Investment Securities, Available-for-sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	$ 574,983	$ 580,705
Gross Unrealized Gains	85	121
Gross Unrealized Losses	15,985	8,861
Fair Value	559,083	571,965
U. S. Government Sponsored Enterprises [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	154,861	139,890
Gross Unrealized Gains	0	27
Gross Unrealized Losses	3,534	2,066
Fair Value	151,327	137,851
State and Political Subdivisions [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	515	515
Gross Unrealized Gains	10	10
Gross Unrealized Losses	0	0
Fair Value	525	525
Corporate Bonds [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	35,347	40,270
Gross Unrealized Gains	0	0
Gross Unrealized Losses	120	108
Fair Value	35,227	40,162
Mortgage Backed Securities and Collateralized Mortgage Obligations-Residential [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	307,679	320,614
Gross Unrealized Gains	75	84
Gross Unrealized Losses	10,121	4,715
Fair Value	297,633	315,983
Small Business Administration-Guaranteed Participation Securities [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	66,153	68,921
Gross Unrealized Gains	0	0
Gross Unrealized Losses	2,040	1,862
Fair Value	64,113	67,059
Mortgage Backed Securities and Collateralized Mortgage Obligations-Commercial [Member]
Amortized cost and fair value of the securities available for sale [Abstract]
Amortized Cost	9,743	9,810
Gross Unrealized Gains	0	0
Gross Unrealized Losses	170	110
Fair Value	9,573	9,700
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 of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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 investments in debt and equity securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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