Investment Securities, Available-for-sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	$ 529,532	$ 580,705
Gross Unrealized Gains	53	121
Gross Unrealized Losses	21,703	8,861
Fair Value	507,882	571,965
U. S. Government Sponsored Enterprises [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	154,866	139,890
Gross Unrealized Gains	0	27
Gross Unrealized Losses	4,813	2,066
Fair Value	150,053	137,851
State and Political Subdivisions [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	174	515
Gross Unrealized Gains	6	10
Gross Unrealized Losses	0	0
Fair Value	180	525
Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	282,286	330,424
Gross Unrealized Gains	47	84
Gross Unrealized Losses	13,240	4,825
Fair Value	269,093	325,683
Corporate Bonds [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	30,090	40,270
Gross Unrealized Gains	0	0
Gross Unrealized Losses	113	108
Fair Value	29,977	40,162
Small Business Administration-Guaranteed Participation Securities [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	61,431	68,921
Gross Unrealized Gains	0	0
Gross Unrealized Losses	3,537	1,862
Fair Value	57,894	67,059
Other [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	685	685
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 685	$ 685

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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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).

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+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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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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