Goodwill and Other Intangibles Investment in West Atlantic (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Goodwill	$ 37,279	$ 37,133
Investment in West Atlantic [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	7,900	$ 9,900
Goodwill	5,500
Investments in A321 [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments	5,300
Payments to Acquire Interest in Joint Venture	$ 6,300