Note 2 - Significant Accounting Policies (Details Textual)	Dec. 31, 2020
Centerpoint [Member]
Noncontrolling Interest, Ownership Percentage by Parent	58.90%

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant