Comprehensive Income (Details) - Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
COMPREHENSIVE INCOME (Details) - Comprehensive Income (Loss) [Line Items]
Sale of investment securities available-for-sale Net gains on sale investment securities	$ (1,350)	$ (5,624)	$ (2,991)
Sale of investment securities available-for-sale Income tax expense	(532)	(2,142)	(1,196)
Total reclassification	(1,173)	1,763	(3,595)
Reclassification out of Accumulated Other Comprehensive Income [Member]
COMPREHENSIVE INCOME (Details) - Comprehensive Income (Loss) [Line Items]
Sale of investment securities available-for-sale Net gains on sale investment securities	1,596	4,234	3,931
Sale of investment securities available-for-sale Income tax expense	(579)	(1,682)	(1,564)
Sale of investment securities available-for-sale	1,017	2,552	2,367
Amortization of unrealized holding (losses) gains on securities transferred from available-for-sale to held-to-maturity Interest income		(1,986)	(220)
Amortization of unrealized holding (losses) gains on securities transferred from available-for-sale to held-to-maturity Income tax benefit		813	90
Amortization of unrealized holding (losses) gains on securities transferred from available-for-sale to held-to-maturity		(1,173)	(130)
Amortization of pension plan net actuarial losses Salaries and employee benefits	(412)	(407)	(443)
Amortization of pension plan net actuarial losses Income tax benefit	169	165	177
Amortization of pension plan net actuarial losses	(243)	(242)	(256)
Total reclassification	$ 774	$ 1,137	$ 1,981