Other Long Term Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Other Long Term Liabilities [Abstract]
Deferred Gains, net of Amortization	$ 14,944	$ 17,917
Billings in Excess of Cost	3,654
Pension and Post Retirement	10,778	12,497
Alabama Lease Incentive	4,591	5,739
Insurance Reserves	4,674	4,941
Derivatives	121	7,050
Deferred Tax Liability	309	408
Other	1,141	1,732
Other Long Term Liabilities	$ 40,212	$ 50,284