Investment Securities Held to Maturity (Details) $ in Thousands	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		$ 301,876	$ 327,268
Equity Securities	$ 1,802	0	0
Gross Unrealized Gains		935	1,617
Held-to-Maturity at Amortized Cost	297,885	335,907	348,018
Held-To-Maturity Securities, at Fair Value	292,605	335,901	350,355
Gross Unrealized Gains	497	1,960	3,885
Gross Unrealized Losses	5,777	1,966	1,548
Held-To-Maturity Securities, Pledged as Collateral	278,627	318,622	327,820
Maturities of Debt Securities, at Amortized Cost:
Within One Year	26,037
From 1 - 5 Years	137,369
From 5 - 10 Years	131,808
Over 10 Years	2,671
Maturities of Debt Securities, at Fair Value:
Within One Year	26,092
From 1 - 5 Years	136,084
From 5 - 10 Years	127,762
Over 10 Years	2,667
Securities in a Continuous Loss Position, at Fair Value:
Less than 12 Months	118,589	69,412	97,384
12 Months or Longer	93,735	68,409	403
Total	$ 212,324	$ 137,821	$ 97,787
Number of Securities in a Continuous Loss Position	512	366	272
Unrealized Losses on Securities in a Continuous Loss Position:
Less than 12 Months	$ 1,654	$ 498	$ 1,546
12 Months or Longer	4,123	1,468	2
Total	5,777	1,966	1,548
State and Municipal Obligations
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		10,351	15,410
Gross Unrealized Gains		9	31
Held-to-Maturity at Amortized Cost	244,016	275,530	280,485
Held-To-Maturity Securities, at Fair Value	239,841	275,353	282,157
Gross Unrealized Gains	497	1,691	3,208
Gross Unrealized Losses	4,672	1,868	1,536
Maturities of Debt Securities, at Amortized Cost:
Within One Year	26,037
From 1 - 5 Years	91,235
From 5 - 10 Years	124,073
Over 10 Years	2,671
Maturities of Debt Securities, at Fair Value:
Within One Year	26,092
From 1 - 5 Years	90,877
From 5 - 10 Years	120,206
Over 10 Years	2,667
Securities in a Continuous Loss Position, at Fair Value:
Less than 12 Months	68,612	55,648	93,046
12 Months or Longer	90,948	65,152	403
Total	$ 159,560	$ 120,800	$ 93,449
Number of Securities in a Continuous Loss Position	465	352	263
Unrealized Losses on Securities in a Continuous Loss Position:
Less than 12 Months	$ 633	$ 442	$ 1,534
12 Months or Longer	4,039	1,425	2
Total	4,672	1,867	1,536
Mortgage-Backed Securities - Residential
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		229,077	161,324
Gross Unrealized Gains		485	964
Held-to-Maturity at Amortized Cost	53,869	60,377	67,533
Held-To-Maturity Securities, at Fair Value	52,764	60,548	68,198
Gross Unrealized Gains	0	269	677
Gross Unrealized Losses	1,105	98	12
Maturities of Debt Securities, at Amortized Cost:
Within One Year	0
From 1 - 5 Years	46,134
From 5 - 10 Years	7,735
Over 10 Years	0
Maturities of Debt Securities, at Fair Value:
Within One Year	0
From 1 - 5 Years	45,207
From 5 - 10 Years	7,556
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value:
Less than 12 Months	49,977	13,764	4,338
12 Months or Longer	2,787	3,257	0
Total	$ 52,764	$ 17,021	$ 4,338
Number of Securities in a Continuous Loss Position	47	14	9
Unrealized Losses on Securities in a Continuous Loss Position:
Less than 12 Months	$ 1,021	$ 56	$ 12
12 Months or Longer	84	43	0
Total	1,105	99	12
Mortgage-Backed Securities - Residential | Agency Securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity at Amortized Cost	3,265	2,680	3,106
Mortgage-Backed Securities - Residential | US Government-sponsored Enterprises Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity at Amortized Cost	50,604	57,697	64,427
Corporate and Other Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		1,000	2,500
Gross Unrealized Gains		0	0
Held-to-Maturity at Amortized Cost	0	0	0
Held-To-Maturity Securities, at Fair Value	0	0	0
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	0	0
Maturities of Debt Securities, at Amortized Cost:
Within One Year	0
From 1 - 5 Years	0
From 5 - 10 Years	0
Over 10 Years	0
Maturities of Debt Securities, at Fair Value:
Within One Year	0
From 1 - 5 Years	0
From 5 - 10 Years	0
Over 10 Years	0
Securities in a Continuous Loss Position, at Fair Value:
Less than 12 Months	0	0	0
12 Months or Longer	0	0	0
Total	$ 0	$ 0	$ 0
Number of Securities in a Continuous Loss Position	0	0	0
Unrealized Losses on Securities in a Continuous Loss Position:
Less than 12 Months	$ 0	$ 0	$ 0
12 Months or Longer	0	0	0
Total	0	0	0
Fair Value, Measurements, Recurring
Schedule of Held-to-maturity Securities [Line Items]
Equity Securities	1,802
Fair Value, Measurements, Recurring | Mortgage-Backed Securities - Residential | US Government-sponsored Enterprises Debt Securities
Schedule of Held-to-maturity Securities [Line Items]
Held-To-Maturity Securities, at Fair Value	50,418	57,887	65,077
Agency Securities | Mortgage-Backed Securities - Residential
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis		40,832	3,740
Agency Securities | Fair Value, Measurements, Recurring | Mortgage-Backed Securities - Residential
Schedule of Held-to-maturity Securities [Line Items]
Held-To-Maturity Securities, at Fair Value	$ 2,346	$ 2,661	$ 3,121