LEASES (Schedule of Lease Assets and Liabilities, Weighted-Average Lease Term and Discount Rate) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
LEASES [Abstract]
Operating lease ROU assets	$ 488,607	$ 482,513	$ 461,712
Accumulated amortization	(66,982)	(59,385)	(40,782)
Finance lease assets	10,638	7,796	3,910
Accumulated amortization	(2,271)	(1,640)	(369)
Total lease assets	429,992	429,284	424,471
Current operating lease liabilities	38,131	36,969	32,045
Current finance lease liabilities	2,718	2,047	1,197
Noncurrent operating liabilities	397,306	399,582	399,489
Noncurrent finance lease liabilities	5,688	4,139	2,349
Total lease liabilities	$ 443,843	$ 442,737	$ 435,080
Weighted-average remaining lease term, Operating leases	9 years 2 months 12 days	9 years 6 months	10 years 1 month 6 days
Weighted-average remaining lease term, Finance leases	4 years	4 years 2 months 12 days	3 years 1 month 6 days
Weighted-average discount rate, Operating leases	3.30%	3.60%	4.20%
Weighted-average discount rate, Finance leases	1.30%	1.40%	2.70%