Mortgage Servicing Rights (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Mortgage Banking [Abstract]
Servicing Asset at Amortized Cost	$ 21,945,000	$ 20,415,000	$ 19,351,000	$ 16,688,000

Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7524895&loc=d3e120260-111741

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122492-111745

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122739-111746

Name:	us-gaap_ServicingAssetAtAmortizedValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant