Derivative Financial Instruments and Hedging Activities - Gain (Loss) in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Unrealized gains (losses) relating to interest rate swaps	$ 220	$ (177)	$ (1,530)	$ (1,169)
Interest rate swap agreements
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Unrealized gains (losses) relating to interest rate swaps	$ 220	$ (177)	$ (1,530)	$ (1,077)