LONG-TERM DEBT - Convertible Notes (Details)					3 Months Ended	12 Months Ended
	Apr. 15, 2020 USD ($) $ / shares	Mar. 15, 2020 USD ($) $ / shares	Feb. 04, 2020 USD ($)	Jan. 29, 2020 $ / shares	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2021 USD ($) $ / shares	Dec. 31, 2020 USD ($)	Nov. 05, 2021	Aug. 31, 2021 USD ($)	Mar. 31, 2021	Mar. 10, 2021
Long-term debt
Outstanding Principal					$ 283,034,000	$ 283,034,000	$ 280,500,000
Debt conversion amount							57,359,000
Interest rate (as a percent)								0.73%	0.77%	0.73%	0.22%
Unamortized debt discount of notes					3,565,000	3,565,000
Gain (Loss) on Extinguishment of Debt						(3,431,000)	1,141,000
Outstanding amount					278,273,000	278,273,000	273,830,000		$ 15,000,000.0
4.50% Convertible Senior Notes due 2020
Long-term debt
Outstanding Principal		$ 75,000,000.0
Interest rate (as a percent)		4.50%
Debt instrument conversion ratio		14.5136
Conversion price per share (in dollars per share) | $ / shares		$ 68.90
Threshold principal amount for adjusted conversion price		$ 1,000
Proceeds from private placement			$ 5,900,000
Outstanding amount			75,000,000.0
3.875% Convertible Senior Notes due 2025
Long-term debt
Outstanding Principal			17,600,000		$ 51,034,000	$ 51,034,000
Debt conversion amount			57,400,000
Interest rate (as a percent)					3.875%	3.875%
Proceeds from private placement			11,700,000
Repurchase of notes			5,900,000
Outstanding amount			$ 11,700,000		$ 47,469,000	$ 47,469,000	56,296,000
2025 Notes maturing on April 15, 2025
Long-term debt
Debt instrument conversion ratio	12.7910				19.4453
Conversion price per share (in dollars per share) | $ / shares	$ 78.18				$ 51.43	$ 51.43
Threshold principal amount for adjusted conversion price	$ 1,000				$ 1,000
Dividends Declared and Paid - Common Stock (in dollars per share) | $ / shares	$ 0.13
Premium initial conversion price				20.00%
Closing share price (in dollars per share) | $ / shares				$ 65.15
Sinking fund provided					0	$ 0
Unamortized debt discount of notes					1,600,000	1,600,000	2,600,000
Gain (Loss) on Extinguishment of Debt						2,900,000	1,100,000
Repurchase of notes					11,400,000	11,400,000	$ 12,500,000
Convertible Debt | 2025 Notes maturing on April 15, 2025
Long-term debt
Threshold principal amount for adjusted conversion price						1,000
Unamortized debt discount of notes					3,600,000	3,600,000
Outstanding amount					$ 51,000,000.0	$ 51,000,000.0