Investments (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) engine aircraft.	Dec. 31, 2018 USD ($)	Dec. 31, 2014	Dec. 31, 2011
Investments
Ownership interest	50.00%
Net book value of equipment held for operating lease	$ 1,650,918	$ 1,673,135
Investment in WMES joint ventures at beginning of the period	47,941	50,641
Earnings (loss) from joint ventures	8,578	3,800
Contribution	5,713	0
Distribution	(3,300)	(5,730)
Foreign currency translation adjustment	222	770
Other comprehensive loss from joint ventures	(774)	0
Investment in WMES joint ventures at end of the period	57,936	47,941
Other revenue	$ 14,777	7,644
WMES
Investments
Ownership interest	100.00%			50.00%
Number of engines in lease portfolio | engine	36
Number of aircraft in lease portfolio | aircraft.	5
Net book value of equipment held for operating lease	$ 306,000
Investment in WMES joint ventures at beginning of the period	34,183	36,014
Earnings (loss) from joint ventures	8,312	3,899
Contribution	5,713
Distribution	(3,300)	(5,730)
Foreign currency translation adjustment	0	0
Other comprehensive loss from joint ventures	(774)
Investment in WMES joint ventures at end of the period	44,134	34,183
Consolidated Statements of Income
Revenue	55,770	38,465
Expenses	41,253	30,934
WMES net income	14,517	7,531
Consolidated Balance Sheets
Total assets	322,606	274,744
Total liabilities	227,052	198,534
Total WMES net equity	$ 95,554	76,210
CASC Willis
Investments
Ownership interest			50.00%
Number of engines in lease portfolio | engine	4
Net book value of equipment held for operating lease	$ 49,200
Investment in WMES joint ventures at beginning of the period	13,758	14,627
Earnings (loss) from joint ventures	266	(99)
Contribution	0
Distribution	0	0
Foreign currency translation adjustment	222	770
Other comprehensive loss from joint ventures	0
Investment in WMES joint ventures at end of the period	$ 13,802	$ 13,758