Investment Securities - Unrealized losses (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities
Less than 12 Months, Fair Value	$ 188,167	$ 283,243
12 Months or More, Fair Value	74,586	18,104
Total Fair Value	262,753	301,347
Less than 12 Months, Unrealized Losses	(2,225)	(8,501)
12 Months or More, Unrealized Losses	(2,195)	(261)
Total Unrealized Losses	(4,420)	(8,762)
U.S. Government agencies
Schedule of Available-for-sale Securities
Less than 12 Months, Fair Value	8,201	34,586
12 Months or More, Fair Value	6,741	10,438
Total Fair Value	14,942	45,024
Less than 12 Months, Unrealized Losses	(47)	(198)
12 Months or More, Unrealized Losses	(27)	(79)
Total Unrealized Losses	(74)	(277)
Obligations of states and political subdivisions
Schedule of Available-for-sale Securities
Less than 12 Months, Fair Value	1,627	122,522
12 Months or More, Fair Value	3,357	0
Total Fair Value	4,984	122,522
Less than 12 Months, Unrealized Losses	(3)	(4,353)
12 Months or More, Unrealized Losses	(87)	0
Total Unrealized Losses	(90)	(4,353)
U.S. Government sponsored entities and agencies collateralized by residential mortgage obligations
Schedule of Available-for-sale Securities
Less than 12 Months, Fair Value	82,604	118,719
12 Months or More, Fair Value	64,488	7,666
Total Fair Value	147,092	126,385
Less than 12 Months, Unrealized Losses	(822)	(3,866)
12 Months or More, Unrealized Losses	(2,081)	(182)
Total Unrealized Losses	(2,903)	(4,048)
Private label residential mortgage and asset backed securities
Schedule of Available-for-sale Securities
Less than 12 Months, Fair Value	88,312
12 Months or More, Fair Value	0
Total Fair Value	88,312
Less than 12 Months, Unrealized Losses	(1,276)
12 Months or More, Unrealized Losses	0
Total Unrealized Losses	(1,276)
Other equity securities
Schedule of Available-for-sale Securities
Less than 12 Months, Fair Value	7,423	7,416
12 Months or More, Fair Value	0	0
Total Fair Value	7,423	7,416
Less than 12 Months, Unrealized Losses	(77)	(84)
12 Months or More, Unrealized Losses	0	0
Total Unrealized Losses	$ (77)	$ (84)

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

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