SEGMENT REPORTING - Total Revenues Based on Location of the Customer and Long-Lived Assets by Geographic Regions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total revenues
Revenues	$ 3,793,326	$ 3,856,132	$ 3,908,840	$ 3,751,210	$ 4,137,908	$ 4,291,900	$ 4,276,037	$ 3,925,327	$ 15,309,508	$ 16,631,172	$ 14,869,380
Long-lived assets
Total long-lived assets	695,696				405,423				695,696	405,423	442,212
Right-of-use lease assets	310,860								310,860
United States
Total revenues
Revenues									13,143,522	14,370,454	12,865,087
Long-lived assets
Total long-lived assets	489,129				321,766				489,129	321,766	335,072
Right-of-use lease assets	216,400								216,400
Other locations
Total revenues
Revenues									2,165,986	2,260,718	2,004,293
Long-lived assets
Total long-lived assets	206,567				$ 83,657				206,567	$ 83,657	$ 107,140
Right-of-use lease assets	$ 94,400								$ 94,400