INVESTMENTS (Summary of Amortized Cost and Fair Value of Debt and Equity Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt securities - available-for-sale:
Amortized Cost of Cost	$ 409,563	$ 473,126
Debt securities, at fair value	418,301	488,210
Debt Securities
Debt securities - available-for-sale:
Amortized Cost of Cost	409,563	473,126
Gross Unrealized Gains	10,422	15,218
Gross Unrealized Losses	1,684	134
Debt securities, at fair value	418,301	488,210
United States government obligations and authorities
Debt securities - available-for-sale:
Amortized Cost of Cost	122,895	169,947
Gross Unrealized Gains	1,190	1,866
Gross Unrealized Losses	457	38
Debt securities, at fair value	123,628	171,775
Obligations of states and political subdivisions
Debt securities - available-for-sale:
Amortized Cost of Cost	21,410	21,560
Gross Unrealized Gains	650	704
Gross Unrealized Losses	57	0
Debt securities, at fair value	22,003	22,264
Corporate securities
Debt securities - available-for-sale:
Amortized Cost of Cost	234,179	254,618
Gross Unrealized Gains	8,105	11,989
Gross Unrealized Losses	1,104	79
Debt securities, at fair value	241,180	266,528
International securities
Debt securities - available-for-sale:
Amortized Cost of Cost	31,079	27,001
Gross Unrealized Gains	477	659
Gross Unrealized Losses	66	17
Debt securities, at fair value	$ 31,490	$ 27,643

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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