Organization and Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2014
Organization and Summary of Significant Accounting Policies [Abstract]
Organization and Summary of Significant Accounting Policies	1.Organization and Summary of Significant Accounting Policies (a)The Company and Basis of Presentation AeroCentury Corp. ("the Company'), a Delaware corporation incorporated in 1997, typically acquires used regional aircraft and engines for lease to foreign and domestic regional carriers. As discussed in Note 2, during the first quarter of 2014, the Company changed its method of accounting for non-refundable maintenance reserves and certain lessor maintenance obligations. The Company has applied this change in accounting principle retrospectively to all periods presented in accordance with ASC 250, Accounting Changes and Error Corrections (“ASC 250”). (b)Use of Estimates The Company’s financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable for making judgments that are not readily apparent from other sources. The most significant estimates with regard to these financial statements are the residual values and useful lives of the assets, the amount and timing of cash flows associated with each asset that are used to evaluate whether assets are impaired, accrued maintenance costs, accounting for income taxes, and the amounts recorded as allowances for doubtful accounts. (c)Cash and cash equivalents The Company considers highly liquid investments readily convertible into known amounts of cash, with original maturities of 90 days or less from the date of acquisition, as cash equivalents. (d)Aircraft Capitalization and Depreciation The Company’s interests in aircraft and aircraft engines are recorded at cost, which includes acquisition costs. Since inception, the Company has typically purchased only used aircraft and aircraft engines. It is the Company’s policy to hold aircraft for approximately twelve years unless market conditions dictate otherwise. Therefore, depreciation of aircraft is initially computed using the straight-line method over the anticipated holding period, usually twelve years, to an estimated residual value based on appraisal. For an aircraft engine held for lease as a spare, the Company estimates the length of time that it will hold the aircraft engine based upon estimated usage, repair costs and other factors, and depreciates it to the appraised residual value over such period using the straight-line method. The Company periodically reviews plans for lease or sale of its aircraft and aircraft engines and changes, as appropriate, the remaining expected holding period for such assets. Estimated residual values are reviewed and adjusted periodically, based upon updated estimates obtained from an independent appraiser. Decreases in the fair value of aircraft could affect not only the current value, discussed below, but also the estimated residual value. Assets that are held for sale are not subject to depreciation and are separately classified on the balance sheet. Such assets are carried at the lower of their carrying value or estimated fair values, less costs to sell. (e)Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs, to the extent possible. The fair value hierarchy under GAAP is based on three levels of inputs. Level 1 - Quoted prices in active markets for identical assets or liabilities. Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis The carrying amount of the Company's money market funds included in cash and cash equivalents was $1,044,300 and $1,842,000 at December 31, 2014 and December 31, 2013. The fair value of the Company's money market funds would be categorized as Level 1 under the GAAP fair value hierarchy. As of December 31, 2014 and December 31, 2013, there were no liabilities that were required to be measured and recorded at fair value on a recurring basis. Assets Measured and Recorded at Fair Value on a Nonrecurring Basis The Company determines fair value of long-lived assets held and used, such as aircraft and aircraft engines held for lease and held for sale, by reference to independent appraisals, quoted market prices (e.g., offers to purchase) and other factors. An impairment charge is recorded when the Company believes that the carrying value of an asset will not be recovered through future net cash flows and that the carrying value exceeds its fair value. During 2014, based on appraised values, the Company recorded impairment charges totaling $3,124,200 for two Fokker 100 aircraft and two Fokker 50 aircraft that are held for lease, resulting in a carrying value of $7,837,300. The fair value of such assets would be categorized as Level 2 under the GAAP fair value hierarchy. No impairments were recorded on the Company's aircraft and aircraft engines held for lease in 2013. During 2014, based on management's estimate of realizable value, the Company recorded impairment charges totaling $15,612,300 for five Fokker 100 aircraft and one Fokker 50 aircraft that are held for sale, resulting in a carrying value of $6,100,000. The fair value of such assets would be categorized as Level 3 under the GAAP fair value hierarchy. No impairments were recorded on the Company's aircraft and aircraft engines held for sale in 2013. Fair Value of Other Financial Instruments The Company’s financial instruments, other than cash and cash equivalents, consist principally of finance leases receivable and amounts borrowed under its credit facility (the “Credit Facility,” as defined in Note 7). The fair value of accounts receivable, finance leases receivable, accounts payable and the Company’s maintenance reserves and accrued maintenance costs approximates the carrying value of these financial instruments. Borrowings under the Company’s Credit Facility bear floating rates of interest that reset periodically to a market benchmark rate plus a credit margin. The Company believes the effective interest rate of this debt agreement approximates current market rates for such indebtedness at the balance sheet date, and therefore that the carrying amount of its floating rate debt at the balance sheet dates approximates its fair value. The fair value of the Company’s outstanding balance of its Credit Facility would be categorized as Level 3 under the GAAP fair value hierarchy. (f)Impairment of Long-lived Assets The Company reviews assets for impairment when there has been an event or a change in circumstances indicating that the carrying amount of a long-lived asset may not be recoverable. In addition, the Company routinely reviews all long-lived assets for impairment annually. Recoverability of an asset is measured by comparison of its carrying amount to the future estimated undiscounted cash flows (without interest charges) that the asset is expected to generate. Estimates are based on currently available market data and independent appraisals and are subject to fluctuation from time to time. If these estimated future cash flows are less than the carrying value of an asset at the time of evaluation, any impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds its fair value. Fair value is determined by reference to independent appraisals and other factors considered relevant by management. Significant management judgment is required in the forecasting of future operating results that are used in the preparation of estimated future undiscounted cash flows and, if different conditions prevail in the future, material write-downs may occur. As discussed in (e) Fair Value Measurements above, the Company recorded impairment provisions totaling $18,736,500 in 2014. No impairment provisions were recorded in 2013. (g)Deferred Financing Costs and Commitment Fees Costs incurred in connection with debt financing are deferred and amortized over the term of the debt using the effective interest method or, in certain instances where the differences are not material, using the straight-line method. Costs incurred in connection with the Company’s Credit Facility are deferred and amortized using the straight-line method. Commitment fees for unused funds are expensed as incurred. (h)Security deposits The Company’s leases are typically structured so that if any event of default occurs under a lease, the Company may apply all or a portion of the lessee’s security deposit to cure such default. If such application of the security deposit is made, the lessee typically is required to replenish and maintain the full amount of the deposit during the remaining term of the lease. All of the security deposits received by the Company are refundable to the lessee at the end of the lease upon satisfaction of all lease terms. (i)Taxes As part of the process of preparing the Company’s financial statements, management estimates income taxes in each of the jurisdictions in which the Company operates. This process involves estimating the Company’s current tax exposure under the most recent tax laws and assessing temporary differences resulting from differing treatment of items for tax and GAAP purposes. These differences result in deferred tax assets and liabilities, which are included in the balance sheet. Management also assesses the likelihood that the Company’s deferred tax assets will be recovered from future taxable income, and, to the extent management believes it is more likely than not that some portion or all of the deferred tax assets will not be realized, the Company establishes a valuation allowance. To the extent the Company establishes a valuation allowance or changes the allowance in a period, the Company reflects the corresponding increase or decrease within the tax provision in the statement of operations. Significant management judgment is required in determining the Company’s future taxable income for purposes of assessing the Company’s ability to realize any benefit from its deferred taxes. The Company accrues non-income based sales, use, value added and franchise taxes as other tax expense in the statements of operations. (j)Revenue Recognition, Accounts Receivable and Allowance for Doubtful Accounts Revenue from leasing of aircraft assets is recognized as operating lease revenue on a straight-line basis over the terms of the applicable lease agreements. Deferred payments are recorded as accrued rent when the cash rent received is lower than the straight-line revenue recognized. Such receivables decrease over the term of the applicable leases. Interest income is recognized on finance leases based on the interest rate implicit in the lease and the outstanding balance of the lease receivable. Maintenance reserves retained by the Company at lease-end are recognized as maintenance reserves revenue. In instances where collectability is not reasonably assured, the Company recognizes revenue as cash payments are received. The Company estimates and charges to income a provision for bad debts based on its experience with each specific customer, the amount and length of payment arrearages, and its analysis of the lessee’s overall financial condition. If the financial condition of any of the Company’s customers deteriorates, it could result in actual losses exceeding any estimated allowances. The Company had no allowance for doubtful accounts at December 31, 2014 and 2013. (k)Comprehensive (Loss)/Income The Company does not have any comprehensive income other than the revenue and expense items included in the statements of operations. As a result, comprehensive (loss)/income equals net (loss)/income for the years ended December 31, 2014 and 2013. (l)Finance Leases The lease for one of the Company’s aircraft contained a lessee purchase option at a price substantially below the asset's estimated residual value at the exercise date for the option. Consequently, the Company considered the purchase option to be a “bargain purchase option” and classified the lease as a finance lease for financial accounting purposes. The Company does not include the value, purchase price or accumulated depreciation of finance lease assets on its balance sheet. Instead, the discounted present value of (i) future minimum lease payments (including the bargain purchase option) and (ii) any residual value not subject to a bargain purchase option are reported as a finance lease receivable. Rental revenue and depreciation expense are not recognized on finance leases. Rather, the Company accrues interest on the balance of the finance lease receivable based on the interest rate inherent in the applicable lease. The aircraft that was subject to a finance lease was sold to the lessee during 2014. Two engines that were previously subject to finance leases were returned to the Company during 2014 and the finance lease receivable balances were reclassified to aircraft and aircraft engines held for lease on the Company’s balance sheet. The Company recognized interest earned on finance leases as “other income” in the amount of $150,000 and $175,700 in 2014 and 2013, respectively. (m)Recent Accounting Pronouncements On May 28, 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2014-09 (the "ASU") that created the new Topic 606 in the Accounting Standards Codification ("ASC"). The ASU also included numerous conforming additions and amendments to other Topics within the ASC. Topic 606 establishes new rules that affect the amount and timing of revenue recognition for contracts with customers, but does not affect lease accounting and reporting. As such, adoption of these provisions will not affect the Company's lease revenues but may affect the reporting of other of the Company's revenues. The provisions included in the ASU are effective for years commencing after December 15, 2016, cannot be adopted early, and may be reflected using either a full retrospective method or a simplified method that does not recast prior periods but does disclose the effect of the adoption on the current period financial statements. The Company has not determined either the potential impact on its financial statements nor the method it will elect to use in connection with the adoption of the changes included in the ASU. On August 27, 2014, the FASB issued ASU 2014-15, "Presentation of Financial Statements - Going Concern," which added Subtopic 205-40 to the ASC (the "Subtopic"). This Subtopic requires management to determine whether substantial doubt exists concerning the reporting entity's ability to continue as a going concern, in which case certain disclosures will be required. The Subtopic affects financial statement presentation but not methods of accounting, and is effective on a prospective basis for annual periods ending after December 2016 and each reporting period thereafter, although early adoption is permitted. The Company has not early adopted the Subtopic.

1.Organization and Summary of Significant Accounting Policies

(a)The Company and Basis of Presentation

AeroCentury Corp. ("the Company'), a Delaware corporation incorporated in 1997, typically acquires used regional aircraft and engines for lease to foreign and domestic regional carriers.

As discussed in Note 2, during the first quarter of 2014, the Company changed its method of accounting for non-refundable maintenance reserves and certain lessor maintenance obligations. The Company has applied this change in accounting principle retrospectively to all periods presented in accordance with ASC 250, Accounting Changes and Error Corrections (“ASC 250”).

(b)Use of Estimates

The Company’s financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable for making judgments that are not readily apparent from other sources.

The most significant estimates with regard to these financial statements are the residual values and useful lives of the assets, the amount and timing of cash flows associated with each asset that are used to evaluate whether assets are impaired, accrued maintenance costs, accounting for income taxes, and the amounts recorded as allowances for doubtful accounts.

(c)Cash and cash equivalents

The Company considers highly liquid investments readily convertible into known amounts of cash, with original maturities of 90 days or less from the date of acquisition, as cash equivalents.

(d)Aircraft Capitalization and Depreciation

The Company’s interests in aircraft and aircraft engines are recorded at cost, which includes acquisition costs. Since inception, the Company has typically purchased only used aircraft and aircraft engines. It is the Company’s policy to hold aircraft for approximately twelve years unless market conditions dictate otherwise. Therefore, depreciation of aircraft is initially computed using the straight-line method over the anticipated holding period, usually twelve years, to an estimated residual value based on appraisal. For an aircraft engine held for lease as a spare, the Company estimates the length of time that it will hold the aircraft engine based upon estimated usage, repair costs and other factors, and depreciates it to the appraised residual value over such period using the straight-line method.

The Company periodically reviews plans for lease or sale of its aircraft and aircraft engines and changes, as appropriate, the remaining expected holding period for such assets. Estimated residual values are reviewed and adjusted periodically, based upon updated estimates obtained from an independent appraiser. Decreases in the fair value of aircraft could affect not only the current value, discussed below, but also the estimated residual value.

Assets that are held for sale are not subject to depreciation and are separately classified on the balance sheet. Such assets are carried at the lower of their carrying value or estimated fair values, less costs to sell.

(e)Fair Value Measurements

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs, to the extent possible. The fair value hierarchy under GAAP is based on three levels of inputs.

Level 1 - Quoted prices in active markets for identical assets or liabilities.

Level 2 - Inputs other than Level 1 that are observable, either directly or indirectly, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis

The carrying amount of the Company's money market funds included in cash and cash equivalents was $1,044,300 and $1,842,000 at December 31, 2014 and December 31, 2013. The fair value of the Company's money market funds would be categorized as Level 1 under the GAAP fair value hierarchy.

As of December 31, 2014 and December 31, 2013, there were no liabilities that were required to be measured and recorded at fair value on a recurring basis.

Assets Measured and Recorded at Fair Value on a Nonrecurring Basis

The Company determines fair value of long-lived assets held and used, such as aircraft and aircraft engines held for lease and held for sale, by reference to independent appraisals, quoted market prices (e.g., offers to purchase) and other factors. An impairment charge is recorded when the Company believes that the carrying value of an asset will not be recovered through future net cash flows and that the carrying value exceeds its fair value.

During 2014, based on appraised values, the Company recorded impairment charges totaling $3,124,200 for two Fokker 100 aircraft and two Fokker 50 aircraft that are held for lease, resulting in a carrying value of $7,837,300. The fair value of such assets would be categorized as Level 2 under the GAAP fair value hierarchy. No impairments were recorded on the Company's aircraft and aircraft engines held for lease in 2013.

During 2014, based on management's estimate of realizable value, the Company recorded impairment charges totaling $15,612,300 for five Fokker 100 aircraft and one Fokker 50 aircraft that are held for sale, resulting in a carrying value of $6,100,000. The fair value of such assets would be categorized as Level 3 under the GAAP fair value hierarchy. No impairments were recorded on the Company's aircraft and aircraft engines held for sale in 2013.

Fair Value of Other Financial Instruments

The Company’s financial instruments, other than cash and cash equivalents, consist principally of finance leases receivable and amounts borrowed under its credit facility (the “Credit Facility,” as defined in Note 7). The fair value of accounts receivable, finance leases receivable, accounts payable and the Company’s maintenance reserves and accrued maintenance costs approximates the carrying value of these financial instruments.

Borrowings under the Company’s Credit Facility bear floating rates of interest that reset periodically to a market benchmark rate plus a credit margin. The Company believes the effective interest rate of this debt agreement approximates current market rates for such indebtedness at the balance sheet date, and therefore that the carrying amount of its floating rate debt at the balance sheet dates approximates its fair value. The fair value of the Company’s outstanding balance of its Credit Facility would be categorized as Level 3 under the GAAP fair value hierarchy.

(f)Impairment of Long-lived Assets

The Company reviews assets for impairment when there has been an event or a change in circumstances indicating that the carrying amount of a long-lived asset may not be recoverable. In addition, the Company routinely reviews all long-lived assets for impairment annually. Recoverability of an asset is measured by comparison of its carrying amount to the future estimated undiscounted cash flows (without interest charges) that the asset is expected to generate. Estimates are based on currently available market data and independent appraisals and are subject to fluctuation from time to time. If these estimated future cash flows are less than the carrying value of an asset at the time of evaluation, any impairment to be recognized is measured by the amount by which the carrying amount of the asset exceeds its fair value. Fair value is determined by reference to independent appraisals and other factors considered relevant by management. Significant management judgment is required in the forecasting of future operating results that are used in the preparation of estimated future undiscounted cash flows and, if different conditions prevail in the future, material write-downs may occur. As discussed in (e) Fair Value Measurements above, the Company recorded impairment provisions totaling $18,736,500 in 2014. No impairment provisions were recorded in 2013.

(g)Deferred Financing Costs and Commitment Fees

Costs incurred in connection with debt financing are deferred and amortized over the term of the debt using the effective interest method or, in certain instances where the differences are not material, using the straight-line method. Costs incurred in connection with the Company’s Credit Facility are deferred and amortized using the straight-line method. Commitment fees for unused funds are expensed as incurred.

(h)Security deposits

The Company’s leases are typically structured so that if any event of default occurs under a lease, the Company may apply all or a portion of the lessee’s security deposit to cure such default. If such application of the security deposit is made, the lessee typically is required to replenish and maintain the full amount of the deposit during the remaining term of the lease. All of the security deposits received by the Company are refundable to the lessee at the end of the lease upon satisfaction of all lease terms.

(i)Taxes

As part of the process of preparing the Company’s financial statements, management estimates income taxes in each of the jurisdictions in which the Company operates. This process involves estimating the Company’s current tax exposure under the most recent tax laws and assessing temporary differences resulting from differing treatment of items for tax and GAAP purposes. These differences result in deferred tax assets and liabilities, which are included in the balance sheet. Management also assesses the likelihood that the Company’s deferred tax assets will be recovered from future taxable income, and, to the extent management believes it is more likely than not that some portion or all of the deferred tax assets will not be realized, the Company establishes a valuation allowance. To the extent the Company establishes a valuation allowance or changes the allowance in a period, the Company reflects the corresponding increase or decrease within the tax provision in the statement of operations. Significant management judgment is required in determining the Company’s future taxable income for purposes of assessing the Company’s ability to realize any benefit from its deferred taxes.

The Company accrues non-income based sales, use, value added and franchise taxes as other tax expense in the statements of operations.

(j)Revenue Recognition, Accounts Receivable and Allowance for Doubtful Accounts

Revenue from leasing of aircraft assets is recognized as operating lease revenue on a straight-line basis over the terms of the applicable lease agreements. Deferred payments are recorded as accrued rent when the cash rent received is lower than the straight-line revenue recognized. Such receivables decrease over the term of the applicable leases. Interest income is recognized on finance leases based on the interest rate implicit in the lease and the outstanding balance of the lease receivable. Maintenance reserves retained by the Company at lease-end are recognized as maintenance reserves revenue.

In instances where collectability is not reasonably assured, the Company recognizes revenue as cash payments are received. The Company estimates and charges to income a provision for bad debts based on its experience with each specific customer, the amount and length of payment arrearages, and its analysis of the lessee’s overall financial condition. If the financial condition of any of the Company’s customers deteriorates, it could result in actual losses exceeding any estimated allowances.

The Company had no allowance for doubtful accounts at December 31, 2014 and 2013.

(k)Comprehensive (Loss)/Income

The Company does not have any comprehensive income other than the revenue and expense items included in the statements of operations. As a result, comprehensive (loss)/income equals net (loss)/income for the years ended December 31, 2014 and 2013.

(l)Finance Leases

The lease for one of the Company’s aircraft contained a lessee purchase option at a price substantially below the asset's estimated residual value at the exercise date for the option. Consequently, the Company considered the purchase option to be a “bargain purchase option” and classified the lease as a finance lease for financial accounting purposes. The Company does not include the value, purchase price or accumulated depreciation of finance lease assets on its balance sheet. Instead, the discounted present value of (i) future minimum lease payments (including the bargain purchase option) and (ii) any residual value not subject to a bargain purchase option are reported as a finance lease receivable. Rental revenue and depreciation expense are not recognized on finance leases. Rather, the Company accrues interest on the balance of the finance lease receivable based on the interest rate inherent in the applicable lease. The aircraft that was subject to a finance lease was sold to the lessee during 2014.

Two engines that were previously subject to finance leases were returned to the Company during 2014 and the finance lease receivable balances were reclassified to aircraft and aircraft engines held for lease on the Company’s balance sheet.

The Company recognized interest earned on finance leases as “other income” in the amount of $150,000 and $175,700 in 2014 and 2013, respectively.

(m)Recent Accounting Pronouncements

On May 28, 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2014-09 (the "ASU") that created the new Topic 606 in the Accounting Standards Codification ("ASC"). The ASU also included numerous conforming additions and amendments to other Topics within the ASC. Topic 606 establishes new rules that affect the amount and timing of revenue recognition for contracts with customers, but does not affect lease accounting and reporting. As such, adoption of these provisions will not affect the Company's lease revenues but may affect the reporting of other of the Company's revenues. The provisions included in the ASU are effective for years commencing after December 15, 2016, cannot be adopted early, and may be reflected using either a full retrospective method or a simplified method that does not recast prior periods but does disclose the effect of the adoption on the current period financial statements. The Company has not determined either the potential impact on its financial statements nor the method it will elect to use in connection with the adoption of the changes included in the ASU.

On August 27, 2014, the FASB issued ASU 2014-15, "Presentation of Financial Statements - Going Concern," which added Subtopic 205-40 to the ASC (the "Subtopic"). This Subtopic requires management to determine whether substantial doubt exists concerning the reporting entity's ability to continue as a going concern, in which case certain disclosures will be required. The Subtopic affects financial statement presentation but not methods of accounting, and is effective on a prospective basis for annual periods ending after December 2016 and each reporting period thereafter, although early adoption is permitted. The Company has not early adopted the Subtopic.