SCHEDULE I - Parent Company Information - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 43,231	$ 62,158	$ 14,069
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	76,814	66,023	66,280
Write-down of equipment	10,651	24,930	9,514
Stock-based compensation expenses	5,410	4,270	3,717
Excess tax benefit from stock-based compensation			236
Amortization of deferred costs	6,403	5,183	4,271
Allowances and provisions	1,503	162	(571)
Gain on sale of leased equipment	(6,944)	(4,929)	(3,482)
Gain on insurance settlement		(1,288)
Income from joint ventures	(3,800)	(7,158)	(1,813)
Loss on extinguishment of debt			137
Loss on disposal of property, equipment and furnishings	(41)
Deferred income taxes	12,057	(26,393)	9,099
Changes in assets and liabilities:
Receivables	(5,925)	(2,525)	(2,287)
Distributions received from joint ventures	5,730	1,880	1,167
Spare parts inventory	12,111	(1,855)	(5,093)
Intangibles			(1,511)
Other assets	(3,453)	(970)	(1,707)
Accounts payable and accrued expenses	12,543	1,129	2,330
Maintenance reserves	21,964	7,994	548
Security deposits	3,075	6,246	(4,048)
Unearned lease revenue	(2,642)	2,279	732
Net cash provided by operating activities	188,687	137,136	91,588
Cash flows from investing activities:
Proceeds from sale of equipment held for operating lease (net of selling expenses)	64,429	43,791	62,525
Capital contribution to joint ventures			(5,545)
Proceeds from Insurance Settlement, Investing Activities		14,886
Purchase of equipment held for operating lease	(441,416)	(373,483)	(173,662)
Purchase of maintenance rights			(5,530)
Purchase of property, equipment and furnishings	(3,487)	(10,788)	(1,006)
Net cash used in investing activities	(380,474)	(325,594)	(123,218)
Cash flows from financing activities:
Proceeds from issuance of debt obligations	759,439	686,200	149,000
Debt issuance cost	(7,748)	(8,262)	(3,808)
Principal payments on debt obligations	(504,753)	(496,160)	(113,981)
Interest bearing security deposits		(2,261)	455
Proceeds from shares issued under stock compensation plans	245	177	155
Repurchase of common stock	(16,135)	(3,546)	(28,958)
Proceeds from the issuance of preferred stock		29,665	19,752
Preferred stock dividends	(3,348)	(1,311)
Cancellation of restricted stock units in satisfaction of withholding tax	(1,288)	(1,094)	(1,369)
Net cash provided by financing activities	226,412	203,408	21,246
Increase/(decrease) in cash, cash equivalents and restricted cash	34,625	14,950	(10,384)
Cash, cash equivalents and restricted cash at beginning of period	47,324	32,374	42,758
Cash, cash equivalents and restricted cash at end of period	81,949	47,324	32,374
Net cash paid for:
Interest	59,122	42,817	37,319
Income Taxes	1,073	440	459
Supplemental disclosures of non-cash activities:
Transfers from Equipment held for operating lease to Equipment held for sale		45,018	28,560
Transfers from Equipment held for sale to Spare parts inventory	26,387	210
Transfers from Property, equipment and furnishings to Equipment held for lease			2,925
Accrued Preferred Stock Dividends	686	783	281
Accretion of preferred stock issuance costs	83	46	8
Parent Company [Member]
Cash flows from operating activities:
Net income	43,231	62,158	14,069
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income of subsidiaries	(43,937)	(54,043)	(10,782)
Depreciation expense	34,795	40,560	43,451
Write-down of equipment	2,567	17,881	5,989
Stock-based compensation expenses	5,410	4,270	3,717
Excess tax benefit from stock-based compensation			236
Amortization of deferred costs	3,324	3,085	2,704
Allowances and provisions	439	76	(1)
Gain on sale of leased equipment	(6,183)	(3,696)	(3,322)
Gain on insurance settlement		(1,288)
Income from joint ventures	(3,800)	(7,158)	(1,813)
Loss on extinguishment of debt			137
Loss on disposal of property, equipment and furnishings	41
Deferred income taxes	(434)	4,843	4,710
Changes in assets and liabilities:
Receivables	4,073	5,366	(4,884)
Distributions received from joint ventures	5,730	1,880	1,167
Spare parts inventory	7,320	5,612	(1,608)
Intangibles			(750)
Other assets	(3,983)	(4,259)	(2,648)
Accounts payable and accrued expenses	19,459	2,370	3,723
Due to / from subsidiaries	41,449	8,584	(4,437)
Maintenance reserves	(9,500)	7,906	16,583
Security deposits	(6,773)	6,876	(2,283)
Unearned lease revenue	(3,034)	906	878
Net cash provided by operating activities	90,194	101,929	64,836
Cash flows from investing activities:
Increase in investment in subsidiaries	(9,104)	(45,609)	(2,329)
Distributions received from subsidiaries	388,910	347,626	15,500
Proceeds from sale of equipment held for operating lease (net of selling expenses)	48,049	33,118	60,893
Capital contribution to joint ventures			(5,545)
Proceeds from Insurance Settlement, Investing Activities		14,886
Purchase of equipment held for operating lease	(417,857)	(354,918)	(167,874)
Purchase of maintenance rights			(5,530)
Purchase of property, equipment and furnishings	(1,104)	(268)	(443)
Net cash used in investing activities	8,894	(5,165)	(105,328)
Cash flows from financing activities:
Proceeds from issuance of debt obligations	386,000	350,500	149,000
Debt issuance cost			(3,808)
Principal payments on debt obligations	(462,119)	(470,606)	(93,055)
Interest bearing security deposits		(2,261)	455
Proceeds from shares issued under stock compensation plans	245	177	155
Repurchase of common stock	(16,136)	(3,546)	(28,958)
Proceeds from the issuance of preferred stock		29,663	19,752
Preferred stock dividends	(3,348)	(1,311)
Cancellation of restricted stock units in satisfaction of withholding tax	(1,288)	(1,094)	(1,369)
Net cash provided by financing activities	(96,646)	(98,478)	42,172
Increase/(decrease) in cash, cash equivalents and restricted cash	2,442	(1,714)	1,680
Cash, cash equivalents and restricted cash at beginning of period	2,860	4,574	2,894
Cash, cash equivalents and restricted cash at end of period	5,302	2,860	4,574
Net cash paid for:
Interest	23,525	21,761	20,619
Income Taxes	795	180	20
Supplemental disclosures of non-cash activities:
Engines and equipment transferred to the parent from its subsidiaries		17,910	229
Engines and equipment transferred to the subsidiaries from the parent	42,456
Transfers from Equipment held for operating lease to Equipment held for sale		31,571	18,194
Transfers from Equipment held for sale to Spare parts inventory	26,387
Transfers from Property, equipment and furnishings to Equipment held for lease			2,925
Accrued Preferred Stock Dividends	686	783	281
Accretion of preferred stock issuance costs	$ 83	$ 46	$ 8