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Fair Value (Recorded amount of assets and liabilities measured at fair value) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
AFS Securities
AFS securities	$ 494,842	$ 494,834
Fair value, total	514,773	515,202
Level 1 [Member]
AFS Securities
Fair value, total	$ 0	$ 0
Percent of assets and liabilities measured at fair value	0.00%	0.00%
Level 2 [Member]
AFS Securities
Fair value, total	$ 495,085	$ 495,157
Percent of assets and liabilities measured at fair value	96.18%	96.11%
Level 3 [Member]
AFS Securities
Fair value, total	$ 19,688	$ 20,045
Percent of assets and liabilities measured at fair value	3.82%	3.89%
Recurring items [Member]
AFS Securities
AFS securities	$ 494,842	$ 494,834
Derivative instruments	(243)	323
Recurring items [Member] | Government sponsored enterprises [Member]
AFS Securities
AFS securities	165	170
Recurring items [Member] | States and political subdivisions [Member]
AFS Securities
AFS securities	191,266	190,866
Recurring items [Member] | Auction rate money market preferred [Member]
AFS Securities
AFS securities	2,819	2,554
Recurring items [Member] | Mortgage-backed securities [Member]
AFS Securities
AFS securities	181,138	184,484
Recurring items [Member] | Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	119,454	116,760
Recurring items [Member] | Level 1 [Member]
AFS Securities
AFS securities	0	0
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	494,842	494,834
Derivative instruments	243	323
Recurring items [Member] | Level 2 [Member] | Government sponsored enterprises [Member]
AFS Securities
AFS securities	165	170
Recurring items [Member] | Level 2 [Member] | States and political subdivisions [Member]
AFS Securities
AFS securities	191,266	190,866
Recurring items [Member] | Level 2 [Member] | Auction rate money market preferred [Member]
AFS Securities
AFS securities	2,819	2,554
Recurring items [Member] | Level 2 [Member] | Mortgage-backed securities [Member]
AFS Securities
AFS securities	181,138	184,484
Recurring items [Member] | Level 2 [Member] | Collateralized mortgage obligations [Member]
AFS Securities
AFS securities	119,454	116,760
Recurring items [Member] | Level 3 [Member]
AFS Securities
AFS 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)	19,688	20,045
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)	$ 19,688	$ 20,045

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-Publisher FASB
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-Topic 320
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