Investment Securities - Held-to-Maturity and Available-for-Sale, Scheduled Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Held-to-maturity Securities [Abstract]
Securities Held-to-Maturity, Amortized Cost	$ 55,564	$ 24,881
Securities Held-to-Maturity, Gross Unrealized Gains	44	2
Securities Held-to-Maturity, Gross Unrealized Losses	(288)	(12)
Securities Held-to-Maturity, Fair Value	55,320	24,871
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost	404,766	451,311
Securities Available-for-Sale, Gross Unrealized Gains	1,822	1,777
Securities Available-for-Sale, Gross Unrealized Losses	(8,070)	(9,451)
Securities Available-for-Sale, Fair Value	398,518	443,637
U.S. Government Corporations and Agencies [Member]
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost, Within 1 year	1,499	15,000
Securities Available-for-Sale, Gross Unrealized Gains, Within 1 year	0	20
Securities Available-for-Sale, Gross Unrealized Losses, Within 1 year	(3)	0
Securities Available-for-Sale, Fair Value, Within 1 year	1,496	15,020
Securities Available-for-Sale, Amortized Cost, After 1 year to 5 years	15,590	17,265
Securities Available-for-Sale, Gross Unrealized Gains, After 1 year to 5 years	0	0
Securities Available-for-Sale, Gross Unrealized Losses, After 1 year to 5 years	(125)	(19)
Securities Available-for-Sale, Fair Value, After 1 year to 5 years	15,465	17,246
Securities Available-for-Sale, Amortized Cost	17,089	32,265
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	20
Securities Available-for-Sale, Gross Unrealized Losses	(128)	(19)
Securities Available-for-Sale, Fair Value	16,961	32,266
State and Political Subdivisions [Member]
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost, Within 1 year	2,721	964
Securities Available-for-Sale, Gross Unrealized Gains, Within 1 year	1	0
Securities Available-for-Sale, Gross Unrealized Losses, Within 1 year	(6)	(1)
Securities Available-for-Sale, Fair Value, Within 1 year	2,716	963
Securities Available-for-Sale, Amortized Cost, After 1 year to 5 years	16,787	18,705
Securities Available-for-Sale, Gross Unrealized Gains, After 1 year to 5 years	33	38
Securities Available-for-Sale, Gross Unrealized Losses, After 1 year to 5 years	(44)	(75)
Securities Available-for-Sale, Fair Value, After 1 year to 5 years	16,776	18,668
Securities Available-for-Sale, Amortized Cost, After 5 years to 10 years	54,846	55,541
Securities Available-for-Sale, Gross Unrealized Gains, After 5 years to 10 years	897	829
Securities Available-for-Sale, Gross Unrealized Losses, After 5 years to 10 years	(73)	(426)
Securities Available-for-Sale, Fair Value, After 5 years to 10 years	55,670	55,944
Securities Available-for-Sale, Amortized Cost, Over 10 years	3,120	12,663
Securities Available-for-Sale, Gross Unrealized Gains, Over 10 years	15	226
Securities Available-for-Sale, Gross Unrealized Losses, Over 10 years	0	(114)
Securities Available-for-Sale, Fair Value, Over 10 years	3,135	12,775
Securities Available-for-Sale, Amortized Cost	77,474	87,873
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	946	1,093
Securities Available-for-Sale, Gross Unrealized Losses	(123)	(616)
Securities Available-for-Sale, Fair Value	78,297	88,350
Residential Mortgage Backed Securities [Member]
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost, After 1 year to 5 years	3,913	6,086
Securities Available-for-Sale, Gross Unrealized Gains, After 1 year to 5 years	12	0
Securities Available-for-Sale, Gross Unrealized Losses, After 1 year to 5 years	(26)	(66)
Securities Available-for-Sale, Fair Value, After 1 year to 5 years	3,899	6,020
Securities Available-for-Sale, Amortized Cost, After 5 years to 10 years	51,428	23,479
Securities Available-for-Sale, Gross Unrealized Gains, After 5 years to 10 years	5	0
Securities Available-for-Sale, Gross Unrealized Losses, After 5 years to 10 years	(852)	(622)
Securities Available-for-Sale, Fair Value, After 5 years to 10 years	50,581	22,857
Securities Available-for-Sale, Amortized Cost, Over 10 years	133,237	174,388
Securities Available-for-Sale, Gross Unrealized Gains, Over 10 years	87	99
Securities Available-for-Sale, Gross Unrealized Losses, Over 10 years	(2,383)	(4,794)
Securities Available-for-Sale, Fair Value, Over 10 years	130,941	169,693
Securities Available-for-Sale, Amortized Cost	188,578	203,953
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	104	99
Securities Available-for-Sale, Gross Unrealized Losses	(3,261)	(5,482)
Securities Available-for-Sale, Fair Value	185,421	198,570
Collateralized Mortgage Obligations [Member]
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost, After 5 years to 10 years	2,103	0
Securities Available-for-Sale, Gross Unrealized Gains, After 5 years to 10 years	0	0
Securities Available-for-Sale, Gross Unrealized Losses, After 5 years to 10 years	(82)	0
Securities Available-for-Sale, Fair Value, After 5 years to 10 years	2,021	0
Securities Available-for-Sale, Amortized Cost, Over 10 years	1,567	4,659
Securities Available-for-Sale, Gross Unrealized Gains, Over 10 years	14	0
Securities Available-for-Sale, Gross Unrealized Losses, Over 10 years	0	(105)
Securities Available-for-Sale, Fair Value, Over 10 years	1,581	4,554
Securities Available-for-Sale, Amortized Cost	3,670	4,659
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	14	0
Securities Available-for-Sale, Gross Unrealized Losses	(82)	(105)
Securities Available-for-Sale, Fair Value	3,602	4,554
Corporate Bonds [Member]
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost, Within 1 year	10,006	250
Securities Available-for-Sale, Gross Unrealized Gains, Within 1 year	0	0
Securities Available-for-Sale, Gross Unrealized Losses, Within 1 year	(5)	0
Securities Available-for-Sale, Fair Value, Within 1 year	10,001	250
Securities Available-for-Sale, Amortized Cost, After 1 year to 5 years	24,885	35,923
Securities Available-for-Sale, Gross Unrealized Gains, After 1 year to 5 years	20	34
Securities Available-for-Sale, Gross Unrealized Losses, After 1 year to 5 years	(147)	(241)
Securities Available-for-Sale, Fair Value, After 1 year to 5 years	24,758	35,716
Securities Available-for-Sale, Amortized Cost, After 5 years to 10 years	16,669	15,193
Securities Available-for-Sale, Gross Unrealized Gains, After 5 years to 10 years	71	0
Securities Available-for-Sale, Gross Unrealized Losses, After 5 years to 10 years	(296)	(516)
Securities Available-for-Sale, Fair Value, After 5 years to 10 years	16,444	14,677
Securities Available-for-Sale, Amortized Cost, Over 10 years	60,000	60,000
Securities Available-for-Sale, Gross Unrealized Gains, Over 10 years	0	27
Securities Available-for-Sale, Gross Unrealized Losses, Over 10 years	(4,027)	(2,472)
Securities Available-for-Sale, Fair Value, Over 10 years	55,973	57,555
Securities Available-for-Sale, Amortized Cost	111,560	111,366
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	91	61
Securities Available-for-Sale, Gross Unrealized Losses	(4,475)	(3,229)
Securities Available-for-Sale, Fair Value	107,176	108,198
Money Market Mutual Funds [Member]
Available-for-sale Securities [Abstract]
Securities Available-for-Sale, Amortized Cost	5,985	10,784
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Securities Available-for-Sale, Gross Unrealized Losses	0	0
Securities Available-for-Sale, Fair Value	5,985	10,784
Equity Securities [Member]
Available-for-sale Securities [Abstract]
Equity Securities Available-for-Sale, Amortized Cost	410	411
Equity Securities Available-for-Sale, Gross Unrealized Gains	667	504
Equity Securities Available-for-Sale, Gross Unrealized Loss	(1)	0
Equity Securities Available-for-Sale, Fair Value	1,076	915
U.S. Government Corporations and Agencies [Member]
Held-to-maturity Securities [Abstract]
Securities Held-to-Maturity, Amortized Cost, After 1 year to 5 years	6,995	0
Securities Held-to-Maturity, Gross Unrealized Gains, After 1 year to 5 years	0	0
Securities Held-to-Maturity, Gross Unrealized Losses, After 1 year to 5 years	(77)	0
Securities Held-to-Maturity, Fair Value, After 1 year to 5 years	6,918	0
Securities Held-to-Maturity, Amortized Cost	6,995	0
Securities Held-to-Maturity, Gross Unrealized Gains	0	0
Securities Held-to-Maturity, Gross Unrealized Losses	(77)	0
Securities Held-to-Maturity, Fair Value	6,918	0
Residential Mortgage Backed Securities [Member]
Held-to-maturity Securities [Abstract]
Securities Held-to-maturity, Amortized Cost, After 5 years to 10 years	8,944	0
Securities Held-to-maturity, Gross Unrealized Gains, After 5 years to 10 years	0	0
Securities Held-to-maturity, Gross Unrealized Losses, After 5 years to 10 years	(51)	0
Securities Held-to-maturity, Fair Value, After 5 years to 10 years	8,893	0
Securities Held-to-Maturity, Amortized Cost, Over 10 years	39,625	5,071
Securities Held-to-Maturity, Gross Unrealized Gains, Over 10 years	44	0
Securities Held-to-Maturity, Gross Unrealized Losses, Over 10 years	(160)	(3)
Securities Held-to-Maturity, Fair Value, Over 10 years	39,509	5,068
Securities Held-to-Maturity, Amortized Cost	48,569	5,071
Securities Held-to-Maturity, Gross Unrealized Gains	44	0
Securities Held-to-Maturity, Gross Unrealized Losses	(211)	(3)
Securities Held-to-Maturity, Fair Value	48,402	5,068
Corporate Bonds [Member]
Held-to-maturity Securities [Abstract]
Securities Held-to-Maturity, Amortized Cost, Within 1 year	0	19,810
Securities Held-to-Maturity, Gross Unrealized Gains, Within 1 year	0	2
Securities Held-to-Maturity, Gross Unrealized Losses, Within 1 year	0	(9)
Securities Held-to-Maturity, Fair Value, Within 1 year	0	19,803
Securities Held-to-Maturity, Amortized Cost	0	19,810
Securities Held-to-Maturity, Gross Unrealized Gains	0	2
Securities Held-to-Maturity, Gross Unrealized Losses	0	(9)
Securities Held-to-Maturity, Fair Value	$ 0	$ 19,803