AFS Securities (Amortized cost and fair value of AFS securities, with gross unrealized gains and losses) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 495,299	$ 501,245
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4,063	2,272
Gross Unrealized Losses	4,520	8,683
AFS securities	494,842	494,834
Government sponsored enterprises [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	166	172
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Gross Unrealized Losses	1	2
AFS securities	165	170
States and political subdivisions [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	187,716	188,992
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	3,566	2,125
Gross Unrealized Losses	16	251
AFS securities	191,266	190,866
Auction rate money market preferred [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	3,200	3,200
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Gross Unrealized Losses	381	646
AFS securities	2,819	2,554
Mortgage-backed securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	183,695	189,688
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	286	76
Gross Unrealized Losses	2,843	5,280
AFS securities	181,138	184,484
Collateralized mortgage obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	120,522	119,193
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	211	71
Gross Unrealized Losses	1,279	2,504
AFS securities	$ 119,454	$ 116,760

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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=109979856&loc=d3e26610-111562

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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