Debt Obligations - Schedule of Notes Payable (Details)	3 Months Ended
Mar. 31, 2022 USD ($) airframe	Dec. 31, 2021 USD ($)
Long Term Debt
Gross amount of debt	$ 1,777,363,000	$ 1,809,620,000
Less: unamortized debt issuance costs	(18,237,000)	(19,356,000)
Total debt obligations	1,759,126,000	1,790,264,000
Credit facility at a floating rate of interest of one-month LIBOR plus 1.375% at March 31, 2022, secured by engines. The facility has a committed amount of $1.0 billion at March 31, 2022, which revolves until the maturity date of June 2024
Long Term Debt
Line of credit facility outstanding amount	$ 580,000,000	590,000,000
WEST VI Series A 2021 term notes payable at a fixed rate of interest of 3.10%, maturing in May 2046, secured by engines and one airframe
Long Term Debt
Fixed rate (as a percent)	3.10%
Number of assets used to secure debt \| airframe	1
Gross amount of debt	$ 271,544,000	273,723,000
WEST VI Series B 2021 term notes payable at a fixed rate of interest of 5.44%, maturing in May 2046, secured by engines and one airframe
Long Term Debt
Fixed rate (as a percent)	5.44%
Number of assets used to secure debt \| airframe	1
Gross amount of debt	$ 37,720,000	38,022,000
WEST VI Series C 2021 term notes payable at a fixed rate of interest of 7.39%, maturing in May 2046, secured by engines and one airframe
Long Term Debt
Fixed rate (as a percent)	7.39%
Number of assets used to secure debt \| airframe	1
Gross amount of debt	$ 17,535,000	18,158,000
WEST V Series A 2020 term notes payable at a fixed rate of interest of 3.23%, maturing in March 2045, secured by engines
Long Term Debt
Fixed rate (as a percent)	3.23%
Gross amount of debt	$ 266,784,000	272,909,000
WEST V Series B 2020 term notes payable at a fixed rate of interest of 4.21%, maturing in March 2045, secured by engines
Long Term Debt
Fixed rate (as a percent)	4.21%
Gross amount of debt	$ 37,066,000	38,004,000
WEST V Series C 2020 term notes payable at a fixed rate of interest of 6.66%, maturing in March 2045, secured by engines
Long Term Debt
Fixed rate (as a percent)	6.66%
Gross amount of debt	$ 15,282,000	16,342,000
WEST IV Series A 2018 term notes payable at a fixed rate of interest of 4.75%, maturing in September 2043, secured by engines
Long Term Debt
Fixed rate (as a percent)	4.75%
Gross amount of debt	$ 254,366,000	262,260,000
WEST IV Series B 2018 term notes payable at a fixed rate of interest of 5.44%, maturing in September 2043, secured by engines
Long Term Debt
Fixed rate (as a percent)	5.44%
Gross amount of debt	$ 38,885,000	38,885,000
WEST III Series A 2017 term notes payable at a fixed rate of interest of 4.69%, maturing in August 2042, secured by engines
Long Term Debt
Fixed rate (as a percent)	4.69%
Gross amount of debt	$ 221,174,000	223,815,000
WEST III Series B 2017 term notes payable at a fixed rate of interest of 6.36%, maturing in August 2042, secured by engines
Long Term Debt
Fixed rate (as a percent)	6.36%
Gross amount of debt	$ 32,195,000	32,195,000
Note payable at a fixed rate of interest of 3.18%, maturing in July 2024, secured by an aircraft
Long Term Debt
Fixed rate (as a percent)	3.18%
Gross amount of debt	$ 4,812,000	$ 5,307,000
Revolving credit facility \| Credit facility at a floating rate of interest of one-month LIBOR plus 1.375% at March 31, 2022, secured by engines. The facility has a committed amount of $1.0 billion at March 31, 2022, which revolves until the maturity date of June 2024
Long Term Debt
Line of credit facility, maximum borrowing capacity	$ 1,000,000,000.0
LIBOR \| Credit facility at a floating rate of interest of one-month LIBOR plus 1.375% at March 31, 2022, secured by engines. The facility has a committed amount of $1.0 billion at March 31, 2022, which revolves until the maturity date of June 2024
Long Term Debt
Variable rate (as a percent)	1.375%

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

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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.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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.

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

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