ACQUISITIONS AND FDIC INDEMNIFICATION ASSET: (Details Textual) (USD $)	12 Months Ended		54 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Aug. 16, 2013 drive-up_facility branch
Business Acquisition [Line Items]
Goodwill	$ 39,489,000	$ 39,489,000	$ 39,489,000
Reimbursements from the FDIC	(1,050,000)	(352,000)	(24,200,000)
Outstanding balance for reimbursement of losses	(74,000)	1,055,000	1,055,000	2,632,000
Net changes in losses and expenses added	79,000	1,225,000
Covered loans	7,300,000	18,500,000	18,500,000
Bank of America
Business Acquisition [Line Items]
Number of bank branches acquired					7
Number of drive-up facilities acquired					2
Cash and equivalents					177,700,000
Loans					1,900,000
Property, plant, and equipment					5,900,000
Customer related core deposit intangible assets					2,200,000
Deposits					189,300,000
Other liabilities					300,000
Goodwill					1,900,000
Goodwill recorded, which is expected to be tax deductable					1,900
First National Bank Of Danville
Business Acquisition [Line Items]
Losses on assets, threshold under loss-sharing agreement (up to $29 million)	$ 29,000,000
Percentage of losses to be reimbursed by the FDIC, on losses up to the threshold amount (percent)	80.00%
Percentage of losses to be reimbursed by the FDIC, on losses exceeding the threshold amount (percent)	95.00%