Securities Available-for-Sale (Details) - Investments classified by maturity date - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Investment Securities Available-for-Sale:
Due in one year or less, amortized cost	$ 6,817
Due in one year or less, fair value	6,810
Due after one year through five years, amortized cost	33,357
Due after one year through five years, fair value	33,125
Due after five years through ten years, amortized cost	31,599
Due after five years through ten years, fair value	31,918
Due after ten years, amortized cost	145,811
Due after ten years, fair value	142,094
Total, amortized cost	408,282	$ 436,868
Total, fair value	400,015
Residential mortgage pass-through securities [Member]
Investment Securities Available-for-Sale:
Total, amortized cost	184,639	183,509
Total, fair value	180,103
Commercial mortgage pass-through securities [Member]
Investment Securities Available-for-Sale:
Total, amortized cost	3,987	4,054
Total, fair value	3,893
Other securities [Member]
Investment Securities Available-for-Sale:
Total, amortized cost	2,072	$ 3,422
Total, fair value	$ 2,072