Investments - Summarized Financial Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Income Statement [Abstract]
Revenue		$ 78,075	$ 66,472	$ 146,892	$ 127,597
Expenses		68,590	67,646	162,512	129,943
Income (loss) from operations		9,485	(1,174)	(15,620)	(2,346)
Statement of Financial Position [Abstract]
Total assets	[1]	2,396,383		2,396,383			$ 2,462,927
Total liabilities	[2]	1,971,642		1,971,642			2,037,237
Total shareholders’ equity		374,894	368,689	374,894	368,689	$ 371,007	375,885	$ 372,412	$ 364,015
WMES
Income Statement [Abstract]
Revenue		21,185	4,885	30,726	9,646
Expenses		17,687	6,606	32,690	12,775
Income (loss) from operations		3,498	$ (1,721)	(1,964)	$ (3,129)
Statement of Financial Position [Abstract]
Total assets		285,114		285,114			310,260
Total liabilities		202,735		202,735			225,917
Total shareholders’ equity		$ 82,379		$ 82,379			$ 84,343

[1] Total assets at June 30, 2022 and December 31, 2021, respectively, include the following assets of variable interest entities (“VIEs”) that can only be used to settle the liabilities of the VIEs: Restricted cash $60,982 and $81,312; Equipment $1,205,623 and $1,226,395; Maintenance Rights $5,433 and $5,433; Inventory $0 and $4,367; Notes receivable $81,621 and $90,868; and Other assets $5,519 and $4,775, respectively.

[2] Total liabilities at June 30, 2022 and December 31, 2021, respectively, include the following liabilities of VIEs for which the VIEs’ creditors do not have recourse to Willis Lease Finance Corporation: Debt obligations $1,160,849 and $1,197,922, respectively.