NEW ACCOUNTING PRONOUNCEMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Convertible senior notes, net	$ 589,769				$ 518,203
Impact of ASU adoption	459,632	$ 522,468	$ 478,925		542,172	$ 529,322	$ 556,282	$ 566,611	$ 539,010
Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Convertible senior notes, net				$ 587,700
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact of ASU adoption	$ 316,150	$ 375,069	$ 340,223		339,879	$ 338,300	$ 359,989	$ 383,142	$ 410,919
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact of ASU adoption					(52,205)
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Convertible senior notes, net				$ 69,500
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact of ASU adoption					9,399
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings | Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impact of ASU adoption					$ 9,400