MARKETABLE SECURITIES (Schedule of amortized cost, unrealized gains and losses, and fair value of available-for-sale) (Details) - USD ($) $ in Thousands |
Dec. 31, 2021 |
Dec. 31, 2020 |
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|---|---|---|---|---|---|
| Marketable Securities [Line Items] | |||||
| Amortized cost | $ 501,377 | $ 395,960 | |||
| Gross unrealized losses | (1,747) | [1] | (132) | ||
| Gross unrealized gains | 965 | 3,218 | |||
| Fair value | 500,595 | 399,046 | |||
| Available-for-sale securities, continuous unrealized loss position for twelve months or longer | 16 | ||||
| Corporate debentures [Member] | |||||
| Marketable Securities [Line Items] | |||||
| Amortized cost | 453,927 | 354,775 | |||
| Gross unrealized losses | (1,493) | [1] | (115) | ||
| Gross unrealized gains | 881 | 3,004 | |||
| Fair value | 453,315 | 357,664 | |||
| Government debentures [Member] | |||||
| Marketable Securities [Line Items] | |||||
| Amortized cost | 47,450 | 41,185 | |||
| Gross unrealized losses | (254) | [1] | (17) | ||
| Gross unrealized gains | 84 | 214 | |||
| Fair value | $ 47,280 | $ 41,382 | |||
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