SELECTED QUARTERLY INFORMATION (Details) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Jul. 31, 2020	Dec. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Mar. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares
Quarterly Financial Information Disclosure [Abstract]
Revenues		$ 150,693	$ 121,129	$ 106,832	$ 109,664	$ 114,457	$ 114,159	$ 102,865	$ 89,188	$ 488,318	$ 420,669	$ 415,955
Gross Profit		74,005	59,569	53,536	56,480	58,225	58,131	51,572	45,474	243,590	213,402	214,788
Net income (loss)		$ 27,278	$ 14,820	$ 13,192	$ 15,886	$ 158,291	$ 17,099	$ 10,845	$ 7,233	$ 71,176	$ 193,468	$ 69,984
Earnings per share
Basic | $ / shares		$ 0.46	$ 0.25	$ 0.22	$ 0.27	$ 2.69	$ 0.29	$ 0.19	$ 0.13	$ 1.19	$ 3.31	$ 1.19
Diluted | $ / shares		$ 0.45	$ 0.24	$ 0.22	$ 0.27	$ 2.64	$ 0.29	$ 0.19	$ 0.13	$ 1.17	$ 3.24	$ 1.16
Shares used in per share calculation
Basic | shares		59,879	59,823	59,712	59,204	58,854	58,770	58,594	57,902	59,657	58,534	58,912
Diluted | shares		61,176	60,852	60,624	60,268	60,010	59,732	59,404	58,892	60,845	59,632	60,294
Litigation settlement										$ 0	$ 168,969	$ 0
Stock split ratio	2