Note 5 - Loans Receivable and Allowance for Loan Losses - Loans by Risk Grade (Details) - USD ($)		Sep. 30, 2018		Mar. 31, 2018		Sep. 30, 2017
Loans		$ 374,648,865		$ 389,221,239
Financial Asset Originated [Member]
Loans		270,108,968	[1]	277,250,109	[1]	$ 249,358,443
Financial Asset Acquired [Member]
Loans		104,539,897		111,971,130		118,290,856
Pass [Member]
Loans		364,310,032		375,484,442
Pass [Member] | Financial Asset Originated [Member]
Loans		262,882,443		266,444,555
Pass [Member] | Financial Asset Acquired [Member]
Loans		101,427,589		109,039,887
Special Mention [Member]
Loans		3,718,787		7,022,190
Special Mention [Member] | Financial Asset Originated [Member]
Loans		2,335,187		5,688,785
Special Mention [Member] | Financial Asset Acquired [Member]
Loans		1,383,600		1,333,405
Substandard [Member]
Loans		6,620,046		6,714,607
Substandard [Member] | Financial Asset Originated [Member]
Loans		4,891,338		5,116,769
Substandard [Member] | Financial Asset Acquired [Member]
Loans		1,728,708		1,597,838
Doubtful [Member]
Loans
Doubtful [Member] | Financial Asset Originated [Member]
Loans
Doubtful [Member] | Financial Asset Acquired [Member]
Loans
Unlikely to be Collected Financing Receivable [Member]
Loans
Unlikely to be Collected Financing Receivable [Member] | Financial Asset Originated [Member]
Loans
Unlikely to be Collected Financing Receivable [Member] | Financial Asset Acquired [Member]
Loans
Real Estate Loans [Member]
Loans		299,698,738		309,465,974
Real Estate Loans [Member] | Financial Asset Originated [Member]
Loans	[1]	202,817,744		206,141,595
Real Estate Loans [Member] | Financial Asset Acquired [Member]
Loans		96,880,994		103,324,379
Real Estate Loans [Member] | Residential [Member] | Financial Asset Originated [Member]
Loans		86,729,410				74,806,476
Real Estate Loans [Member] | Residential [Member] | Financial Asset Acquired [Member]
Loans		68,932,853				77,663,426
Real Estate Loans [Member] | Residential [Member] | Pass [Member]
Loans		150,963,245		158,765,098
Real Estate Loans [Member] | Residential [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		83,998,596		87,863,805
Real Estate Loans [Member] | Residential [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		66,964,649		70,901,293
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member]
Loans		3,290,501		3,291,173
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans		2,324,604		2,365,652
Real Estate Loans [Member] | Residential [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans		965,897		925,521
Real Estate Loans [Member] | Residential [Member] | Substandard [Member]
Loans		1,408,517		1,391,806
Real Estate Loans [Member] | Residential [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans		406,210		469,554
Real Estate Loans [Member] | Residential [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans		1,002,307		922,252
Real Estate Loans [Member] | Investor Loans [Member] | Financial Asset Originated [Member]
Loans		7,880,161				9,627,329
Real Estate Loans [Member] | Investor Loans [Member] | Financial Asset Acquired [Member]
Loans		17,002,667				18,423,892
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member]
Loans		24,045,185		25,933,428
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		7,820,735		9,214,082
Real Estate Loans [Member] | Investor Loans [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		16,224,450		16,719,346
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member]
Loans		279,685		297,209
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans
Real Estate Loans [Member] | Investor Loans [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans		279,685		297,209
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member]
Loans		557,959		505,203
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans		59,426		60,949
Real Estate Loans [Member] | Investor Loans [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans		498,533		444,254
Real Estate Loans [Member] | Commercial [Member]
Loans		115,696,478		112,166,254
Real Estate Loans [Member] | Commercial [Member] | Financial Asset Originated [Member]
Loans		105,679,013	[1]	100,403,769	[1]	94,957,970
Real Estate Loans [Member] | Commercial [Member] | Financial Asset Acquired [Member]
Loans		10,017,465		11,762,485		12,114,557
Real Estate Loans [Member] | Commercial [Member] | Pass [Member]
Loans		111,248,572		104,518,917
Real Estate Loans [Member] | Commercial [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		101,427,804		92,955,370
Real Estate Loans [Member] | Commercial [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		9,820,768		11,563,547
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member]
Loans				3,092,135
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans				3,092,135
Real Estate Loans [Member] | Commercial [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member]
Loans		4,447,906		4,555,202
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans		4,251,209		4,356,264
Real Estate Loans [Member] | Commercial [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans		196,697		198,938
Real Estate Loans [Member] | Commercial Construction [Member]
Loans		3,457,168		7,115,803
Real Estate Loans [Member] | Commercial Construction [Member] | Financial Asset Originated [Member]
Loans		2,529,160	[1]	5,763,784	[1]	2,081,647
Real Estate Loans [Member] | Commercial Construction [Member] | Financial Asset Acquired [Member]
Loans		928,008		1,352,019		1,058,534
Real Estate Loans [Member] | Commercial Construction [Member] | Pass [Member]
Loans		3,457,168		7,115,803
Real Estate Loans [Member] | Commercial Construction [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		2,529,160		5,763,784
Real Estate Loans [Member] | Commercial Construction [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		928,008		1,352,019
Real Estate Loans [Member] | Commercial Construction [Member] | Special Mention [Member]
Loans
Real Estate Loans [Member] | Commercial Construction [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans
Real Estate Loans [Member] | Commercial Construction [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans
Real Estate Loans [Member] | Commercial Construction [Member] | Substandard [Member]
Loans
Real Estate Loans [Member] | Commercial Construction [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans
Real Estate Loans [Member] | Commercial Construction [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans
Commercial Portfolio Segment [Member]
Loans	[2]	37,889,576		40,143,965
Commercial Portfolio Segment [Member] | Financial Asset Originated [Member]
Loans		36,134,376	[1],[2]	38,302,739	[1],[2]	34,042,543
Commercial Portfolio Segment [Member] | Financial Asset Acquired [Member]
Loans		1,755,200	[2]	1,841,226	[2]	1,668,783
Commercial Portfolio Segment [Member] | Pass [Member]
Loans		37,722,337		39,819,519
Commercial Portfolio Segment [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		35,967,137		37,978,293
Commercial Portfolio Segment [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		1,755,200		1,841,226
Commercial Portfolio Segment [Member] | Special Mention [Member]
Loans				134,524
Commercial Portfolio Segment [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans				134,524
Commercial Portfolio Segment [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans
Commercial Portfolio Segment [Member] | Substandard [Member]
Loans		167,239		189,922
Commercial Portfolio Segment [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans		167,239		189,922
Commercial Portfolio Segment [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans
Home Equity Loans [Member]
Loans		19,367,708		19,995,789
Home Equity Loans [Member] | Financial Asset Originated [Member]
Loans		14,183,532	[1]	13,956,327	[1]	13,664,414
Home Equity Loans [Member] | Financial Asset Acquired [Member]
Loans		5,184,176		6,039,462		6,459,424
Home Equity Loans [Member] | Pass [Member]
Loans		19,222,436		19,864,519
Home Equity Loans [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		14,176,278		13,935,732
Home Equity Loans [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		5,046,158		5,928,787
Home Equity Loans [Member] | Special Mention [Member]
Loans		138,018		110,675
Home Equity Loans [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans
Home Equity Loans [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans		138,018		110,675
Home Equity Loans [Member] | Substandard [Member]
Loans		7,254		20,595
Home Equity Loans [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans		7,254		20,595
Home Equity Loans [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans
Consumer Portfolio Segment [Member]
Loans	[3]	17,692,843		19,615,511
Consumer Portfolio Segment [Member] | Financial Asset Originated [Member]
Loans		16,973,316	[1],[3]	18,849,448	[1],[3]	20,178,064
Consumer Portfolio Segment [Member] | Financial Asset Acquired [Member]
Loans		719,528		766,063	[3]	$ 902,240
Consumer Portfolio Segment [Member] | Pass [Member]
Loans		17,651,089		19,467,158
Consumer Portfolio Segment [Member] | Pass [Member] | Financial Asset Originated [Member]
Loans		16,962,733		18,733,489
Consumer Portfolio Segment [Member] | Pass [Member] | Financial Asset Acquired [Member]
Loans		688,356		733,669
Consumer Portfolio Segment [Member] | Special Mention [Member]
Loans		10,583		96,474
Consumer Portfolio Segment [Member] | Special Mention [Member] | Financial Asset Originated [Member]
Loans		10,583		96,474
Consumer Portfolio Segment [Member] | Special Mention [Member] | Financial Asset Acquired [Member]
Loans
Consumer Portfolio Segment [Member] | Substandard [Member]
Loans		31,171		51,879
Consumer Portfolio Segment [Member] | Substandard [Member] | Financial Asset Originated [Member]
Loans				19,485
Consumer Portfolio Segment [Member] | Substandard [Member] | Financial Asset Acquired [Member]
Loans		$ 31,171		$ 32,394

[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 March 31, 2018 includes a $15.5 million pool of commercial lease loans purchased in June 2017 and $3.2 million in guaranteed SBA loans purchased in second half of fiscal 2018.

[3] "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.