Financial Instruments with Off-Balance Sheet Risk (Details) $ in Millions	Sep. 30, 2017 USD ($)
Unused commitments to extend credit
Financial Instruments with Off-Balance Sheet Risk
Outstanding commitments	$ 2,000.0
Standby letters of credit
Financial Instruments with Off-Balance Sheet Risk
Outstanding commitments	$ 28.8

The fair value of financial liabilities, which are not recognized in the financial statements (off-balance sheet) because they fail to meet some other criterion for recognition.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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