Investment Securities Held to Maturity Securities by Type (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	$ 384,909	$ 393,855
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	752	387
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(5,218)	(10,249)
Securities held to maturity, fair value	380,443	383,993
US Government Agencies Residential Mortgage-backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	3,606	3,635
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(26)	(97)
Securities held to maturity, fair value	3,580	3,538
US Government Agency Debt Securities Commercial [Domain]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	54,898	55,221
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(1,763)	(2,327)
Securities held to maturity, fair value	53,135	52,894
Residential Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	270,807	279,109
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	352	212
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(3,303)	(7,254)
Securities held to maturity, fair value	267,856	272,067
Obligations of U.S. Government-Sponsored Enterprises - Mortgage-Backed Securities - Commercial [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	12,894	13,159
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(95)	(258)
Securities held to maturity, fair value	12,799	12,901
Obligations of States and Political Subdivisions [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	42,304	42,331
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	400	175
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	(31)	(313)
Securities held to maturity, fair value	42,673	42,193
Debt Security, Government, Non-US [Member]
Schedule of Held-to-maturity Securities [Line Items]
Debt Securities, Held-to-maturity	400	400
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0	0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Loss	0	0
Securities held to maturity, fair value	$ 400	$ 400

Amount of investment in debt security measured at amortized cost (held-to-maturity).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26610-111562

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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Amount of accumulated unrealized loss on investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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Fair value of investment in debt security measured at amortized cost (held-to-maturity).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27232-111563

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