Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
REVENUE
Lease rent revenue													$ 119,895	$ 108,046	$ 101,431
Maintenance reserve revenue													57,091	53,396	53,322
Spare parts and equipment sales													17,783	25,582	8,917
Gain on sale of leased equipment													3,482	8,320	5,882
Other revenue													9,023	2,718	4,506
Total revenue	$ 55,476	$ 51,461	$ 49,618	$ 50,719	$ 55,186	$ 57,730	$ 43,810	$ 41,336	$ 41,205	$ 45,519	$ 43,994	$ 43,340	207,274	198,062	174,058
EXPENSES
Depreciation and amortization expense													66,280	69,424	65,314
Cost of spare parts and equipment sales													13,293	17,849	7,474
Write-down of equipment													9,514	9,181	5,602
General and administrative													47,780	42,744	35,859
Technical expense													6,993	9,403	12,336
Net finance costs:
Interest expense													41,144	39,012	37,062
Loss (gain) on debt extinguishment													137	(1,151)
Total net finance costs													41,281	37,861	37,062
Total expenses													185,141	186,462	163,647
Earnings from operations													22,133	11,600	10,411
Earnings from joint ventures													1,813	1,175	1,329
Income before income taxes													23,946	12,775	11,740
Income tax expense													9,877	6,315	4,560
Net income													14,069	6,460	7,180
Preferred stock dividends													281
Accretion of preferred stock issuance costs													8
Net income attributable to common shareholders	$ 2,418	$ 3,985	$ 3,366	$ 4,011	$ 3,037	$ 2,551	$ (486)	$ 1,358	$ (491)	$ 1,000	$ 2,319	$ 4,352	$ 13,780	$ 6,460	$ 7,180
Basic earnings per common share: (in dollars per share)	$ 0.40	$ 0.63	$ 0.50	$ 0.57	$ 0.39	$ 0.33	$ (0.06)	$ 0.17	$ (0.06)	$ 0.13	$ 0.29	$ 0.55	$ 2.10	$ 0.83	$ 0.91
Diluted earnings per common share: (in dollars per share)	$ 0.39	$ 0.62	$ 0.49	$ 0.55	$ 0.38	$ 0.32	$ (0.06)	$ 0.17	$ (0.06)	$ 0.12	$ 0.28	$ 0.54	$ 2.05	$ 0.81	$ 0.88
Average common shares outstanding (in shares)	6,149	6,307	6,685	7,149	7,739	7,839	7,841	7,848	7,839	7,938	7,976	7,914	6,570	7,817	7,917
Diluted average common shares outstanding (in shares)	6,275	6,448	6,819	7,272	7,872	7,963	7,841	8,044	8,037	8,123	8,179	8,129	6,714	7,987	8,141