Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash inflow from amounts received from issuance of long-term debt that is wholly or partially secured by collateral. Excludes proceeds from tax exempt secured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3255-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

Name:	us-gaap_ProceedsFromIssuanceOfSecuredDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount after depreciation of long-lived, physical assets used to produce goods and services and not intended for resale, classified as other.

+ References

No definition available.

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentOtherNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

+ References

+ Details

Name:	us-gaap_RestrictedCashAndCashEquivalentsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Debt (Narrative) (Details) - USD ($) $ in Thousands		6 Months Ended
Debt (Narrative) (Details) - USD ($) $ in Thousands	Jul. 06, 2017	Jun. 30, 2017	Dec. 31, 2016	Jan. 30, 2015
Debt Instrument [Line Items]
Net book value		$ 1,864,337	$ 1,807,010
Restricted cash		5,683	6,192
Railcars [Member]
Debt Instrument [Line Items]
Net book value		379,500
Variable Interest Entity, Primary Beneficiary [Member]
Debt Instrument [Line Items]
Net book value		57,697	$ 62,477
Variable Interest Entity, Primary Beneficiary [Member] \| Containers [Member]
Debt Instrument [Line Items]
Net book value		$ 65,900
Revolving Credit Facility [Member] \| CAI Rail [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Oct. 22, 2020
Average interest rate		2.90%	2.40%
Revolving Credit Facility [Member] \| Consortium of Banks [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Mar. 15, 2020
Maximum credit commitment		$ 960,000		$ 775,000
Available borrowing capacity		688,400
Letters of credit outstanding		$ 100
Average interest rate		2.90%	2.50%
Revolving Credit Facility [Member] \| CAI International GmbH [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Sep. 01, 2020
Average interest rate		2.00%
Term Loan [Member] \| CAI Rail [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Dec. 22, 2020
Average interest rate		3.40%	3.40%
Term Loan [Member] \| Development Bank of Japan [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Apr. 30, 2018
Average interest rate		3.20%	2.90%
Term Loan [Member] \| Consortium of Banks, Note Dated October 1, 2014 [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Oct. 01, 2019
Average interest rate		2.80%	2.30%
Term Loan [Member] \| Consortium of Banks, Note Dated April 11, 2012 [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Jun. 30, 2021
Average interest rate		3.00%	2.50%
Term Loan [Member] \| Consortium Of Banks Note Dated August 30 2016 [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Aug. 01, 2021
Average interest rate		3.60%	3.60%
Term Loan [Member] \| Variable Interest Entity, Primary Beneficiary [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Jun. 01, 2019
Long-term debt		$ 4,700
Average interest rate		2.70%	2.50%
Senior Secured Notes [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Sep. 13, 2022
Average interest rate		4.90%	4.90%
Asset Backed Notes [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Mar. 01, 2028
Average interest rate		3.40%	3.40%
Collateralized Financing Obligations [Member]
Debt Instrument [Line Items]
Debt instrument maturity date		Sep. 01, 2019
Long-term debt		$ 84,400
Average interest rate		1.20%	1.10%
Subsequent Event [Member] \| Asset Backed Notes [Member] \| Class A Asset-Backed Notes [Member]
Debt Instrument [Line Items]
Proceeds from asset backed notes	$ 240,900
Average interest rate	3.60%
Subsequent Event [Member] \| Asset Backed Notes [Member] \| Class B Asset-Backed Notes [Member]
Debt Instrument [Line Items]
Proceeds from asset backed notes	$ 12,200
Average interest rate	4.60%