INCOME TAXES - Reconciliation of Tax Rate for TRS and Total Provision for TRS and Operating Partnership (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of the federal statutory rate to the effective income tax rate for the TRSs
Statutory federal income tax provision		$ 35,418	$ 37,384	$ 44,033
Nontaxable income of the REIT		(35,073)	(38,575)	(41,619)
Impact of graduated corporate tax rates		(10)	34	(69)
State income taxes, net of federal tax benefit		716	548	817
Provision to return and deferred adjustment		0	(872)	0
Effect of permanent differences and other		17	31	(161)
Effect of federal tax law change	$ 600	606	0	0
Decrease in valuation allowance		0	0	(2,448)
Income tax expense (benefit)		$ 1,674	$ (1,450)	$ 553