SEGMENT INFORMATION (Schedule of Reportable Segments and Operating Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 331,851	$ 325,010	$ 763,069	$ 596,881
Cost of revenues	228,888	214,340	520,098	400,101
Gross profit	102,963	110,670	242,971	196,780
Research and development	38,098	29,505	74,793	55,704
Sales and marketing	20,936	22,127	45,189	42,299
General and administrative	13,964	13,685	30,149	25,376
Segment profit (loss)	36,668	32,913	78,916	50,888
Solar segment profit	54,590	66,212	142,560	111,042
All other segment loss	(7,906)	(5,174)	(17,230)	(8,801)
Segments operating profit	46,684	61,038	125,330	102,241
Amounts not allocated to segments:
Stock based compensation expenses	(13,961)	(11,372)	(26,734)	(21,076)
Amortization	(2,651)	(3,291)	(5,336)	(5,262)
Legal settlement (see Note 11)			4,900
Cost of products adjustments		(319)	(313)	(1,001)
Other unallocated expenses		(703)		(1,501)
Adjustments:
Intersegment profit	(107)		(107)
Consolidated operating income	29,965	45,353	97,740	73,401
Solar [Member]
Segment Reporting Information [Line Items]
Revenues	310,048	306,746	717,695	559,814
Cost of revenues	205,346	193,528	470,161	359,842
Gross profit	104,702	113,218	247,534	199,972
Research and development	26,374	22,280	53,457	42,512
Sales and marketing	15,020	17,149	33,643	32,349
General and administrative	8,718	7,577	17,874	14,069
Segment profit (loss)	54,590	66,212	142,560	111,042
All Other [Member]
Segment Reporting Information [Line Items]
Revenues	22,290	18,264	45,861	37,067
Cost of revenues	19,238	15,536	40,691	31,869
Gross profit	3,052	2,728	5,170	5,198
Research and development	5,852	3,039	10,060	5,481
Sales and marketing	2,179	2,307	4,322	4,017
General and administrative	2,927	2,556	8,018	4,501
Segment profit (loss)	$ (7,906)	$ (5,174)	$ (17,230)	$ (8,801)