DEBT - Schedule of Long-Term Debt (Parenthetical) (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Line of credit | $1.2 billion senior credit facility, due in 2022
Debt Instrument [Line Items]
Maximum borrowing capacity of line of credit facility	$ 1,200,000,000
Term loan | $950 million term loan, due in 2022
Debt Instrument [Line Items]
Maximum borrowing capacity of line of credit facility	950,000,000
Private placement notes | $125 million private placement notes, due in 2019
Debt Instrument [Line Items]
Long-term debt, face amount	125,000,000
Private placement notes | $225 million private placement notes, due in 2020
Debt Instrument [Line Items]
Long-term debt, face amount	225,000,000
Private placement notes | $150 million private placement notes, due in 2021
Debt Instrument [Line Items]
Long-term debt, face amount	150,000,000
Private placement notes | $125 million private placement notes, due in 2022
Debt Instrument [Line Items]
Long-term debt, face amount	125,000,000
Private placement notes | $200 million private placement notes, due in 2022
Debt Instrument [Line Items]
Long-term debt, face amount	200,000,000
Private placement notes | $100 million private placement notes, due in 2023
Debt Instrument [Line Items]
Long-term debt, face amount	100,000,000
Private placement notes | $150 million private placement notes, due in 2023
Debt Instrument [Line Items]
Long-term debt, face amount	$ 150,000,000
Promissory notes and deferred consideration | Notes weighted average maturity 2.6 and 2.7 years
Debt Instrument [Line Items]
Long-term debt, maturity	2 years 7 months 6 days	2 years 8 months 12 days
Foreign bank debt | Debt weighted average maturity 1.6 years and 1.9 years
Debt Instrument [Line Items]
Long-term debt, maturity	1 year 7 months 6 days	1 year 10 months 24 days