Deposits - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Banking and Thrift [Abstract]
Bank overdrafts classified as loans	$ 18.4	$ 9.6
Certificates of deposit in excess of FDIC insurance limit	$ 3,000.0	$ 782.4

Amount of deposits held by the entity that have been reclassified as loan balances receivable, for example, but not limited to, overdrafts receivable.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116652737&loc=d3e64164-112818

Name:	us-gaap_DepositLiabilitiesReclassifiedAsLoansReceivable1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant