FAIR VALUES OF FINANCIAL INSTRUMENTS: (Details 4) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Carrying amount and estimated fair value of financial instruments
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 13,974	$ 13,995	$ 14,050	$ 14,079
Securities available-for-sale	853,725	891,082
Restricted Stock	10,359	10,838
Accrued interest receivable	12,311	11,733
Deposits	(2,428,526)	(2,442,369)
Level 1
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	21,047	19,715
Securities available-for-sale	0	0
Level 2
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	53,965	68,980
Federal funds sold	6,952	9,815
Securities available-for-sale	837,147	871,482
Accrued interest receivable	3,340	3,366
Deposits	(2,414,555)	(2,442,612)
Short-term borrowings	(80,989)	(33,831)
Federal Home Loan Bank advances	(137)	(12,971)
Accrued interest payable	(363)	(389)
Level 3
Carrying amount and estimated fair value of financial instruments
Securities available-for-sale	16,578	19,600
Loans, net	1,854,046	1,789,938
Accrued interest receivable	8,971	8,367
Reported Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	75,012	88,695
Federal funds sold	6,952	9,815
Securities available-for-sale	853,725	891,082
Restricted Stock	10,359	10,838
Loans, net	1,820,407	1,743,862
Accrued interest receivable	12,311	11,733
Deposits	(2,428,526)	(2,442,369)
Short-term borrowings	(80,989)	(33,831)
Federal Home Loan Bank advances	(132)	(12,677)
Accrued interest payable	(363)	(389)
Estimate of Fair Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	75,012	88,695
Federal funds sold	6,952	9,815
Securities available-for-sale	853,725	891,082
Loans, net	1,854,046	1,789,938
Accrued interest receivable	12,311	11,733
Deposits	(2,414,555)	(2,442,612)
Short-term borrowings	(80,989)	(33,831)
Federal Home Loan Bank advances	(137)	(12,971)
Accrued interest payable	$ (363)	$ (389)

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
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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