Financial Instruments and Fair Values - Effect of Derivative Financial Instruments Designated as Cash Flow Hedges (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	$ (17,695)	$ (7,390)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	(796)	(149)
Interest expense	(19,618)	(20,689)
Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain (loss) recognized in other comprehensive income (loss)	(17,695)	(7,390)
Amount of gain (loss) reclassified from accumulated other comprehensive income (loss) into interest expense	(796)	(149)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated other comprehensive income (loss) | Interest Rate Swap
Derivative Instruments, Gain (Loss) [Line Items]
Interest expense	$ (796)	$ (149)