Derivative Instruments and Hedging Activities - Effects of Derivative Instruments on Statement of Comprehensive Income and Income Statement (Details) - Interest Rate Swap - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosures
Amount of (gain)/loss recognized in OCI on derivative	$ 1,553	$ 1,901
Cash Flow Hedging | Interest Expense
Derivative Instruments and Hedging Activities Disclosures
Amount of (gain)/loss reclassified from accumulated OCI into income	$ 772	$ (640)