SHARE CAPITAL - Narrative (Details) - USD ($)		6 Months Ended
	Apr. 26, 2017	Jun. 30, 2020	Jun. 30, 2019	Jul. 31, 2020	Mar. 26, 2020	Dec. 31, 2019	Aug. 07, 2018	Apr. 25, 2017
Senior Unsecured Convertible Notes | Senior Notes
Class of Stock [Line Items]
Convertible debt, amount							$ 100,000,000.0
Debt instrument, amount authorized for repurchase					$ 25,000,000.0
Debt interest rate							4.00%
Subsequent Event | Senior Unsecured Convertible Notes | Senior Notes
Class of Stock [Line Items]
Convertible debt, amount				$ 25,000,000.0
Common Class A
Class of Stock [Line Items]
Number of shares authorized for issuance period increase	1,500,000
Number of shares authorized for issuance	5,000,000.0							3,500,000
Number of shares available for grant		62,531				555,805
Repurchase of ordinary shares (in shares)		1,161,659	0
Ordinary share capital, par value (in dollars per share)		$ 0.10				$ 0.10
Common Class A | Subsequent Event
Class of Stock [Line Items]
Stock repurchase program, remaining number of shares to be repurchased				3,800,000
Common Class B
Class of Stock [Line Items]
Repurchase of ordinary shares (in shares)		0	0
Ordinary share capital, par value (in dollars per share)		$ 0.10				$ 0.10