Debt (Schedule of Interest Rate Derivatives) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Interest Rate Swap, Date Entered, May 2012 [Member]
Derivative [Line Items]
Derivative, Inception Date	May 31, 2012
Derivative, Maturity Date	Apr. 30, 2019
Derivative, Fixed Interest Rate	2.84%
Debt Instrument, Description of Variable Rate Basis	1-month LIBOR
Derivative, Notional Amount	$ 40,000
Interest Rate Swap, Date Entered, June 2013 [Member]
Derivative [Line Items]
Derivative, Inception Date	Jun. 30, 2013
Derivative, Maturity Date	Jun. 30, 2020
Derivative, Fixed Interest Rate	3.41%
Debt Instrument, Description of Variable Rate Basis	1-month LIBOR
Derivative, Notional Amount	$ 80,000
Interest Rate Swap, Date Entered, March 2014 [Member]
Derivative [Line Items]
Derivative, Inception Date	Mar. 31, 2014
Derivative, Maturity Date	Jun. 30, 2020
Derivative, Fixed Interest Rate	3.46%
Debt Instrument, Description of Variable Rate Basis	1-month LIBOR
Derivative, Notional Amount	$ 130,000
Fair Value, Inputs, Level 2 [Member]
Derivative [Line Items]
Cash Flow Hedge Derivative Instrument Assets at Fair Value	2,137	$ 159
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap, Date Entered, May 2012 [Member]
Derivative [Line Items]
Cash Flow Hedge Derivative Instrument Assets at Fair Value	265
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap, Date Entered, June 2013 [Member]
Derivative [Line Items]
Cash Flow Hedge Derivative Instrument Assets at Fair Value	761
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap, Date Entered, March 2014 [Member]
Derivative [Line Items]
Cash Flow Hedge Derivative Instrument Assets at Fair Value	$ 1,111