COMMON STOCK - Summary of Convertible Units (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Net carrying amount	$ 3,206,195	$ 2,919,201
Convertible | 2021 Series B Remarketable Junior Subordinated Notes due 2029
Debt Instrument [Line Items]
Principal	300,000
Unamortized debt discount and issuance costs	9,000
Net carrying amount	291,000
Carrying amount of the equity component	0
Convertible | 2018 Series A Remarketable Junior Notes due 2031
Debt Instrument [Line Items]
Principal	287,500	287,500
Unamortized debt discount and issuance costs	7,041	7,181
Net carrying amount	280,459	280,319
Carrying amount of the equity component	$ 0	$ 0