2.4.0.81020 - Disclosure - Management Estimatestruefalsefalse1false falsefalseD2013Q2YTDhttp://www.sec.gov/CIK0001018164duration2013-01-01T00:00:002013-06-30T00:00:001true 1us-gaap_ChangeInAccountingEstimateAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Management Estimates2false 2us-gaap_AccountingChangesAndErrorCorrectionsTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-size:10.0pt;font-family:Times New Roman;"> 2.  Management Estimates   These consolidated financial statements have been prepared on the accrual basis of accounting in accordance with accounting principles generally accepted in the United States.   The preparation of consolidated financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. On an ongoing basis, we evaluate our estimates, including those related to residual values, estimated asset lives, impairments and bad debts. We base our estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.   Management believes that the accounting policies on revenue recognition, maintenance reserves and expenditures, useful life of equipment, asset residual values, asset impairment and allowance for doubtful accounts are critical to the results of operations.   If the useful lives or residual values are lower than those estimated by us, upon sale of the asset a loss may be realized. Significant management judgment is required in the forecasting of future operating results, which are used in the preparation of projected undiscounted cash-flows and should different conditions prevail, material impairment write-downs may occur. </div>falsefalsefalsenonnum:textBlockItemTypenaThe entire disclosure for reporting accounting changes and error corrections. It includes the conveyance of information necessary for a user of the Company's financial information to understand all aspects and required disclosure information concerning all changes and error corrections reported in the Company's financial statements for the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6801783&loc=d3e22644-107794 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 45 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=6368906&loc=d3e21914-107793 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6801783&loc=d3e22595-107794 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6801783&loc=d3e22499-107794 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 1.N.Q3) -URI http://asc.fasb.org/extlink&oid=6369664&loc=d3e30840-122693 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 1 -Section N Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 154 -Paragraph 17, 22, 25, 26 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Management EstimatesfalseManagement EstimatesUnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.willislease.com/role/DisclosureManagementEstimates12