DEBT (Narrative) (Details) $ in Thousands	1 Months Ended		3 Months Ended	9 Months Ended
	Jun. 30, 2020 USD ($)	May 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Sep. 30, 2020 USD ($) item	Sep. 30, 2019 USD ($)	Apr. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Discounts and debt issuance costs				$ 6,028	$ 3,730
Total long-term debt - face value				3,357,906	2,846,378		$ 2,846,373
Net proceeds		$ 741,417
Repayment of long-term debt				250,018	17
Short-term debt				0	0		0
Proceeds from issuance of long-term debt				$ 750,000	0
Term Loan Due April 2021 [Member] | Term Loan Due [Member]
Debt Instrument [Line Items]
Available borrowing capacity	$ 500,000		$ 500,000
Repayments of debt			$ 250,000
Investment-Grade Type Covenants Governed [Member]
Debt Instrument [Line Items]
Number of indentures with customary investment-grade type covenants | item				3
Bank Line of Credit [Member]
Debt Instrument [Line Items]
Transaction fees				$ 4,632
Maximum borrowing capacity				$ 1,000,000
Commitment fee				0.175%
Line of credit number of primary negative covenants | item				2
Number of quarters debt to EBITDA maximum ratio limit on certain acquisitions | item				4
Debt issued, term				5 years
Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				1.375%
Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				0.375%
Bank Line of Credit [Member] | Delayed Draw Term Loan And Line Of Credit [Member]
Debt Instrument [Line Items]
Available borrowing capacity				$ 943,371
Short-term debt				$ 0
Bank Line of Credit [Member] | Maximum, Upon Certain Acquisitions [Member]
Debt Instrument [Line Items]
Debt to EBITDA ratio				3.75
Standby Letters of Credit [Member]
Debt Instrument [Line Items]
Outstanding standby letters of credit				$ 56,629
Period of standby letters of credit				1 year
Standby Letters of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				0.175%
Maximum [Member] | Term Loan Due April 2021 [Member] | Term Loan Due [Member]
Debt Instrument [Line Items]
Short-term debt						$ 750,000
Maximum [Member] | Bank Line of Credit [Member]
Debt Instrument [Line Items]
Debt to EBITDA ratio				3.50
Commitment fee				0.275%
Maximum [Member] | Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				1.875%
Maximum [Member] | Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				0.875%
Minimum [Member] | Bank Line of Credit [Member]
Debt Instrument [Line Items]
Commitment fee				0.125%
Minimum [Member] | Bank Line of Credit [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				1.125%
Minimum [Member] | Bank Line of Credit [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Applicable margin on borrowing rate				0.125%
Notes [Member]
Debt Instrument [Line Items]
Total long-term debt - face value				$ 3,357,906
Notes [Member] | Investment-Grade Type Covenants Governed [Member]
Debt Instrument [Line Items]
Total long-term debt - face value				3,346,188
Notes [Member] | 3.50% notes due 2030 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 750,000		$ 750,000	0		0
Maturity year		2030		2030
Interest rate		3.50%		3.50%
Notes [Member] | Floating-Rate Notes Due 2020 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value		$ 250,000		$ 0	250,000		250,000
Maturity year				2020
Repayment of long-term debt	$ 250,000
Notes [Member] | Floating-Rate Notes Due 2021 [Member]
Debt Instrument [Line Items]
Total long-term debt - face value				$ 500,000	$ 500,000		$ 500,000
Maturity year				2021
Face value				$ 500,000