Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Entity Listings [Line Items]
Entity Registrant Name	CAI International, Inc.
Entity Filer Category	Accelerated Filer
Entity Central Index Key	0001388430
Amendment Flag	false
Document Type	10-Q
Document Fiscal Period Focus	Q3
Trading Symbol	CAI
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		17,425,754
Entity Emerging Growth Company	false
Entity Small Business	false
Entity File Number	001-33388
Entity Address, Address Line One	Steuart Tower, 1 Market Plaza, Suite 2400
Entity Address, City or Town	San Francisco
Entity Address, Postal Zip Code	94105
Entity Address, State or Province	CA
City Area Code	415
Local Phone Number	788-0100
Series A Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Stock [Member]
Entity Listings [Line Items]
Trading Symbol	CAI-PA
Series B Fixed-to-Floating Rate Cumulative Redeemable Perpetual Preferred Stock [Member]
Entity Listings [Line Items]
Trading Symbol	CAI-PB