FAIR VALUES OF FINANCIAL INSTRUMENTS: (Details 4) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Carrying amount and estimated fair value of financial instruments
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 13,995	$ 14,050	$ 14,079	$ 14,983
Securities available-for-sale	891,082	897,053
Restricted Stock	10,838	16,404
Accrued interest receivable	11,733	11,593
Deposits	(2,442,369)	(2,457,197)
Level 1
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	19,715	22,597
Securities available-for-sale	0	0
Level 2
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	68,980	55,505
Federal funds sold	9,815	8,000
Securities available-for-sale	871,482	875,850
Accrued interest receivable	3,366	3,183
Deposits	(2,442,612)	(2,459,703)
Short-term borrowings	(33,831)	(48,015)
Federal Home Loan Bank advances	(12,971)	(13,605)
Accrued interest payable	(389)	(456)
Level 3
Carrying amount and estimated fair value of financial instruments
Securities available-for-sale	19,600	21,203
Loans, net	1,789,938	1,810,885
Accrued interest receivable	8,367	8,410
Reported Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	88,695	78,102
Federal funds sold	9,815	8,000
Securities available-for-sale	891,082	897,053
Restricted Stock	10,838	16,404
Loans, net	1,743,862	1,762,589
Accrued interest receivable	11,733	11,593
Deposits	(2,442,369)	(2,457,197)
Short-term borrowings	(33,831)	(48,015)
Federal Home Loan Bank advances	(12,677)	(12,886)
Accrued interest payable	(389)	(456)
Estimate of Fair Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	88,695	78,102
Federal funds sold	9,815	8,000
Securities available-for-sale	891,082	897,053
Loans, net	1,789,938	1,810,885
Accrued interest receivable	11,733	11,593
Deposits	(2,442,612)	(2,459,703)
Short-term borrowings	(33,831)	(48,015)
Federal Home Loan Bank advances	(12,971)	(13,605)
Accrued interest payable	$ (389)	$ (456)

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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