Derivative Financial Instruments and Hedging Activities - Gain (Loss) in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Unrealized losses relating to interest rate swaps	$ (340)	$ (584)	$ (1,750)	$ (992)
Interest rate swap agreements
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Unrealized losses relating to interest rate swaps	$ (340)	$ (584)	$ (1,750)	$ (965)