GOODWILL (Goodwill by Segment) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill, impairment loss	$ 0	$ 0	$ 0
Goodwill [Roll Forward]
Goodwill, beginning balance	1,283,457,000	1,254,866,000
Acquisitions	329,938,000	25,717,000
Effect of foreign currency translation	(1,860,000)	2,874,000
Goodwill, ending balance	1,611,535,000	1,283,457,000	1,254,866,000
North America [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	1,253,494,000	1,227,777,000
Acquisitions	319,594,000	25,717,000
Effect of foreign currency translation	0	0
Goodwill, ending balance	1,573,088,000	1,253,494,000	1,227,777,000
International [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	29,963,000	27,089,000
Acquisitions	10,344,000	0
Effect of foreign currency translation	(1,860,000)	2,874,000
Goodwill, ending balance	$ 38,447,000	$ 29,963,000	$ 27,089,000