Borrowings - Maturity period (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Maturity period
Federal Funds Purchased	$ 0	$ 0
Maximum maturity period of short-term debt	1 year

Amount of short term borrowing where a bank borrows, at the federal funds rate, from another bank.

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 210.9-03.13(1))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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