Special Charges (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Feb. 29, 2016 USD ($) aircraft	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)
Property, Plant and Equipment [Line Items]
Payments for Purchase of Other Assets		$ 159,829	$ 184,609
Special charges		16,202	$ 425
Aircraft [Member]
Property, Plant and Equipment [Line Items]
Number of Operating Lease Agreements Terminated | aircraft	2
Payments to Acquire Equipment on Lease	$ 44,000
Payments for Purchase of Other Assets	23,500
Noncash or Part Noncash Acquisition, Description	$ 20,500
Fair Value of Assets Acquired		$ 27,400