Derivatives (Net Derivatives As Reflected On The Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ 725	$ 4,807
Accrued expenses and other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	(693)	(101)
Heating Oil and Foreign Currency [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Net derivatives as classified in the balance sheet	$ 1,418	$ 4,908