Fair Value Measurements - Quantitative and Qualitative Information of Level 3 Fair Value Measurements (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Valuation techniques
Impaired loans	$ 3,631,000	$ 2,453,000
Level 3 \| Residential Real Estate
Valuation techniques
Impaired loans	$ 57,000
Non-recurring basis
Valuation techniques
Financial assets measured at fair value		$ 0

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953550-111524

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