SIGNIFICANT ACCOUNTING POLICIES (Impact of statements of income, cash flows, and balance sheets after ASC 606) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Jun. 30, 2016
Statements of operations
Revenues	$ 239,997	$ 937,237	$ 607,045	$ 489,843
Financial expenses (income), net	2,789	2,297	(9,158)	(471)
Net income	25,381	128,833	84,172	76,609
Cash flows
Net income	25,381	128,833	84,172	76,609
Changes in assets and liabilities:
Deferred revenues	1,335	37,041	14,106	$ 8,578
Balance Sheets
Deferred Revenues - Current	1,202	14,351	2,559
Deferred Revenues - Long term	18,660	60,670	31,453
Retained earnings	$ (18,000)	191,133	$ 66,172
As Reported [Member]
Statements of operations
Revenues		937,237
Financial expenses (income), net		(2,297)
Net income		128,046
Cash flows
Net income		128,046
Changes in assets and liabilities:
Deferred revenues		37,041
Balance Sheets
Deferred Revenues - Current		14,351
Deferred Revenues - Long term		60,670
Retained earnings		191,133
Balances before adoption of ASC 606 [Member]
Statements of operations
Revenues		937,168
Financial expenses (income), net		122
Net income		130,396
Cash flows
Net income		130,396
Changes in assets and liabilities:
Deferred revenues		34,789
Balance Sheets
Deferred Revenues - Current		14,559
Deferred Revenues - Long term		54,240
Retained earnings		195,005
Effect of change [Member]
Statements of operations
Revenues		69
Financial expenses (income), net		(2,419)
Net income		(2,350)
Cash flows
Net income		(2,350)
Changes in assets and liabilities:
Deferred revenues		2,252
Balance Sheets
Deferred Revenues - Current		(208)
Deferred Revenues - Long term		6,430
Retained earnings		$ (3,872)