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Term loan facility number of additional draws maximum.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Gross amount of debt extinguished.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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The cash inflow associated with the amount received from entity's raising of capital via private rather than public placement.

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Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Amount of cash inflow (outflow) from long-term debt wholly or partially secured by collateral. Excludes tax exempt secured debt.

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The amount of property, by major property class, net of accumulated depreciation, subject to or available for lease as of the balance sheet date.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Long-term Debt (Details Textual) $ in Thousands						1 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended
Long-term Debt (Details Textual) $ in Thousands	Jan. 29, 2015 USD ($)	Oct. 16, 2014 USD ($)	Jan. 15, 2014 USD ($)	Mar. 01, 2013 USD ($)	Sep. 04, 2012 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2013 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Feb. 19, 2016 USD ($)	Dec. 10, 2015 USD ($)	Feb. 28, 2007 USD ($)
Debt Instrument [Line Items]
Net book value of property									$ 848,717	$ 663,315
Proceeds from Issuance of Long-term Debt									725,306	418,682	$ 99,841
Loss on debt extinguishment									2,126	1,896	$ 392
Lease Fleet Financing [Member]
Debt Instrument [Line Items]
Net book value of property									563,700	$ 277,000
Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Outstanding principal balance on term loan				$ 175,000
Initial value of debt														$ 275,000
Notes redeemed					$ 100,000
Debt Instrument, Interest Rate, Stated Percentage														7.50%
Loss on debt extinguishment				$ 400
Longtrain Leasing I [Member] \| Refinanced Term Loan [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Percentage of interest on term loan										2.00%
Percentage of interest on term loan rate										2.20%
Interest reserve amount for term loan										$ 3,900
Initial value of debt			$ 316,200
Proceeds from Issuance of Long-term Debt			122,000
Carrying value of debt										309,000
Longtrain Leasing I [Member] \| Original Term Loan [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Net of fees and expenses						$ 98,400	$ 99,400
Number of additional draws on term loan						2
Number of additional draws incurred							2
Line of credit, additional borrowings							$ 99,800
Percentage of interest on term loan rate											2.70%
Notes redeemed			$ 194,200
Loss on debt extinguishment										$ 1,900
Longtrain Leasing I [Member] \| Original Term Loan [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Percentage of interest on term loan							2.50%
Longtrain Leasing III [Member] \| 2015 Notes [Domain] \| Private Placement [Member]
Debt Instrument [Line Items]
Interest reserve amount for term loan									16,900
Initial value of debt	$ 625,500
Notes redeemed	408,500
Proceeds from Issuance of Private Placement	$ 211,600
Loss on debt extinguishment								$ 2,100
Secured Debt [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Net of fees and expenses									$ 99,500
Percentage of interest on term loan									1.45%
Percentage of interest on term loan rate									1.90%
Line of Credit Facility, Maximum Borrowing Capacity													$ 200,000
Secured Debt [Member] \| Longtrain Leasing II [Member] \| Loan Facility October 2014 [Member]
Debt Instrument [Line Items]
Percentage of interest on term loan		1.45%
Percentage of interest on term loan rate										1.70%
Short-term Debt										$ 100,000
Initial value of debt		$ 100,000
Subsequent Event [Member] \| Secured Debt [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity												$ 200,000
Class A-1 Notes [Member] \| Longtrain Leasing III [Member] \| 2015 Notes [Domain] \| Private Placement [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.98%
Carrying value of debt									$ 226,300
Class A-2 Notes [Member] \| Longtrain Leasing III [Member] \| 2015 Notes [Domain] \| Private Placement [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.06%
Carrying value of debt									$ 375,500