SHAREHOLDER'S EQUITY (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended					6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
ESPP [Line items]
Other current liabilities	$ 763					$ 763		$ 1,279
Other long term liabilities	944					944		1,041
Total Dividend Equivalent Liability	$ 1,707					$ 1,707		$ 2,320
Espp Shares Market Value	85.00%					85.00%
Employee stock purchase plan, authorized shares	1,000					1,000
ESPP Share Discount	15.00%					15.00%
Number of shares purchased			0	0	0
Non cash compensation expense recognized	$ 2,634	$ 2,951				$ 5,473	$ 6,055
Stock Repurchase Prgram Authorized Amount	$ 100,000					$ 100,000
Number of Shares Authorized to be Repurchased	0					0
ESPP [Member]
ESPP [Line items]
Number of shares purchased						159	100
Non cash compensation expense recognized						$ 131	$ 125