Securities - Amortized Cost and Fair Value, Available for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amortized cost and fair value of securities available for sale
Amortized Cost	$ 674,104	$ 686,405
Gross Unrealized Gains	7,872	3,908
Gross Unrealized Losses	(10,488)	(16,065)
Fair Value	671,488	674,248
Trust preferred securities
Amortized cost and fair value of securities available for sale
Amortized Cost	12,442	23,749
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3,054)	(5,360)
Fair Value	9,388	18,389
Other debt securities
Amortized cost and fair value of securities available for sale
Amortized Cost	17,106	22,053
Gross Unrealized Gains	260	310
Gross Unrealized Losses	(76)	(218)
Fair Value	17,290	22,145
Other equity securities
Amortized cost and fair value of securities available for sale
Amortized Cost		0
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		0
Obligations of other U.S. Government agencies and corporations
Amortized cost and fair value of securities available for sale
Amortized Cost	3,554	2,066
Gross Unrealized Gains	40	92
Gross Unrealized Losses	(30)	0
Fair Value	3,564	2,158
Obligations of states and political subdivisions
Amortized cost and fair value of securities available for sale
Amortized Cost	228,589
Gross Unrealized Gains	6,161
Gross Unrealized Losses	(269)
Fair Value	234,481
Government agency mortgage backed securities \| Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	196,121	414,019
Gross Unrealized Gains	888	1,941
Gross Unrealized Losses	(3,059)	(6,643)
Fair Value	193,950	409,317
Government agency mortgage backed securities \| Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	31,015	50,628
Gross Unrealized Gains	389	696
Gross Unrealized Losses	(234)	(461)
Fair Value	31,170	50,863
Government agency collateralized mortgage obligations \| Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	180,258	171,362
Gross Unrealized Gains	133	831
Gross Unrealized Losses	(3,752)	(3,367)
Fair Value	176,639	168,826
Government agency collateralized mortgage obligations \| Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	5,019	2,528
Gross Unrealized Gains	1	38
Gross Unrealized Losses	(14)	(16)
Fair Value	$ 5,006	$ 2,550

This item represents the cost of debt 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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-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

Reference 2: 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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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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
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-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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