Fair Value Measurements and Derivative Instruments Reporting (Fair value and basis of valuation of financial liabilities) (Details) - Interest Rate Swap Asset [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities	(315)	(275)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial Liabilities