases, deficiencies are cured promptly. If the delinquency is not cured within 90 days, the Company may institute appropriate action to foreclose on the property. If foreclosed, the property is sold at a public sale and may be purchased by the Company. The Company will consider modifying the interest rates and terms of a loan if it determines that a modification is a better alternative to foreclosure. Loans are placed on nonaccrual status when, in the judgment of management, the probability of collection of interest is deemed to be insufficient to warrant further accrual. When a loan is placed on nonaccrual status, previously accrued but unpaid interest is deducted from interest income. The Company does not accrue interest on loans 90 days or more past due. If payment is made on a loan so that the loan becomes less than 90 days past due, and the Company expects full collection of principal and interest, the loan is returned to full accrual status. Any interest ultimately collected is credited to income in the period of recovery. A loan is charged-off when the loss is estimable and it is confirmed that the borrower will not be able to meet contractual obligations. The Company maintains an allowance for loan losses to absorb losses inherent in the loan portfolio. The allowance is based on ongoing, quarterly assessments of the probable and estimable losses inherent in the loan portfolio. The Company's methodology for assessing the appropriateness of the allowance consists of two components, which include the general allowance and specific allowances. The general loan loss allowance is established by applying a loss percentage factor to the different loan types. Management believes loan types are the most relevant factor to group loans for the allowance calculation as the risk characteristics in these groups are similar. The loss percentage factor is made up of two parts - the historical loss factor (“HLF”) and the qualitative loss factor (“QLF”). The HLF takes into account historical charge-offs, while the QLF is determined by loan type and allows management to augment reserve levels to reflect the current environment and portfolio performance trends including recent charge-off trends. Allowances are provided based on management's continuing evaluation of the pertinent factors underlying the quality of the loan portfolio, including changes in the size and composition of the loan portfolio, actual loan loss experience, current economic conditions, collateral values, geographic concentrations, seasoning of the loan portfolio, specific industry conditions, and the duration of the current business cycle. The recovery of the carrying value of loans is susceptible to future market conditions beyond the Company's control, which may result in losses or recoveries differing from those provided. Specific allowances are established for loans which are individually evaluated, in cases where management has identified significant conditions or circumstances related to a loan that management believes indicate the probability that a loss has been incurred. Impaired loans consist of loans receivable that are not expected to have their principal and interest repaid in accordance with their contractual terms. Collateral dependent impaired loans are measured using the fair value of the collateral, less selling costs. Non-collateral dependent loans are measured at the present value of expected future cash flows. The Company receives fees for originating loans in addition to various fees and charges related to existing loans, which may include prepayment charges, late charges and assumption fees. Deferred loan fees and costs are recognized over the life of the loans using the effective interest method.
Covered loans	Covered loans. Covered loans are the loans acquired from Horizon in 2010 and recorded at their estimated fair market value. Loans that were classified as non-performing loans by Horizon are no longer classified as non-performing because, at acquisition, the carrying value of these loans was adjusted to reflect fair value and are covered under the FDIC loss sharing agreements. Management believes that the new book value reflects an amount that will ultimately be collected.
Acquired credit impaired loans	Acquired credit impaired loans. Loans are accounted for under ASC 310-30 when there is evidence of credit deterioration since origination and for which it is probable, at acquisition, that the Company would be unable to collect all contractually required payments. Interest income, through accretion of the difference between the carrying amount of the loans and the expected cash flows, was recognized on all acquired loans.
Covered real estate held for sale	Covered real estate held for sale. Covered real estate held for sale represents the foreclosed properties that were originally Horizon loans. Covered real estate held for sale is carried at the estimated fair market value of the repossessed real estate. The covered loans and covered real estate held for sale are collectively referred to as “covered assets”.
FDIC indemnification asset	FDIC indemnification asset. FDIC indemnification asset is the receivable recorded from due to guarantee provided by the FDIC on the covered assets.
Premises and equipment	Premises and equipment. Premises and equipment are stated at cost, less accumulated depreciation. Depreciation is computed on the straight-line method over the estimated useful lives of the respective assets. Expenditures are capitalized for betterments and major renewals. Charges for ordinary maintenance and repairs are expensed to operations as incurred.
Real estate held for sale	Real estate held for sale. Properties acquired in settlement of loans or acquired for development are recorded at the lower of cost or fair value less selling costs. Subsequent declines in valuation are recorded as additional expense in gain (loss) on real estate acquired through foreclosure line item.
Intangible assets	Intangible assets. Goodwill represents the excess of the cost of businesses acquired over the fair value of the net assets acquired. The core deposit intangibles and non-compete agreement intangible are acquired assets that lack physical substance but can be distinguished from goodwill. Goodwill is evaluated for impairment on an annual basis. Other intangible assets are amortized over their estimated lives and are subject to impairment testing when events or circumstances change. If circumstances indicate that the carrying value of the assets may not be recoverable, an impairment charge could be recorded. No impairment of intangible assets has ever been identified. The Company amortizes the core deposit intangibles on a straight line basis over their estimated lives of between 5 and 8 years.
Deferred fees and discounts on loans	Deferred fees and discounts on loans. Loan discounts and loan fees are deferred and recognized over the life of the loans using the effective interest method.
Accounting for stock-based compensation	Accounting for stock-based compensation. The Company records an expense for the estimated fair value of equity awards over the vesting period. See Note L for additional information. Stock options that were not dilutive but were outstanding as of September 30, 2012, 2011 and 2010 were 934,880, 2,190,123 and 1,941,633, respectively.
Use of estimates	Use of estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates reported in the financial statements include the allowance for loan losses, intangible assets, deferred taxes and contingent liabilities. Actual results could differ from these estimates.
Business segments	Business segments. As the Company manages its business and operations on a consolidated basis, management has determined that there is one reportable business segment.
Reclassifications	Reclassifications. Certain reclassifications have been made to the financial statements for years prior to September 30, 2012 to conform to current year classifications.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Sep. 30, 2012

Principles of consolidation. The consolidated financial statements include the accounts of Washington Federal, Inc. (Company or Washington Federal) and its wholly owned subsidiaries. Intercompany transactions and balances have been eliminated.

Fiscal period

The Company's fiscal year end is September 30th. All references to 2012, 2011 and 2010 represent balances as of September 30, 2012, September 30, 2011 and September 30, 2010, or activity for the fiscal years then ended. References to net income in this document refer to net income available to common shareholders.

Cash and cash equivalents

Cash and cash equivalents. Cash and cash equivalents include cash on hand, amounts due from banks, overnight investments and repurchase agreements with an initial maturity of three months or less.

Investments and mortgage-backed securities

Investments and mortgage-backed securities. The Company accounts for investments and mortgage-backed securities in two categories: held-to-maturity and available-for-sale.

Held-to-maturity securities

Held-to-maturity securities - Securities classified as held-to-maturity are accounted for at amortized cost, but the Company must have both the positive intent and the ability to hold those securities to maturity. There are very limited circumstances under which securities in the held-to-maturity category can be sold without jeopardizing the cost basis of accounting for the remainder of the securities in this category.

Available-for-sale securities

Available-for-sale securities - Securities not classified as held-to-maturity are considered to be available-for-sale. Gains and losses realized on the sale of these securities are accounted for based on the specific identification method. Unrealized gains and losses for available-for-sale securities are excluded from earnings and reported as a net amount in the accumulated other comprehensive income component of stockholders' equity.

Other than temporary impairment

Management evaluates debt and equity securities for other than temporary impairment on a quarterly basis based on the securities' current credit quality, interest rates, term to maturity and management's intent and ability to hold the securities until the net book value is recovered. Any other than temporary declines in fair value are recognized in the statements of operations.

Premiums and discounts on investments are deferred and recognized over the life of the asset, using the effective interest method.

Realized gains and losses on securities sold as well as other than temporary impairment charges, are shown on the Consolidated Statements of Operations under the Other Income (Loss) heading.

Loans receivable

Loans receivable - When a borrower fails to make a required payment on a loan, the Company attempts to cure the deficiency by contacting the borrower. Contact is made after a payment is 30 days past its grace period. In most cases, deficiencies are cured promptly. If the delinquency is not cured within 90 days, the Company may institute appropriate action to foreclose on the property. If foreclosed, the property is sold at a public sale and may be purchased by the Company.

The Company will consider modifying the interest rates and terms of a loan if it determines that a modification is a better alternative to foreclosure.

Loans are placed on nonaccrual status when, in the judgment of management, the probability of collection of interest is deemed to be insufficient to warrant further accrual. When a loan is placed on nonaccrual status, previously accrued but unpaid interest is deducted from interest income. The Company does not accrue interest on loans 90 days or more past due. If payment is made on a loan so that the loan becomes less than 90 days past due, and the Company expects full collection of principal and interest, the loan is returned to full accrual status. Any interest ultimately collected is credited to income in the period of recovery. A loan is charged-off when the loss is estimable and it is confirmed that the borrower will not be able to meet contractual obligations.

The Company maintains an allowance for loan losses to absorb losses inherent in the loan portfolio. The allowance is based on ongoing, quarterly assessments of the probable and estimable losses inherent in the loan portfolio. The Company's methodology for assessing the appropriateness of the allowance consists of two components, which include the general allowance and specific allowances.

The general loan loss allowance is established by applying a loss percentage factor to the different loan types. Management believes loan types are the most relevant factor to group loans for the allowance calculation as the risk characteristics in these groups are similar. The loss percentage factor is made up of two parts - the historical loss factor (“HLF”) and the qualitative loss factor (“QLF”). The HLF takes into account historical charge-offs, while the QLF is determined by loan type and allows management to augment reserve levels to reflect the current environment and portfolio performance trends including recent charge-off trends. Allowances are provided based on management's continuing evaluation of the pertinent factors underlying the quality of the loan portfolio, including changes in the size and composition of the loan portfolio, actual loan loss experience, current economic conditions, collateral values, geographic concentrations, seasoning of the loan portfolio, specific industry conditions, and the duration of the current business cycle. The recovery of the carrying value of loans is susceptible to future market conditions beyond the Company's control, which may result in losses or recoveries differing from those provided.

Specific allowances are established for loans which are individually evaluated, in cases where management has identified significant conditions or circumstances related to a loan that management believes indicate the probability that a loss has been incurred.

Impaired loans consist of loans receivable that are not expected to have their principal and interest repaid in accordance with their contractual terms. Collateral dependent impaired loans are measured using the fair value of the collateral, less selling costs. Non-collateral dependent loans are measured at the present value of expected future cash flows.

The Company receives fees for originating loans in addition to various fees and charges related to existing loans, which may include prepayment charges, late charges and assumption fees. Deferred loan fees and costs are recognized over the life of the loans using the effective interest method.

Covered loans

Covered loans. Covered loans are the loans acquired from Horizon in 2010 and recorded at their estimated fair market value. Loans that were classified as non-performing loans by Horizon are no longer classified as non-performing because, at acquisition, the carrying value of these loans was adjusted to reflect fair value and are covered under the FDIC loss sharing agreements. Management believes that the new book value reflects an amount that will ultimately be collected.

Acquired credit impaired loans

Acquired credit impaired loans. Loans are accounted for under ASC 310-30 when there is evidence of credit deterioration since origination and for which it is probable, at acquisition, that the Company would be unable to collect all contractually required payments. Interest income, through accretion of the difference between the carrying amount of the loans and the expected cash flows, was recognized on all acquired loans.

Covered real estate held for sale

Covered real estate held for sale. Covered real estate held for sale represents the foreclosed properties that were originally Horizon loans. Covered real estate held for sale is carried at the estimated fair market value of the repossessed real estate. The covered loans and covered real estate held for sale are collectively referred to as “covered assets”.

FDIC indemnification asset

FDIC indemnification asset. FDIC indemnification asset is the receivable recorded from due to guarantee provided by the FDIC on the covered assets.

Premises and equipment

Premises and equipment. Premises and equipment are stated at cost, less accumulated depreciation. Depreciation is computed on the straight-line method over the estimated useful lives of the respective assets. Expenditures are capitalized for betterments and major renewals. Charges for ordinary maintenance and repairs are expensed to operations as incurred.

Real estate held for sale

Real estate held for sale. Properties acquired in settlement of loans or acquired for development are recorded at the lower of cost or fair value less selling costs. Subsequent declines in valuation are recorded as additional expense in gain (loss) on real estate acquired through foreclosure line item.

Intangible assets

Intangible assets. Goodwill represents the excess of the cost of businesses acquired over the fair value of the net assets acquired. The core deposit intangibles and non-compete agreement intangible are acquired assets that lack physical substance but can be distinguished from goodwill. Goodwill is evaluated for impairment on an annual basis. Other intangible assets are amortized over their estimated lives and are subject to impairment testing when events or circumstances change. If circumstances indicate that the carrying value of the assets may not be recoverable, an impairment charge could be recorded. No impairment of intangible assets has ever been identified. The Company amortizes the core deposit intangibles on a straight line basis over their estimated lives of between 5 and 8 years.

Deferred fees and discounts on loans

Deferred fees and discounts on loans. Loan discounts and loan fees are deferred and recognized over the life of the loans using the effective interest method.

Accounting for stock-based compensation

Accounting for stock-based compensation. The Company records an expense for the estimated fair value of equity awards over the vesting period. See Note L for additional information. Stock options that were not dilutive but were outstanding as of September 30, 2012, 2011 and 2010 were 934,880, 2,190,123 and 1,941,633, respectively.

Use of estimates

Use of estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Significant estimates reported in the financial statements include the allowance for loan losses, intangible assets, deferred taxes and contingent liabilities. Actual results could differ from these estimates.

Business segments

Business segments. As the Company manages its business and operations on a consolidated basis, management has determined that there is one reportable business segment.

Reclassifications

Reclassifications. Certain reclassifications have been made to the financial statements for years prior to September 30, 2012 to conform to current year classifications.