Investments (Gross Unrealized Losses and Fair Values of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	$ 66,783	$ 98,642
Available-for-sale securities, continuous unrealized loss position, less than 12 months, unrealized losses	435	2,063
Available-for-sale securities, continuous unrealized loss position, twelve months or longer, fair value	66,719	23,188
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, unrealized losses	6,246	7,767
Held-to-maturity securities, continuous unrealized loss position, less than twelve months, fair value	12,198	27,918
Held-to-maturity securities, continuous unrealized loss position, less than 12 months, unrealized loss	107	598
Held-to-maturity securities, continuous unrealized loss position, twelve months or longer, fair value	11,196	0
Held-to-maturity securities, continuous unrealized loss position, 12 months or longer, unrealized loss	244	0
US government agencies [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	4,977	24,253
Available-for-sale securities, continuous unrealized loss position, less than 12 months, unrealized losses	23	747
Available-for-sale securities, continuous unrealized loss position, twelve months or longer, fair value	24,501	0
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, unrealized losses	499	0
Residential mortgage-backed agencies [Member]
Schedule of Investments [Line Items]
Held-to-maturity securities, continuous unrealized loss position, less than twelve months, fair value	12,198	20,899
Held-to-maturity securities, continuous unrealized loss position, less than 12 months, unrealized loss	107	279
Held-to-maturity securities, continuous unrealized loss position, twelve months or longer, fair value	7,005	0
Held-to-maturity securities, continuous unrealized loss position, 12 months or longer, unrealized loss	194	0
Commercial mortgage-backed agencies [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	30,170	51,604
Available-for-sale securities, continuous unrealized loss position, less than 12 months, unrealized losses	233	757
Available-for-sale securities, continuous unrealized loss position, twelve months or longer, fair value	11,653	0
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, unrealized losses	361	0
Held-to-maturity securities, continuous unrealized loss position, less than twelve months, fair value		4,684
Held-to-maturity securities, continuous unrealized loss position, less than 12 months, unrealized loss		149
Held-to-maturity securities, continuous unrealized loss position, twelve months or longer, fair value		0
Held-to-maturity securities, continuous unrealized loss position, 12 months or longer, unrealized loss		0
Collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	28,222	14,706
Available-for-sale securities, continuous unrealized loss position, less than 12 months, unrealized losses	163	399
Available-for-sale securities, continuous unrealized loss position, twelve months or longer, fair value	13,009	0
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, unrealized losses	325	0
Held-to-maturity securities, continuous unrealized loss position, less than twelve months, fair value	0
Held-to-maturity securities, continuous unrealized loss position, less than 12 months, unrealized loss	0
Held-to-maturity securities, continuous unrealized loss position, twelve months or longer, fair value	4,191
Held-to-maturity securities, continuous unrealized loss position, 12 months or longer, unrealized loss	50
Obligations of states and political subdivisions [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	3,414	8,079
Available-for-sale securities, continuous unrealized loss position, less than 12 months, unrealized losses	16	160
Available-for-sale securities, continuous unrealized loss position, twelve months or longer, fair value	2,838	2,934
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, unrealized losses	60	91
Held-to-maturity securities, continuous unrealized loss position, less than twelve months, fair value	0	2,335
Held-to-maturity securities, continuous unrealized loss position, less than 12 months, unrealized loss	0	170
Held-to-maturity securities, continuous unrealized loss position, twelve months or longer, fair value	0	0
Held-to-maturity securities, continuous unrealized loss position, 12 months or longer, unrealized loss	0	0
Collateralized debt obligations [Member]
Schedule of Investments [Line Items]
Available-for-sale securities, continuous unrealized loss position, less than twelve months, fair value	0	0
Available-for-sale securities, continuous unrealized loss position, less than 12 months, unrealized losses	0	0
Available-for-sale securities, continuous unrealized loss position, twelve months or longer, fair value	14,718	20,254
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, unrealized losses	$ 5,001	$ 7,676

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)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27290-111563

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