Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Comprehensive Income [Abstract]
Net income (loss)	$ (29)	$ 3,797	$ 3,634
Other comprehensive income (loss), net of tax
Net unrealized gain (loss) on available-for-sale securities	1,032	(1,163)	(498)
Amortization of unrealized losses on securities transferred to held-to-maturity	0	0	3,386
Changes in defined benefit plan assets and benefit obligations	2,469	117	(157)
Other comprehensive income (loss), net of tax	3,501	(1,046)	2,731
Comprehensive income	$ 3,472	$ 2,751	$ 6,365