Debt instrument fixed charge coverage ratio.

No definition available.

Name:	gfn_DebtInstrumentFixedChargeCoverageRatio
Namespace Prefix:	gfn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument Prepayment Penalty Percentage

+ References

No definition available.

+ Details

Name:	gfn_DebtInstrumentPrepaymentPenaltyPercentage
Namespace Prefix:	gfn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt instrument redemption charge.

+ References

No definition available.

+ Details

Name:	gfn_DebtInstrumentRedemptionCharge
Namespace Prefix:	gfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Inter company dividends.

+ References

No definition available.

+ Details

Name:	gfn_InterCompanyDividends
Namespace Prefix:	gfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line Of Credit Facility Additional Increase In Maximum Borrowing Capacity

+ References

No definition available.

+ Details

Name:	gfn_LineOfCreditFacilityAdditionalIncreaseInMaximumBorrowingCapacity
Namespace Prefix:	gfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line Of Credit Financing Fees

+ References

No definition available.

+ Details

Name:	gfn_LineOfCreditFinancingFees
Namespace Prefix:	gfn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The rate of unused commitment fee percentage.

+ References

No definition available.

+ Details

Name:	gfn_UnusedCommitmentFeePercentage
Namespace Prefix:	gfn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 45
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=118262064&loc=SL116631418-115840

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 45
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=118262064&loc=SL116631419-115840

+ Details

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

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

+ Details

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

- Definition

Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6897108&loc=SL6897125-166521

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6450520&loc=d3e32618-110901

+ Details

Name:	us-gaap_ForeignCurrencyExchangeRateTranslation1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120398452&loc=d3e534808-122878

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120400017&loc=d3e572229-122910

+ Details

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

- 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

- Details

Name:	srt_CurrencyAxis=currency_AUD
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CurrencyAxis=currency_NZD
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=gfn_WellsFargoCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=gfn_PacVanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_SeriesCPreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementGeographicalAxis=srt_NorthAmericaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=gfn_SeniorSecuredRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gfn_AustraliaAndNewZealandBankingGroupLimitedAndCommonwealthBankOfAustraliaCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gfn_DeutscheBankCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gfn_DeutscheBankCreditFacilityAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gfn_DeutscheBankCreditFacilityBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gfn_DeutscheBankCreditFacilityCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=gfn_DeutscheBankCreditFacilityDMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Senior and Other Debt - ANZ/CBA Credit Facility and North America Leasing Senior Credit Facility - Additional Information (Details)	3 Months Ended
	Sep. 30, 2020 AUD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 USD ($)
Australian Dollar
Senior and Other Debt
Foreign currency exchange rate, translation	0.714131		0.714131
New Zealand Dollar
Senior and Other Debt
Foreign currency exchange rate, translation	0.660034		0.660034
Wells Fargo Credit Facility
Senior and Other Debt
Payment of intercompany dividends from Pac-Van and Lone Star		$ 5,000,000
Pac-Van \| Wells Fargo Credit Facility
Senior and Other Debt
Borrowings under credit facility			$ 163,779,000
Availability under ANZ credit facility			$ 96,357,000
Maximum \| Wells Fargo Credit Facility
Senior and Other Debt
Unused commitment fee percentage	0.375%	0.375%
Minimum \| Wells Fargo Credit Facility
Senior and Other Debt
Fixed charge coverage ratio	1.25		1.25
Unused commitment fee percentage	0.25%	0.25%
Series C Preferred Stock \| Wells Fargo Credit Facility
Senior and Other Debt
Payment of intercompany dividends from Pac-Van and Lone Star		$ 5,000,000
North America \| Senior Secured Revolving Credit Facility
Senior and Other Debt
Line of credit facility maximum borrowing capacity			$ 285,000,000
North America \| Wells Fargo Credit Facility
Senior and Other Debt
Line of Credit Facility Additional Increase in Maximum Borrowing Capacity		25,000,000
Unsecured senior notes \| Wells Fargo Credit Facility
Senior and Other Debt
Payment of intercompany dividends from Pac-Van and Lone Star		$ 6,300,000
Base Rate \| Wells Fargo Credit Facility
Senior and Other Debt
Interest rate	0.50%	0.50%
Base Rate \| Maximum \| Wells Fargo Credit Facility
Senior and Other Debt
Interest rate	1.50%	1.50%
Base Rate \| Minimum \| Wells Fargo Credit Facility
Senior and Other Debt
Interest rate	1.00%	1.00%
LIBOR \| Wells Fargo Credit Facility
Senior and Other Debt
Interest rate	0.50%	0.50%
LIBOR \| Maximum \| Wells Fargo Credit Facility
Senior and Other Debt
Interest rate	3.00%	3.00%
LIBOR \| Minimum \| Wells Fargo Credit Facility
Senior and Other Debt
Interest rate	2.50%	2.50%
ANZ/CBA Credit Facility
Senior and Other Debt
Line of credit facility maximum borrowing capacity	$ 150,000,000
Deutsche Bank Credit Facility
Senior and Other Debt
Borrowings under credit facility	174,626,000		124,705,000
Debt instrument, financing fees	2,871,400	$ 2,050,600
Debt instrument, fee	1,051,600	$ 751,000
Cash available at bank	44,225,000		31,582,000
Deferred financing cost	$ 97,000		70,000
Deutsche Bank Credit Facility \| Maximum
Senior and Other Debt
Debt instrument, prepayment penalties percentage	1.00%	1.00%
Interest rate	5.50%	5.50%
Deutsche Bank Credit Facility \| Minimum
Senior and Other Debt
Interest rate	4.25%	4.25%
Deutsche Bank Credit Facility A
Senior and Other Debt
Borrowings under credit facility	$ 43,000,000		30,707,600
Deutsche Bank Credit Facility B
Senior and Other Debt
Borrowings under credit facility	116,500,000		83,196,300
Deutsche Bank Credit Facility C
Senior and Other Debt
Borrowings under credit facility	20,000,000		14,282,600
Deutsche Bank Credit Facility D
Senior and Other Debt
Borrowings under credit facility	$ 37,500,000		$ 26,779,900