Schedule I - Condensed Financial Information (Details 5) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended												12 Months Ended
	Nov. 30, 2010	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income		$ 2,211	$ (7,194)	$ 3,229	$ 3,289	$ 3,648	$ 2,316	$ 3,481	$ 5,063	$ 4,010	$ 3,083	$ 1,907	$ 3,050	$ 1,535	$ 14,508	$ 12,050
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense														52,591	51,250	48,704
Write-down of equipment														5,874	3,341	2,874
Stock-based compensation expenses														3,144	3,173	2,678
Amortization of deferred costs														3,982	4,544	5,246
Amortization of interest rate derivative cost														(236)	483	2,956
Allowances and provisions														503	54	(44)
Gain on sale of leased equipment														(5,499)	(11,110)	(7,990)
Gain on insurance settlement														(173)
Gain on sale of interest in joint venture	(2,000)															(2,020)
Other non-cash items															(1,113)
Income from joint ventures, net of distributions														(957)	(485)	(160)
Non-cash portion of loss on debt extinguishment														15,462	343
Deferred income taxes														1,161	9,377	7,630
Changes in assets and liabilities:
Receivables														(4,985)	385	(3,045)
Notes receivable														542	205	196
Other assets														(1,256)	(4,507)	(3,108)
Accounts payable and accrued expenses														(5,936)	(2,021)	3,733
Maintenance reserves														8,804	4,067	3,690
Security deposits														678	552	245
Unearned lease revenue														301	569	(213)
Net cash provided by operating activities														67,311	76,662	56,633
Cash flows from investing activities:
Proceeds from sale of equipment held for operating lease (net of selling expenses)														34,607	110,777	63,777
Proceeds from sale of interest in joint ventures	3,500															3,500
Investment in joint venture														(5,636)	(8,943)
Purchase of equipment held for operating lease														(61,464)	(144,334)	(121,509)
Purchase of property, equipment and furnishings														(1,219)	(904)	(399)
Net cash used in investing activities														(31,958)	(45,158)	(54,631)
Cash flows from financing activities:
Proceeds from issuance of notes payable														603,693	132,409	174,841
Debt issuance cost														(11,949)	(3,691)	(268)
Preferred stock dividends														(2,493)	(3,128)	(3,128)
Proceeds from shares issued under stock compensation plans														1,725	672	1,269
Cancellation of restricted stock units in satisfaction of withholding tax														(1,194)	(968)	(776)
Excess tax benefit from stock-based compensation															779	422
Redemption of preferred stock														(34,750)
Repurchase of common stock														(12,736)	(5,661)	(4,156)
Cash settlement of stock options															(1,262)
Principal payments on notes payable														(626,923)	(146,439)	(170,037)
Net cash used in financing activities														(36,414)	(27,289)	(1,833)
Increase/(Decrease) in cash and cash equivalents														(1,061)	4,215	169
Cash and cash equivalents at beginning of period					6,440				2,225				2,056	6,440	2,225	2,056
Cash and cash equivalents at end of period		5,379				6,440				2,225				5,379	6,440	2,225
Net cash paid for:
Interest														21,528	20,063	17,629
Income Taxes														105	155	549
Supplemental disclosures of non-cash investing activities:
Engines and equipment, transferred from Held for Operating Lease to Held for Sale but not settled														22,935	17,067	70,000
Parent company
Cash flows from operating activities:
Net income														1,535	14,508	12,050
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in income of subsidiaries														(6,314)	(18,516)	(15,623)
Depreciation expense														18,764	17,783	14,800
Write-down of equipment														2,621	2,306	2,874
Stock-based compensation expenses														3,144	3,173	2,678
Amortization of deferred costs														2,215	1,360	2,719
Amortization of interest rate derivative cost														(236)	483	2,956
Allowances and provisions														34	(157)	(21)
Gain on sale of leased equipment														(3,605)	(7,895)	(3,782)
Gain on insurance settlement														(173)
Gain on sale of interest in joint venture																(2,020)
Other non-cash items															(1,113)
Income from joint ventures, net of distributions														(957)	(485)	(160)
Non-cash portion of loss on debt extinguishment														94	343
Deferred income taxes														(2,196)	4,325	(2,041)
Changes in assets and liabilities:
Receivables														(292)	(1,037)	(908)
Notes receivable														5	78	259
Other assets														(1,329)	(910)	(2,146)
Accounts payable and accrued expenses														(2,421)	(9,066)	4,473
Due to / from subsidiaries														4,946	553	(546)
Maintenance reserves														2,898	3,008	(2,590)
Security deposits														(641)	759	379
Unearned lease revenue														335	(72)	144
Net cash provided by operating activities														18,427	9,428	13,495
Cash flows from investing activities:
Increase in investment in subsidiaries														(100,649)	(1,800)	(21,814)
Distributions received from subsidiaries														106,183	22,851	39,314
Proceeds from sale of equipment held for operating lease (net of selling expenses)														21,371	61,309	13,520
Proceeds from sale of interest in joint ventures																3,500
Investment in joint venture														(5,636)	(8,943)
Purchase of equipment held for operating lease														(40,465)	(99,132)	(25,946)
Purchase of property, equipment and furnishings														(1,219)	(904)	(399)
Net cash used in investing activities														(20,415)	(26,619)	8,175
Cash flows from financing activities:
Proceeds from issuance of notes payable														236,392	132,409	120,466
Debt issuance cost														(516)	(3,565)	(268)
Preferred stock dividends														(2,493)	(3,128)	(3,128)
Proceeds from shares issued under stock compensation plans														1,725	672	1,268
Cancellation of restricted stock units in satisfaction of withholding tax														(1,194)	(968)	(775)
Excess tax benefit from stock-based compensation															779	422
Redemption of preferred stock														(34,750)
Repurchase of common stock														(12,736)	(5,661)	(4,156)
Cash settlement of stock options															(1,262)
Principal payments on notes payable														(186,727)	(97,858)	(135,309)
Net cash used in financing activities														(299)	21,418	(21,480)
Increase/(Decrease) in cash and cash equivalents														(2,287)	4,227	190
Cash and cash equivalents at beginning of period					6,429				2,202				2,012	6,429	2,202	2,012
Cash and cash equivalents at end of period		4,142				6,429				2,202				4,142	6,429	2,202
Net cash paid for:
Interest														8,105	9,307	7,462
Income Taxes														101	155	541
Supplemental disclosures of non-cash investing activities:
Engines and equipment, transferred from Held for Operating Lease to Held for Sale but not settled														14,156	17,067	70
Engines and equipment, transferred from parent to its subsidiaries														$ 56,562	$ 2,448	$ 14,417