Fair Value Measurements (Financial Assets and Liabilities Measured on a Recurring Basis at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	$ 4,598	$ 4,095
Fair Value, Inputs, Level 1 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	4,055	3,799
Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	543	296
Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Liabilities, fair value, recurring		476
Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Liabilities, fair value, recurring		476
Marketable Securities [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	1,907	1,763
Marketable Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	1,907	1,763
Marketable Securities - Restricted [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	2,148	2,036
Marketable Securities - Restricted [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	2,148	2,036
Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	543	296
Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Assets, fair value, recurring	$ 543	$ 296