FAIR VALUE (Assets and Liabilities Not Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Assets:
Cash and Restricted cash	$ 1,242,999	$ 620,135	$ 724,215	$ 964,300
Liabilities:
Variable-rate debt	1,945,344	2,229,958
Accounts receivable, allowance	24,000	15,600
Notes Receivable
Liabilities:
Notes receivable, allowance	156	209
Level 1 | Reported Value Measurement
Assets:
Cash and Restricted cash	1,242,997	620,135
Level 1 | Estimate of Fair Value Measurement
Assets:
Cash and Restricted cash	1,242,997	620,135
Level 3 | Reported Value Measurement
Assets:
Accounts receivable, net	7,437	12,279
Notes receivable, net	622	36,379
Level 3 | Estimate of Fair Value Measurement
Assets:
Accounts receivable, net	7,437	12,279
Notes receivable, net	622	36,379
Level 2 | Reported Value Measurement
Liabilities:
Fixed-rate debt	2,374,822	1,908,660
Variable-rate debt	1,945,344	2,229,958
Level 2 | Estimate of Fair Value Measurement
Liabilities:
Fixed-rate debt	2,461,155	1,949,773
Variable-rate debt	$ 1,945,344	$ 2,229,958