Derivative Instruments and Hedging Activity (Details) - Interest Rate Swap [Member] $ in Thousands	Jun. 30, 2018 USD ($) Number	Dec. 31, 2017 USD ($) Number
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Interest Rate Derivatives, Number of Instruments | Number	4	5
Interest Rate Derivatives, Notional Amount | $	$ 158,924	$ 184,304