Financial Derivative Instruments (Details) - Cash Flow Hedging - Designated as Hedging Instrument - USD ($)	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Interest Rate Swap June 28 2016
Derivative [Line Items]
Notional Amount	$ 30,000,000
Fixed Rate Paid	0.94%
Fair Value	$ 1,447,000	$ 1,154,000	$ 1,108,000
Interest Rate Swap June 27 2016
Derivative [Line Items]
Notional Amount	$ 20,000,000
Fixed Rate Paid	0.893%
Fair Value	$ 994,000	801,000	778,000
Interest Rate Swap
Derivative [Line Items]
Notional Amount	50,000,000
Fair Value	$ 2,441,000	$ 1,955,000	$ 1,886,000