Deposits - Remaining maturity of time deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deposits Liabilities, Balance Sheet, Reported Amounts [Abstract]
Three months or less	$ 201,312	$ 260,028
More than three months through twelve months	325,329	538,352
Over twelve months	451,119	484,659
Total	$ 977,760	$ 1,283,039

Amount of time deposit liabilities, including certificates of deposit.

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

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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