Description of Business and Significant Accounting Policies (Policy)	3 Months Ended
	Mar. 31, 2020
Description of Business and Significant Accounting Policies [Abstract]
Organization	Organization CAI International, Inc., together with its subsidiaries (collectively, CAI or the Company), is a transportation finance and logistics company. The Company purchases equipment, primarily intermodal shipping containers and railcars, which it leases to its customers. The Company also manages equipment for third-party investors. In operating its fleet, the Company leases, re-leases and disposes of equipment and contracts for the repair, repositioning and storage of equipment. The Company also provides domestic and international logistics services. The Company’s common stock, 8.50% Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Stock and 8.50% Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Stock are traded on the New York Stock Exchange under the symbols “CAI,” “CAI-PA” and “CAI-PB,” respectively. The Company’s corporate headquarters are located in San Francisco, California.
Basis Of Presentation	Basis of Presentation The accompanying unaudited consolidated financial statements include the financial statements of CAI International, Inc. and its wholly-owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, the accompanying unaudited consolidated financial statements contain all normal, recurring adjustments necessary to present fairly the Company’s financial position as of March 31, 2020 and December 31, 2019, the Company’s results of operations for the three months ended March 31, 2020 and 2019, and the Company’s cash flows for the three months ended March 31, 2020 and 2019. Certain reclassifications have been made to prior year financial statements to conform to the current presentation. The results of operations and cash flows for the periods presented are not necessarily indicative of the results of operations or cash flows which may be reported for the remainder of 2020 or in any future period. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) have been condensed or omitted. The accompanying unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2019, included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on March 5, 2020. Due to market conditions, the Company decided during the three months ended March 31, 2020 to terminate the sale process for its rail business. As a result, the railcar assets have been reclassified as held for use as of March 31, 2020 and the rail business reclassified as a continuing operation. All prior periods presented in the unaudited consolidated financial statements have been restated to reflect the reclassification. See Note 3 – Rental Equipment for further information over the reclassification of the railcar assets as held for use.
Concentration Of Credit Risk	Concentration of Credit Risk The Company’s equipment leases and trade receivables subject it to potential credit risk. The Company extends credit to its customers based upon an evaluation of each customer’s financial condition and credit history. Evaluations of the financial condition and associated credit risk of customers are performed an on ongoing basis. The Company’s largest customer accounted for 13% of the Company’s total billings during the three months ended March 31, 2020.
Accounting Policy Updates	Accounting Policy Updates Recently Adopted Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326) (ASU 2016-13) and subsequently issued amendments. The guidance affects the Company’s net investment in finance leases, financing receivable and accounts receivable for sales of rental equipment and logistics operations. Topic 326 requires the measurement of expected credit losses to be based on relevant information from past events, including historical experiences, current conditions and reasonable and supportable forecasts that affect collectability. The Company adopted ASU 2016-13 effective January 1, 2020, using the modified retrospective method, which did not have a significant impact on the consolidated financial statements as credit losses are not expected to be significant based on historical loss trends, the financial condition of customers, and external market factors. Allowance for credit losses – Net investment in finance leases and financing receivable The allowance for credit losses on net investment in finance leases and financing receivable is estimated on a collective basis by internal customer rating (see Note 4 – Net investment in finance leases for descriptions of ratings). Expected credit losses for these financial assets are estimated using a loss-rate methodology which considers historical credit loss information that is adjusted for current conditions and reasonable and supportable forecasts. Except as described above, there were no changes to the Company’s accounting policies during the three months ended March 31, 2020. See Note 2 to the audited consolidated financial statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2019, filed with the SEC on March 5, 2020, for a description of the Company’s significant accounting policies.