Fair Value (Recorded amount of assets and liabilities measured at fair value) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
AFS Securities
AFS securities	$ 501,139	$ 548,730
Available-for-sale Securities, Equity Securities	0	3,577
Fair value, total	530,870	568,554
Level 1 [Member]
AFS Securities
Fair value, total	$ 0	$ 3,577
Percent of assets and liabilities measured at fair value	0.00%	0.63%
Level 2 [Member]
AFS Securities
Fair value, total	$ 501,590	$ 549,021
Percent of assets and liabilities measured at fair value	94.48%	96.56%
Level 3 [Member]
AFS Securities
Fair value, total	$ 29,280	$ 15,956
Percent of assets and liabilities measured at fair value	5.52%	2.81%
Recurring items [Member]
AFS Securities
AFS securities	$ 501,139	$ 548,730
Available-for-sale Securities, Equity Securities	0	3,577
Derivative instruments	(451)	291
Recurring items [Member] \| Government sponsored enterprises [Member]
AFS Securities
AFS securities	180	216
Recurring items [Member] \| States and political subdivisions [Member]
AFS Securities
AFS securities	193,957	208,474
Recurring items [Member] \| Auction rate money market preferred [Member]
AFS Securities
AFS securities	3,108	3,049
Recurring items [Member] \| Mortgage-backed securities [Member]
AFS Securities
AFS securities	188,136	208,797
Recurring items [Member] \| Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	115,758	128,194
Recurring items [Member] \| Level 1 [Member]
AFS Securities
AFS securities	0	0
Available-for-sale Securities, Equity Securities	0	3,577
Derivative instruments	0	0
Recurring items [Member] \| Level 1 [Member] \| Government sponsored enterprises [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 1 [Member] \| States and political subdivisions [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 1 [Member] \| Auction rate money market preferred [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 1 [Member] \| Mortgage-backed securities [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 1 [Member] \| Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 2 [Member]
AFS Securities
AFS securities	501,139	548,730
Available-for-sale Securities, Equity Securities	0	0
Derivative instruments	451	291
Recurring items [Member] \| Level 2 [Member] \| Government sponsored enterprises [Member]
AFS Securities
AFS securities	180	216
Recurring items [Member] \| Level 2 [Member] \| States and political subdivisions [Member]
AFS Securities
AFS securities	193,957	208,474
Recurring items [Member] \| Level 2 [Member] \| Auction rate money market preferred [Member]
AFS Securities
AFS securities	3,108	3,049
Recurring items [Member] \| Level 2 [Member] \| Mortgage-backed securities [Member]
AFS Securities
AFS securities	188,136	208,797
Recurring items [Member] \| Level 2 [Member] \| Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	115,758	128,194
Recurring items [Member] \| Level 3 [Member]
AFS Securities
AFS securities	0	0
Available-for-sale Securities, Equity Securities	0	0
Derivative instruments	0	0
Recurring items [Member] \| Level 3 [Member] \| Government sponsored enterprises [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 3 [Member] \| States and political subdivisions [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 3 [Member] \| Auction rate money market preferred [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 3 [Member] \| Mortgage-backed securities [Member]
AFS Securities
AFS securities	0	0
Recurring items [Member] \| Level 3 [Member] \| Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	0	0
Nonrecurring items [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	29,280	15,956
Nonrecurring items [Member] \| Level 1 [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	0	0
Nonrecurring items [Member] \| Level 2 [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	0	0
Nonrecurring items [Member] \| Level 3 [Member]
AFS Securities
Impaired loans (net of the allowance for loan losses)	$ 29,280	$ 15,956

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Percent of assets and liabilities measured at fair value.

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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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
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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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