Fair Value (Assets and Liabilities Not Measured at Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Assets:
Cash and Restricted cash	$ 1,090,501	$ 620,135	$ 842,629	$ 724,215
Liabilities:
Variable-rate debt	1,866,406	2,229,958
Allowance for accounts receivable	20,800	15,600
Allowance for notes receivable	200	200
Level 1 | Carrying Amount
Assets:
Cash and Restricted cash	1,090,501	620,135
Level 1 | Estimated Fair Value
Assets:
Cash and Restricted cash	1,090,501	620,135
Level 3 | Carrying Amount
Assets:
Accounts receivable, net	10,087	12,279
Notes receivable, net	52,136	36,379
Level 3 | Estimated Fair Value
Assets:
Accounts receivable, net	10,087	12,279
Notes receivable, net	52,136	36,379
Level 2 | Carrying Amount
Liabilities:
Fixed-rate debt	2,387,189	1,908,660
Variable-rate debt	1,866,406	2,229,958
Level 2 | Estimated Fair Value
Liabilities:
Fixed-rate debt	2,395,405	1,949,773
Variable-rate debt	$ 1,866,406	$ 2,229,958