PARENT COMPANY FINANCIAL INFORMATION - CONDENSED STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 3,617	$ 3,106	$ 3,003	$ 3,246	$ 3,654	$ 2,896	$ 2,968	$ 2,964	$ 12,972	$ 12,482	$ 11,474
Cash flows from investing activities:
Proceeds from sales of available-for-sale securities									43,246	92,455	97,981
Cash flows from financing activities:
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR				18,865					18,865
CASH AND CASH EQUIVALENTS AT END OF YEAR	25,386				18,865				25,386	18,865
Parent Company
Cash flows from operating activities:
Net income									12,972	12,482	11,474
Adjustments for non-cash items -
Increase in undistributed income of subsidiaries									(7,032)	(5,814)	(6,528)
Other, net									84	126	42
NET CASH FLOWS PROVIDED BY OPERATING ACTIVITIES									6,024	6,794	4,988
Cash flows from investing activities:
Purchases of securities available-for-sale									(54)	(177)	(215)
Available-for-sale									50	55	0
Proceeds from sales of available-for-sale securities									43	173	1,217
Payments to Acquire Interest in Subsidiaries and Affiliates									(250)	0	0
Cash paid for business acquisition									0	0	(3,757)
NET CASH FLOWS PROVIDED BY (USED IN) INVESTING ACTIVITIES									(211)	51	(2,755)
Cash flows from financing activities:
Proceeds from issuance of common stock									360	379	390
Repurchase of stock warrants									0	(1,545)	0
Cash dividends paid on common stock									(6,407)	(6,375)	(6,239)
Other									51	653	165
NET CASH FLOWS PROVIDED BY (USED IN) FINANCING ACTIVITIES									(5,996)	(6,888)	(5,684)
NET CHANGE IN CASH AND CASH EQUIVALENTS									(183)	(43)	(3,451)
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR				$ 491				$ 534	491	534	3,985
CASH AND CASH EQUIVALENTS AT END OF YEAR	$ 308				$ 491				$ 308	$ 491	$ 534