Impairment Charges and Other Impairment Charges and Other (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015
Asset Impairment Charges [Abstract]
Impairment charges and other	$ 0		$ 1,313	$ 9,800	$ 0	$ 11,120
Assets Held-for-sale, Not Part of Disposal Group			$ 13,500			$ 13,500
Proceeds from sale of aircraft		$ 12,200