Note 7 - Loans Receivable and Allowance for Loan Losses - Past Due Loans (Details) - USD ($)		Mar. 31, 2018	Mar. 31, 2017
Current		$ 380,780,116	$ 336,098,044
Past due		2,476,716	599,853
Nonaccrual loans		5,964,407	2,301,935
Loans		389,221,239	338,999,832
Nonaccrual interest not accrued		393,818	182,113
Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		1,037,360	504,192
Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		233,115	74,631
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		1,206,241	21,030
Real Estate Loans [Member]
Loans		309,465,974	293,721,660
Real Estate Loans [Member] | Residential [Member]
Nonaccrual loans		864,644	675,017
Nonaccrual interest not accrued		61,370	41,637
Real Estate Loans [Member] | Residential [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		752,982	69,618
Real Estate Loans [Member] | Residential [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		70,291	74,631
Real Estate Loans [Member] | Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Real Estate Loans [Member] | Investor Loans [Member]
Nonaccrual loans		361,821	71,107
Nonaccrual interest not accrued		24,117	30,275
Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due			320,971
Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		1,206,241	21,030
Real Estate Loans [Member] | Commercial [Member]
Nonaccrual loans		4,555,202	1,546,812
Loans		112,166,254	107,564,212
Nonaccrual interest not accrued		294,619	109,818
Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Real Estate Loans [Member] | Commercial construction [Member]
Nonaccrual loans
Loans		7,115,803	3,190,193
Nonaccrual interest not accrued
Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due			113,603
Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Commercial Portfolio Segment [Member]
Nonaccrual loans		165,285
Loans	[1]	40,143,965	21,537,366
Nonaccrual interest not accrued		12,891
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		135,502
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		134,524
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Home equity loans [Member]
Nonaccrual loans		12,605	3,397
Loans		19,995,789	20,544,370
Nonaccrual interest not accrued		436	66
Home equity loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Home equity loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Home equity loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Consumer Portfolio Segment [Member]
Nonaccrual loans		4,850	5,602
Loans	[2]	19,615,511	3,196,436
Nonaccrual interest not accrued		385	317
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		148,876
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		28,300
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Legacy Loans [Member]
Current		270,807,643	207,328,184
Past due		1,315,929	578,823
Nonaccrual loans		5,126,537	1,990,539
Loans	[3]	277,250,109	209,897,546
Nonaccrual interest not accrued		325,094	123,326
Legacy Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		347,996	504,192
Legacy Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		233,115	74,631
Legacy Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		734,818
Legacy Loans [Member] | Real Estate Loans [Member]
Loans	[3]	206,141,595	174,842,452
Legacy Loans [Member] | Real Estate Loans [Member] | Residential [Member]
Nonaccrual loans		526,584	426,354
Loans		90,699,011	73,552,753
Nonaccrual interest not accrued		8,250	6,460
Legacy Loans [Member] | Real Estate Loans [Member] | Residential [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		63,618	69,618
Legacy Loans [Member] | Real Estate Loans [Member] | Residential [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		70,291	74,631
Legacy Loans [Member] | Real Estate Loans [Member] | Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Legacy Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member]
Nonaccrual loans		60,949	13,976
Loans		9,275,031	6,742,469
Nonaccrual interest not accrued		8,513	6,982
Legacy Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due			320,971
Legacy Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Legacy Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		734,818
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial [Member]
Nonaccrual loans		4,356,264	1,546,812
Loans	[3]	100,403,769	92,665,689
Nonaccrual interest not accrued		294,619	109,818
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member]
Nonaccrual loans
Loans	[3]	5,763,784	1,881,541
Nonaccrual interest not accrued
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due			113,603
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Legacy Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Legacy Loans [Member] | Commercial Portfolio Segment [Member]
Nonaccrual loans		165,285
Loans	[1],[3]	38,302,739	19,518,029
Nonaccrual interest not accrued		12,891
Legacy Loans [Member] | Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		135,502
Legacy Loans [Member] | Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		134,524
Legacy Loans [Member] | Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Legacy Loans [Member] | Home equity loans [Member]
Nonaccrual loans		12,605	3,397
Loans	[3]	13,956,327	13,278,229
Nonaccrual interest not accrued		436	66
Legacy Loans [Member] | Home equity loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Legacy Loans [Member] | Home equity loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Legacy Loans [Member] | Home equity loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Legacy Loans [Member] | Consumer Portfolio Segment [Member]
Nonaccrual loans		4,850
Loans	[2],[3]	18,849,448	2,258,836
Nonaccrual interest not accrued		385
Legacy Loans [Member] | Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		148,876
Legacy Loans [Member] | Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due		28,300
Legacy Loans [Member] | Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Acquired Loans [Member]
Current		109,972,473	128,769,860
Past due		1,160,787	21,030
Nonaccrual loans		837,870	311,396
Loans		111,971,130	129,102,286
Nonaccrual interest not accrued		68,724	58,787
Acquired Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		689,364
Acquired Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		471,423	21,030
Acquired Loans [Member] | Real Estate Loans [Member]
Loans		103,324,379	118,879,208
Acquired Loans [Member] | Real Estate Loans [Member] | Residential [Member]
Nonaccrual loans		338,060	248,663
Loans		72,749,066	83,892,389
Nonaccrual interest not accrued		53,120	35,177
Acquired Loans [Member] | Real Estate Loans [Member] | Residential [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due		689,364
Acquired Loans [Member] | Real Estate Loans [Member] | Residential [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member]
Nonaccrual loans		300,872	57,131
Loans		17,460,809	18,779,644
Nonaccrual interest not accrued		15,604	23,293
Acquired Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Investor Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due		471,423	21,030
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial [Member]
Nonaccrual loans		198,938
Loans		11,762,485	14,898,523
Nonaccrual interest not accrued
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member]
Nonaccrual loans
Loans		1,352,019	1,308,652
Nonaccrual interest not accrued
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Real Estate Loans [Member] | Commercial construction [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Acquired Loans [Member] | Commercial Portfolio Segment [Member]
Nonaccrual loans
Loans	[1]	1,841,226	2,019,337
Nonaccrual interest not accrued
Acquired Loans [Member] | Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Acquired Loans [Member] | Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Acquired Loans [Member] | Home equity loans [Member]
Nonaccrual loans
Loans		6,039,462	7,266,141
Nonaccrual interest not accrued
Acquired Loans [Member] | Home equity loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Acquired Loans [Member] | Home equity loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Home equity loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due
Acquired Loans [Member] | Consumer Portfolio Segment [Member]
Nonaccrual loans			5,602
Loans	[2]	766,063	937,600
Nonaccrual interest not accrued			317
Acquired Loans [Member] | Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Acquired Loans [Member] | Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Acquired Loans [Member] | Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due

[1] "Legacy" commercial business loans at March 31, 2018 includes a $15.5 million pool of commercial lease loans purchased in June 2017 and $3.2 million in guaranteed SBA purchased loans.

[2] "Legacy" consumer loans at March 31, 2018 includes $19.9 million of purchased loan pools consisting of recreational vehicles that were purchased in August and December 2017.

[3] As a result of the acquisition of Fraternity Community Bancorp, Inc., the parent company of Fraternity Federal Savings and Loan, in May 2016 and Fairmount Bancorp, Inc., the parent company of Fairmount Bank, in September 2015, we have segmented the portfolio into two components, loans originated by Hamilton Bank "Legacy" and loans acquired from Fraternity Community Bancorp, Inc. and Fairmount Bancorp, Inc. "Acquired".