Long-term Debt (Details Textual) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
	Jan. 29, 2015	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 10, 2015
Long-term Debt (Textual) [Abstract]
Proceeds from Issuance of Long-term Debt		$ 0	$ 625,306
Loss on debt extinguishment		0	2,126
Long-term Debt		595,395
Property Subject to or Available for Operating Lease, Net		557,900		$ 563,700
Private Placement [Member]
Long-term Debt (Textual) [Abstract]
Initial value of debt	$ 625,500
Debt extinguished	408,500
Loss on debt extinguishment			$ 2,100
Restricted Cash and Cash Equivalents		16,800		$ 16,900
Proceeds from Issuance of Private Placement	$ 211,600
Private Placement [Member] | Class A-1 Notes [Member]
Long-term Debt (Textual) [Abstract]
Fixed interest rate of the notes	2.98%
Long-term Debt		219,900
Private Placement [Member] | Class A-2 Notes [Member]
Long-term Debt (Textual) [Abstract]
Fixed interest rate of the notes	4.06%
Long-term Debt		$ 375,500
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 200,000
Long-term Debt (Textual) [Abstract]
Base interest rate on credit facility		1.45%
Interest Rate at balance sheet date				1.90%
Proceeds from (Repayments of) Secured Debt				$ 99,500
Line of Credit Facility, Remaining Borrowing Capacity		$ 200,000
Longtrain Leasing III [Member] | 2015 Notes [Domain] | Private Placement [Member]
Long-term Debt (Textual) [Abstract]
Fair value of term loan		$ 601,900		$ 608,400