Derivatives and Hedging Activities (Derivative Instruments, Gain (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Amount of loss reclassified from accumulated other comprehensive loss into income as interest expense	$ (1,500)
Total interest expense recorded in the consolidated statement of operations	77,994	$ 66,789	$ 60,305
Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Amount of (loss) gain recognized in accumulated other comprehensive (loss) income on interest rate derivatives (effective portion) [1]	(979)
Amount of (loss) gain recognized in accumulated other comprehensive (loss) income on interest rate derivatives (effective portion) [1]		(670)	56
Amount of gain recognized in income on derivative (ineffective portion, reclassifications of missed forecasted transactions and amounts excluded from effectiveness testing)	0	81	0
Interest Expense | Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Amount of loss reclassified from accumulated other comprehensive loss into income as interest expense	$ (36)
Amount of loss reclassified from accumulated other comprehensive loss into income as interest expense		$ (125)	$ (39)