Debt Obligations - Schedule of Notes Payable (Details)	6 Months Ended
	Jun. 30, 2023 USD ($) airframe	Dec. 31, 2022 USD ($)
Long Term Debt
Gross amount of debt	$ 1,839,706,000	$ 1,862,089,000
Less: unamortized debt issuance costs	(12,685,000)	(14,811,000)
Total debt obligations	1,827,021,000	1,847,278,000
Credit facility at a floating rate of interest of one-month London Interbank Offered Rate (“LIBOR”) plus 1.75% at June 30, 2023, secured by engines. The facility has a committed amount of $1.0 billion at June 30, 2023, which revolves until the maturity date of June 2024
Long Term Debt
Line of credit facility outstanding amount	$ 758,000,000	727,000,000
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	$ 257,726,000	262,779,000
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	$ 35,800,000	36,502,000
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	$ 13,537,000	14,738,000
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	$ 248,375,000	255,136,000
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	$ 34,600,000	35,542,000
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	$ 12,036,000	13,314,000
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	$ 226,932,000	238,072,000
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	$ 31,216,000	36,386,000
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	$ 188,951,000	209,061,000
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	$ 30,255,000	30,255,000
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	$ 2,278,000	$ 3,304,000
Revolving credit facility | Credit facility at a floating rate of interest of one-month London Interbank Offered Rate (“LIBOR”) plus 1.75% at June 30, 2023, secured by engines. The facility has a committed amount of $1.0 billion at June 30, 2023, 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 London Interbank Offered Rate (“LIBOR”) plus 1.75% at June 30, 2023, secured by engines. The facility has a committed amount of $1.0 billion at June 30, 2023, which revolves until the maturity date of June 2024
Long Term Debt
Variable rate (as a percent)	1.75%