XML 78 R62.htm IDEA: XBRL DOCUMENT v3.20.4

Debt Obligations - Narrative (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) engine	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020	Mar. 31, 2020 engine	Mar. 31, 2020 airframe	Jul. 31, 2019	Jun. 30, 2019 USD ($)	Feb. 28, 2019 USD ($)	Dec. 31, 2018 USD ($)
Long Term Debt [Line Items]
Loss on extinguishment of debt		$ 4,688,000	$ 220,000
Long-term debt outstanding		$ 1,712,886,000	1,270,469,000
WEST V
Long Term Debt [Line Items]
Number of assets used to secure debt						54	3
WEST V | Assets Under Purchase Agreement With WEST V [Member]
Long Term Debt [Line Items]
Number of assets used to secure debt						25	3
WEST V Notes | WEST V
Long Term Debt [Line Items]
Debt instrument, face amount				$ 366,200,000
WEST V Series A Notes
Long Term Debt [Line Items]
Fixed rate		3.23%
Long-term debt outstanding		$ 286,863,000	0
WEST V Series A Notes | WEST V
Long Term Debt [Line Items]
Debt instrument, face amount				303,000,000.0
Fixed rate					3.228%
Debt term	8 years
Notes issue price, percentage of par	99.99859%
WEST V Series B Notes
Long Term Debt [Line Items]
Fixed rate		4.21%
Long-term debt outstanding		$ 39,855,000	0
WEST V Series B Notes | WEST V
Long Term Debt [Line Items]
Debt instrument, face amount				42,100,000
Fixed rate					4.212%
Debt term	8 years
Notes issue price, percentage of par	99.99493%
WEST V Series C Notes
Long Term Debt [Line Items]
Fixed rate		6.66%
Long-term debt outstanding		$ 19,043,000	0
WEST V Series C Notes | WEST V
Long Term Debt [Line Items]
Debt instrument, face amount				$ 21,100,000
Fixed rate					6.657%
Debt term	8 years
Notes issue price, percentage of par	99.99918%
WEST II Notes
Long Term Debt [Line Items]
Loss on extinguishment of debt	$ 4,700,000
Note payable at a fixed rate of interest of 3.18%, maturing in July 2024, secured by an aircraft
Long Term Debt [Line Items]
Fixed rate		3.18%
Long-term debt outstanding		$ 7,247,000	9,124,000
Note payable due July 2022
Long Term Debt [Line Items]
Number of assets used to secure debt | engine		2
Long-term debt outstanding		$ 6,138,000	7,286,000							$ 8,100,000
Maximum | Note payable at a fixed rate of interest of 3.18%, maturing in July 2024, secured by an aircraft
Long Term Debt [Line Items]
Fixed rate								3.18%
LIBOR | Revolving credit facility
Long Term Debt [Line Items]
Variable rate spread		1.38%
LIBOR | Minimum | Note payable due July 2022
Long Term Debt [Line Items]
Variable rate spread		1.85%
LIBOR | Maximum | Note payable due July 2022
Long Term Debt [Line Items]
Variable rate spread		2.50%
Revolving credit facility | Revolving credit facility
Long Term Debt [Line Items]
Line of credit facility maximum borrowing Capacity before amendment											$ 890,000,000.0
Line of credit facility, maximum borrowing capacity									$ 1,000,000,000.0
Line of credit facility, maximum borrowing capacity under accordion feature		$ 1,300,000,000
Debt issuance costs, line of credit									$ 2,800,000
Loss on extinguishment of debt		200,000
Line of credit facility, remaining borrowing capacity		$ 223,000,000.0	$ 603,000,000.0

X

- 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

X

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870

Reference 2: 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

Reference 3: 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 4: 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

+ Details

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

X

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

X

- Definition

Contractual interest rate for funds borrowed, under the debt 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- 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

X

- Definition

Amount, before accumulated amortization, of debt issuance costs related to line of credit arrangements. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section S45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68176171&loc=SL68176184-208336

+ Details

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

X

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12355-112629

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117329964&loc=d3e12317-112629

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

Name:	us-gaap_GainsLossesOnExtinguishmentOfDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for a specific purpose other than for financing goods acquired for inventory or imminent delivery to a customer.

+ References

No definition available.

+ Details

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

X

- 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

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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- Definition

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

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

X

- Definition

Period between issuance and maturity of long-term debt, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

Name:	us-gaap_LongTermDebtTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Represents the maximum borrowing capacity under the credit facility before the amendment.

+ References

No definition available.

+ Details

Name:	wlfc_LineOfCreditFacilityMaximumBorrowingCapacityBeforeAmendment
Namespace Prefix:	wlfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Notes issues at price as percentage of par.

+ References

No definition available.

+ Details

Name:	wlfc_NotesIssuePricePercentageOfPar
Namespace Prefix:	wlfc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Number Of Assets Used To Secure Debt

+ References

No definition available.

+ Details

Name:	wlfc_NumberOfAssetsUsedToSecureDebt
Namespace Prefix:	wlfc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=wlfc_WESTVMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_LongLivedAssetsHeldForSaleByAssetTypeAxis=wlfc_AssetsUnderPurchaseAgreementWithWESTVMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_WESTVNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_WESTVSeriesANotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_WESTVSeriesBNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_WESTVSeriesCNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_Class2012ATermNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_NotesPayableDueJuly2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_NotesPayableDueJuly2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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

X

- Details

Name:	us-gaap_DebtInstrumentAxis=wlfc_SecuredCreditFacilityDueApril2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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

X

- Details

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