Derivative Financial Instruments - Changes in Net Loss on Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) (Details) - Interest rate swap agreements - Cash flow hedges - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Changes in Net Gain or Loss on Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period	$ (19,612)	$ (10,560)	$ (10,137)	$ (2,936)
Unrealized loss recognized in other comprehensive loss, net of tax	(455)	(2,060)	(12,518)	(10,135)
Reclassification to interest expense, net	1,997	419	4,585	870
Balance at the end of the period	$ (18,070)	$ (12,201)	$ (18,070)	$ (12,201)