Loans - Allowance for credit loss activity - Additional Information (Details) $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($)
UCFC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Merger with UCFC	$ 25.9

Amount of addition to allowance reserve for credit loss arising from purchase of loan and lease portfolios.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Name:	us-gaap_AllowanceForLoanAndLeaseLossesLoansAcquired
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration