Debt Obligations - Additional Information (Details)	1 Months Ended			12 Months Ended
	Dec. 31, 2023 USD ($)	Oct. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) tranche	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) tranche
Long Term Debt [Line Items]
Gross amount of debt	$ 1,827,059,000		$ 1,862,089,000	$ 1,827,059,000	$ 1,862,089,000
Gain on debt extinguishment				0	2,558,000
Repayments of long-term debt				665,480,000	228,840,000
WEST V
Long Term Debt [Line Items]
Fixed rate (as a percent)		8.00%
Notes issue price, percentage of par		98.84814%
Revolving credit facility
Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 500,000,000
Repayments of debt	292,000,000
Revolving credit facility | Maturity in March 2024
Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	49,800,000			49,800,000
Revolving credit facility | Maturity in June 2024
Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	158,200,000			158,200,000
WEST VI Notes | WEST VI
Long Term Debt [Line Items]
Debt instrument, face amount		$ 410,000,000
WEST VI Series A Notes
Long Term Debt [Line Items]
Gross amount of debt	$ 252,986,000		262,779,000	$ 252,986,000	262,779,000
Fixed rate (as a percent)	3.10%			3.10%
WEST VI Series B Notes
Long Term Debt [Line Items]
Gross amount of debt	$ 35,142,000		36,502,000	$ 35,142,000	36,502,000
Fixed rate (as a percent)	5.44%			5.44%
WEST VI Series C Notes
Long Term Debt [Line Items]
Gross amount of debt	$ 12,361,000		14,738,000	$ 12,361,000	$ 14,738,000
Fixed rate (as a percent)	7.39%			7.39%
ABS Notes
Long Term Debt [Line Items]
Gain on debt extinguishment			$ 2,600,000
Number of tranches of notes repurchased | tranche			6		6
Repayments of long-term debt			$ 12,200,000
Note payable at a fixed rate of interest of 4.23%, maturing in July 2031, secured by an engine
Long Term Debt [Line Items]
Gross amount of debt	$ 17,802,000		0	$ 17,802,000	$ 0
Option to repurchase amount	$ 17,000,000			$ 17,000,000
Fixed rate (as a percent)	4.23%			4.23%
Note payable at a fixed rate of interest of 4.59%, maturing in January 2032, secured by an engine
Long Term Debt [Line Items]
Gross amount of debt	$ 22,610,000		0	$ 22,610,000	0
Option to repurchase amount	$ 17,700,000			$ 17,700,000
Fixed rate (as a percent)	4.59%			4.59%
Revolving credit facility | Revolving credit facility
Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 708,000,000			$ 708,000,000
Line of credit facility, remaining borrowing capacity	$ 355,000,000		$ 273,000,000	$ 355,000,000	$ 273,000,000