Deposits - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial Services, Banking and Thrift [Abstract]
Time deposits, $250,000 or more	$ 1,400.0	$ 1,700.0
Interest expense on time deposits of $250 thousand or more	4.5	5.8	$ 6.6
Deposits from certain directors, executive officers and their affiliates	$ 97.3	$ 67.1

Amount of deposits held by the entity for a related party (entity, shareholder, employee).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(k))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(k)(1))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

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