LEASES - Maturities of Operating and Financing Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019	$ 58,586
2020	59,666
2021	60,856
2022	62,075
2023	63,211
After 2023	305,640
Total lease payments	610,034
Less: Interest	(225,735)
Present value of lease liabilities	384,299
2019		$ 58,291
2020		59,391
2021		60,575
2022		61,808
2023		63,065
After 2023		321,797
Total lease payments		624,927
Finance Leases
2019	429
2020	212
2021	197
2022	100
2023	0
After 2023	0
Total lease payments	938
Less: Interest	(89)
Present value of lease liabilities	849
2018		454
2019		174
2020		173
2021		127
2022		0
After 2022		0
Total lease payments		928
Operating and Finance Lease Liabilities, Payments, Due [Abstract]
2019	59,015	58,745
2020	59,878	59,565
2021	61,053	60,748
2022	62,175	61,935
2023	63,211	63,065
After 2023	305,640	321,797
Total lease payments	610,972	$ 625,855
Less: Interest	(225,824)
Present value of lease liabilities	$ 385,148