Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
REVENUE
Lease rent revenue									$ 190,690	$ 175,609
Maintenance reserve revenue									108,998	87,009
Spare parts and equipment sales									74,651	71,141
Gain on sale of leased equipment									20,044	6,944
Other revenue									14,777	7,644
Total revenue	$ 89,228	$ 120,366	$ 95,797	$ 103,769	$ 118,190	$ 80,958	$ 78,702	$ 70,497	409,160	348,347
EXPENSES
Depreciation and amortization expense									86,236	76,814
Cost of spare parts and equipment sales									62,647	61,025
Write-down of equipment									18,220	10,651
General and administrative									86,523	72,021
Technical expense									8,122	11,142
Net finance costs:
Interest expense									66,889	64,220
Loss on debt extinguishment									220	0
Total expenses									67,109	64,220
Total expenses									328,857	295,873
Earnings from operations									80,303	52,474
Earnings from joint ventures									8,578	3,800
Income before income taxes									88,881	56,274
Income tax expense									21,959	13,043
Net income									66,922	43,231
Preferred stock dividends									3,250	3,250
Accretion of preferred stock issuance costs									84	83
Net income attributable to common shareholders	$ 4,156	$ 23,232	$ 16,144	$ 20,056	$ 17,274	$ 8,834	$ 7,528	$ 6,261	$ 63,588	$ 39,898
Basic weighted average earnings per common share (in dollars per share)	$ 0.71	$ 3.97	$ 2.75	$ 3.47	$ 2.99	$ 1.50	$ 1.28	$ 1.03	$ 10.90	$ 6.75
Diluted weighted average earnings per common share (in dollars per share)	$ 0.68	$ 3.81	$ 2.66	$ 3.35	$ 2.91	$ 1.47	$ 1.26	$ 1.00	$ 10.50	$ 6.60
Basic weighted average common shares outstanding (in shares)	5,850	5,847	5,866	5,779	5,782	5,900	5,878	6,104	5,836	5,915
Diluted weighted average common shares outstanding (in shares)	6,099	6,094	6,061	5,978	5,939	6,004	5,991	6,256	6,058	6,046