Derivative Instruments and Hedging Activities - Cash Flow Hedge Agreements (Details) - Interest Rate Swap - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Derivative [Line Items]
Amount of hedged item	$ 20,000
Amount of gain recognized in AOCI	48	$ 0	$ 0
Amount of gain reclassified from AOCI interest expense	$ 0	$ 0	$ 0