Derivative Financial Instruments - Impact on Interest Expense of Interest Rate Agreements Accounted for as Cash Flow Hedges (Details) - USD ($) $ in Thousands	9 Months Ended			12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Total interest expense				$ (448,005)	$ (479,808)	$ (239,039)
Cash Flow Hedging | Interest Rate Contract
Derivative [Line Items]
Net interest expense on cash flows hedges	$ (860)	$ (2,847)	$ (3,228)
Realized net losses reclassified from other comprehensive income	(3,188)	0	0
Total interest expense	$ (4,048)	$ (2,847)	$ (3,228)