Derivative Financial Instruments (Details 2) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Offsetting Derivative Liabilities [Abstract]
Derivative Assets and Liabilities	$ 16,284	$ 55,549
Derivative Asset and Liability, Fair Value, Net	0	0
Derivative Asset and Liability, Amount Offset Against Collateral, Net	16,284	55,549
Current assets [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	16,767	56,255
Gross amounts netted in the consolidated balance sheets	(483)	(706)
Net amounts of assets presented in the consolidated balance sheets	16,284	55,549
Other assets [Member]
Offsetting Derivative Assets [Abstract]
Gross amounts of recognized assets	0	0
Gross amounts netted in the consolidated balance sheets	0	0
Net amounts of assets presented in the consolidated balance sheets	0	0
Current liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	(483)	(706)
Gross amounts netted in the consolidated balance sheet	(483)	(706)
Net amounts of liabilities presented in the consolidated balance sheet	0	0
Other liabilities [Member]
Offsetting Derivative Liabilities [Abstract]
Gross amounts of recognized liabilities	0	0
Gross amounts netted in the consolidated balance sheet	0	0
Net amounts of liabilities presented in the consolidated balance sheet	$ 0	$ 0