FAIR VALUE (Assets and Liabilities Not Measured at Fair Value) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Assets:
Cash and restricted cash	$ 848,600	$ 724,215	$ 736,369	$ 964,300
Liabilities:
Variable-rate debt (c)	1,561,549	1,551,336
Allowance for doubtful accounts	10,000	10,700
Allowance for notes receivable	100	100
Quoted Prices in Active Markets for Identical Assets (Level 1) | Carrying Amount
Assets:
Cash and restricted cash	848,600	724,215
Quoted Prices in Active Markets for Identical Assets (Level 1) | Estimated Fair Value
Assets:
Cash and restricted cash	848,600	724,215
Significant Unobservable Inputs (Level 3) | Carrying Amount
Assets:
Accounts receivable, net (a)	19,980	12,589
Notes receivable, net (b)	300	4,694
Significant Unobservable Inputs (Level 3) | Estimated Fair Value
Assets:
Accounts receivable, net (a)	19,980	12,589
Notes receivable, net (b)	300	4,694
Significant Other Observable Inputs (Level 2) | Carrying Amount
Liabilities:
Fixed-rate debt (c)	1,904,165	1,663,875
Variable-rate debt (c)	1,561,549	1,551,336
Significant Other Observable Inputs (Level 2) | Estimated Fair Value
Liabilities:
Fixed-rate debt (c)	1,933,715	1,608,635
Variable-rate debt (c)	$ 1,561,549	$ 1,551,336