Note 6 - Loans Receivable and Allowance for Loan Losses - Loans by Risk Grade (Details) - USD ($)		Sep. 30, 2017		Mar. 31, 2017		Sep. 30, 2016
Loans		$ 367,649,299		$ 338,999,832
Legacy Loans [Member]
Loans		249,358,443	[1]	209,897,546	[1]	$ 184,732,846
Acquired Loans [Member]
Loans		118,290,856		129,102,286		144,920,670
Pass [Member]
Loans		352,813,344		324,151,352
Pass [Member] | Legacy Loans [Member]
Loans		238,586,097		200,026,200
Pass [Member] | Acquired Loans [Member]
Loans		114,227,247		124,125,152
Special Mention [Member]
Loans		8,206,658		11,401,812
Special Mention [Member] | Legacy Loans [Member]
Loans		5,658,349		7,828,565
Special Mention [Member] | Acquired Loans [Member]
Loans		2,548,309		3,573,247
Substandard [Member]
Loans		6,629,297		3,446,668
Substandard [Member] | Legacy Loans [Member]
Loans		5,113,997		2,042,781
Substandard [Member] | Acquired Loans [Member]
Loans		1,515,300		1,403,887
Doubtful [Member]
Loans
Doubtful [Member] | Legacy Loans [Member]
Loans
Doubtful [Member] | Acquired Loans [Member]
Loans
Unlikely to be Collected Financing Receivable [Member]
Loans
Unlikely to be Collected Financing Receivable [Member] | Legacy Loans [Member]
Loans
Unlikely to be Collected Financing Receivable [Member] | Acquired Loans [Member]
Loans
Real Estate Loans [Member]
Loans		290,733,831		293,721,660
Real Estate Loans [Member] | Legacy Loans [Member]
Loans	[1]	181,473,422		174,842,452
Real Estate Loans [Member] | Acquired Loans [Member]
Loans		109,260,409		118,879,208
Real Estate Loans [Member] | Residential [Member] | Legacy Loans [Member]
Loans		74,806,476				49,425,637
Real Estate Loans [Member] | Residential [Member] | Acquired Loans [Member]
Loans		77,663,426				91,528,556
Real Estate Loans [Member] | Residential [Member] | Pass [Member]
Loans		147,348,299		152,949,798
Real Estate Loans [Member] | Residential [Member] | Pass [Member] | Legacy Loans [Member]
Loans		71,978,910		71,721,341
Real Estate Loans [Member] | Residential [Member] | Pass [Member] | Acquired Loans [Member]
Loans		75,369,389		81,228,457
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member]
Loans		3,763,156		3,224,423
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans		2,537,371		1,499,436
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans		1,225,785		1,724,987
Real Estate Loans [Member] | Residential [Member] | Substandard [Member]
Loans		1,358,447		1,270,921
Real Estate Loans [Member] | Residential [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		290,195		331,976
Real Estate Loans [Member] | Residential [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		1,068,252		938,945
Real Estate Loans [Member] | Investor Loans [Member] | Legacy Loans [Member]
Loans		9,627,329				10,919,294
Real Estate Loans [Member] | Investor Loans [Member] | Acquired Loans [Member]
Loans		18,423,892				22,076,549
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member]
Loans		28,051,221		24,880,026
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member] | Legacy Loans [Member]
Loans		9,627,329		6,728,493
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member] | Acquired Loans [Member]
Loans		18,423,892		18,151,533
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member]
Loans				408,803
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans				408,803
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member]
Loans				233,284
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member] | Legacy Loans [Member]
Loans				13,976
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member] | Acquired Loans [Member]
Loans				219,308
Real Estate Loans [Member] | Commercial [Member]
Loans		107,072,527		107,564,212
Real Estate Loans [Member] | Commercial [Member] | Legacy Loans [Member]
Loans		94,957,970	[1],[2]	92,665,689	[1]	91,086,852
Real Estate Loans [Member] | Commercial [Member] | Acquired Loans [Member]
Loans		12,114,557		14,898,523		17,379,910
Real Estate Loans [Member] | Commercial [Member] | Pass [Member]
Loans		97,625,564		98,177,735
Real Estate Loans [Member] | Commercial [Member] | Pass [Member] | Legacy Loans [Member]
Loans		87,129,337		84,789,748
Real Estate Loans [Member] | Commercial [Member] | Pass [Member] | Acquired Loans [Member]
Loans		10,496,227		13,387,987
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member]
Loans		4,326,747		7,634,821
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans		3,120,978		6,329,129
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans		1,205,769		1,305,692
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member]
Loans		5,120,216		1,751,656
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		4,707,655		1,546,812
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		412,561		204,844
Real Estate Loans [Member] | Commercial construction [Member]
Loans		3,140,181		3,190,193
Real Estate Loans [Member] | Commercial construction [Member] | Legacy Loans [Member]
Loans		2,081,647	[1]	1,881,541	[1]	999,407
Real Estate Loans [Member] | Commercial construction [Member] | Acquired Loans [Member]
Loans		1,058,534		1,308,652		1,797,272
Real Estate Loans [Member] | Commercial construction [Member] | Pass [Member]
Loans		3,140,181		3,190,193
Real Estate Loans [Member] | Commercial construction [Member] | Pass [Member] | Legacy Loans [Member]
Loans		2,081,647		1,881,541
Real Estate Loans [Member] | Commercial construction [Member] | Pass [Member] | Acquired Loans [Member]
Loans		1,058,534		1,308,652
Real Estate Loans [Member] | Commercial construction [Member] | Special Mention [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Substandard [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Substandard [Member] | Legacy Loans [Member]
Loans
Real Estate Loans [Member] | Commercial construction [Member] | Substandard [Member] | Acquired Loans [Member]
Loans
Commercial Portfolio Segment [Member]
Loans		35,711,326		21,537,366
Commercial Portfolio Segment [Member] | Legacy Loans [Member]
Loans		34,042,543	[1]	19,518,029	[1]	16,210,542
Commercial Portfolio Segment [Member] | Acquired Loans [Member]
Loans		1,668,783		2,019,337		2,133,711
Commercial Portfolio Segment [Member] | Pass [Member]
Loans		35,617,743		21,396,100
Commercial Portfolio Segment [Member] | Pass [Member] | Legacy Loans [Member]
Loans		33,948,960		19,376,763
Commercial Portfolio Segment [Member] | Pass [Member] | Acquired Loans [Member]
Loans		1,668,783		2,019,337
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans
Commercial Portfolio Segment [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Commercial Portfolio Segment [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans		93,583		141,266
Commercial Portfolio Segment [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		93,583		141,266
Commercial Portfolio Segment [Member] | Substandard [Member] | Acquired Loans [Member]
Loans
Home equity loans [Member]
Loans		20,123,838		20,544,370
Home equity loans [Member] | Legacy Loans [Member]
Loans		13,664,414	[1]	13,278,229	[1]	13,427,376
Home equity loans [Member] | Acquired Loans [Member]
Loans		6,459,424		7,266,141		8,996,210
Home equity loans [Member] | Pass [Member]
Loans		19,984,519		20,402,642
Home equity loans [Member] | Pass [Member] | Legacy Loans [Member]
Loans		13,641,850		13,269,478
Home equity loans [Member] | Pass [Member] | Acquired Loans [Member]
Loans		6,342,669		7,133,164
Home equity loans [Member] | Special Mention [Member]
Loans		116,755		132,977
Home equity loans [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Home equity loans [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans		116,755		132,977
Home equity loans [Member] | Substandard [Member]
Loans		22,564		8,751
Home equity loans [Member] | Substandard [Member] | Legacy Loans [Member]
Loans		22,564		8,751
Home equity loans [Member] | Substandard [Member] | Acquired Loans [Member]
Loans
Consumer Portfolio Segment [Member]
Loans	[3]	21,080,304		3,196,436
Consumer Portfolio Segment [Member] | Legacy Loans [Member]
Loans		20,178,064	[1],[3]	2,258,836	[1],[3]	2,663,738
Consumer Portfolio Segment [Member] | Acquired Loans [Member]
Loans		902,240	[3]	937,600	[3]	$ 1,008,462
Consumer Portfolio Segment [Member] | Pass [Member]
Loans		21,045,817		3,154,858
Consumer Portfolio Segment [Member] | Pass [Member] | Legacy Loans [Member]
Loans		20,178,064		2,258,836
Consumer Portfolio Segment [Member] | Pass [Member] | Acquired Loans [Member]
Loans		867,753		896,022
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans				788
Consumer Portfolio Segment [Member] | Special Mention [Member] | Legacy Loans [Member]
Loans
Consumer Portfolio Segment [Member] | Special Mention [Member] | Acquired Loans [Member]
Loans				788
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans		34,487		40,790
Consumer Portfolio Segment [Member] | Substandard [Member] | Legacy Loans [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member] | Acquired Loans [Member]
Loans		$ 34,487		$ 40,790

[1] 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".

[2] "Legacy" commercial business loans at June 30, 2017 includes $15.4 million of loans purchased in June 2017.

[3] "Legacy" consumer loans as of September 30, 2017 includes $18.4 million of recreational vehicle loans purchased in August 2017.