Investment Securities (Held-to-maturity Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 42,163	$ 43,144
Gross Unrealized Gains	1,099	653
Gross Unrealized Losses	(454)	(570)
Held-to-maturity investment securities at fair value	42,808	43,227
States and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	3,812	3,820
Gross Unrealized Gains	651	221
Gross Unrealized Losses	0	0
Held-to-maturity investment securities at fair value	4,463	4,041
Residential mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	33,648	33,858
Gross Unrealized Gains	448	432
Gross Unrealized Losses	(406)	(528)
Held-to-maturity investment securities at fair value	33,690	33,762
Commercial mortgage-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	4,703	5,466
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(48)	(42)
Held-to-maturity investment securities at fair value	$ 4,655	$ 5,424