FAIR VALUES OF FINANCIAL INSTRUMENTS: (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair value measurement
Securities available-for-sale	$ 784,916	$ 814,931
U.S. Government entity mortgage-backed securities
Fair value measurement
Securities available-for-sale	25,364	13,695
Mortgage-backed securities, residential
Fair value measurement
Securities available-for-sale	178,743	215,338
Mortgage-backed securities, commercial
Fair value measurement
Securities available-for-sale	0	1
Collateralized mortgage obligations
Fair value measurement
Securities available-for-sale	343,616	339,670
State and municipal obligations
Fair value measurement
Securities available-for-sale	233,935	231,622
Collateralized debt obligations
Fair value measurement
Securities available-for-sale	3,258	14,605
Level 1
Fair value measurement
Securities available-for-sale	0	0
Level 2
Fair value measurement
Securities available-for-sale	778,523	796,646
Derivative Assets	218	298
Derivative Liabilities	(218)	(298)
Level 2 \| U.S. Government entity mortgage-backed securities
Fair value measurement
Securities available-for-sale	25,364	13,695
Level 2 \| Mortgage-backed securities, residential
Fair value measurement
Securities available-for-sale	178,743	215,338
Level 2 \| Mortgage-backed securities, commercial
Fair value measurement
Securities available-for-sale	0	1
Level 2 \| Collateralized mortgage obligations
Fair value measurement
Securities available-for-sale	343,616	339,670
Level 2 \| State and municipal obligations
Fair value measurement
Securities available-for-sale	230,800	227,942
Level 3
Fair value measurement
Securities available-for-sale	6,393	18,285
Level 3 \| State and municipal obligations
Fair value measurement
Securities available-for-sale	3,135	3,680
Level 3 \| Collateralized debt obligations
Fair value measurement
Securities available-for-sale	$ 3,258	$ 14,605

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
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