Derivative Instruments and Hedging Activities, Effects of Derivative Instruments on Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Interest Rate Swap through 9-15-2020 [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities [Abstract]
Notional/contract amount	$ 4,000	$ 4,000
Expiration date	Sep. 15, 2020	Sep. 15, 2020
Interest Rate Swap through 9-15-2020 [Member] | Cash Flow Hedging [Member] | Other Liabilities [Member]
Derivative Instruments and Hedging Activities [Abstract]
Fair Value	$ (39)	$ (119)
Interest Rate Swap through 6-15-2031 [Member] | Cash Flow Hedging [Member]
Derivative Instruments and Hedging Activities [Abstract]
Notional/contract amount	$ 4,000	$ 4,000
Expiration date	Jun. 15, 2031	Jun. 15, 2031
Interest Rate Swap through 6-15-2031 [Member] | Cash Flow Hedging [Member] | Other Assets [Member]
Derivative Instruments and Hedging Activities [Abstract]
Fair Value	$ 324	$ 164
Interest Rate Swap through 4-9-2025 [Member] | Fair Value Hedging [Member]
Derivative Instruments and Hedging Activities [Abstract]
Notional/contract amount	$ 1,149	$ 1,219
Expiration date	Apr. 09, 2025	Apr. 09, 2025
Interest Rate Swap through 4-9-2025 [Member] | Fair Value Hedging [Member] | Other Assets [Member]
Derivative Instruments and Hedging Activities [Abstract]
Fair Value	$ 57	$ 20
Interest Rate Swap through 2-12-2022 [Member] | Fair Value Hedging [Member]
Derivative Instruments and Hedging Activities [Abstract]
Notional/contract amount	$ 4,276	$ 4,475
Expiration date	Feb. 12, 2022	Feb. 12, 2022
Interest Rate Swap through 2-12-2022 [Member] | Fair Value Hedging [Member] | Other Assets [Member]
Derivative Instruments and Hedging Activities [Abstract]
Fair Value	$ 131	$ 49