TREASURY STOCK - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions		1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Feb. 05, 2020	Jun. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Dec. 11, 2018
Equity, Class of Treasury Stock [Line Items]
Treasury stock (in shares)		4.9	4.9		4.9		2.9
Treasury stock		$ 235,200,000	$ 235,200,000		$ 235,200,000		$ 119,900,000
Treasury stock, average cost per share (in dollars per share)					$ 47.86		$ 41.87
Stock repurchase program, authorized amount (up to)								$ 225,000,000.0
Stock repurchased during period (in shares)	1.3	0.6			1.9
Net proceeds from offering of convertible senior notes					$ 575,000,000	$ 0
Accelerated share repurchase program, payment	$ 92,400,000
Accelerated shares repurchased, amount	$ 100,000,000.0		0	$ 92,368,000
Accelerated share repurchases, percentage of expected total repurchased	80.00%
Remaining amount under share repurchase		$ 125,000,000.0	$ 125,000,000.0		125,000,000.0
Convertible Debt
Equity, Class of Treasury Stock [Line Items]
Net proceeds from offering of convertible senior notes					100,000,000.0
Convertible Debt | Certain Purchasers
Equity, Class of Treasury Stock [Line Items]
Net proceeds from offering of convertible senior notes					$ 7,600,000