Note 12 - Regulatory Capital and Oversight (Details Textual) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
Sep. 30, 2016	Dec. 31, 2019
Scenario, Forecast [Member]
Capital Conservation Buffer		2.50%
Banks Tangible Assets	$ 667.9
Adjusted Assets	663.7
Risk Weighted Assets	$ 579.7
Capital Conservation Buffer	0.625%

Percentage of common equity tier 1 capital above its minimum risk-based capital requirements in order to avoid limitations on capital distributions, including dividend payments and certain discretionary bonus payments to executive officers.

No definition available.

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Namespace Prefix:	hmnf_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration