Stock awards (Details 2) - Board of Directors - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based compensation arrangement by share-based payment award [Line Items]
Share-based Compensation Arrangement Shares Issued in Period	41,925	45,273	41,644
Share-based Compensation Arrangement, Value	$ 1.2	$ 1.1	$ 1.2

Number of shares issued under share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration