Securities Sold Under Agreements to Repurchase Securities Sold Under Agreements to Repurchase (Details Textual) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Securities Sold Under Agreements to Repurchase
Repurchase Agreements	$ 453,596,000	$ 473,650,000
Securities Pledged for Repurchase Agreements	$ 528,791,000	$ 472,239,000

Amount, before effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and elected not to be offset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Name:	us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseGrossIncludingNotSubjectToMasterNettingArrangement
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant