Securities (Details) - Narrative - USD ($)	Jun. 30, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Available-for-sale securities pledged as collateral	$ 1,100,000,000	$ 856,900,000
Held-to-maturity securities pledged as collateral	$ 0	$ 0

The carrying amount of held-to-maturity securities that serve as collateral for borrowings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5086-111524

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