Note 15 - Quarterly Financial Information (Unaudited) (Details) - Quarterly Financial Information (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
2014
Operating Revenues	$ 100,772,045	$ 103,064,239
Operating Income	2,632,540	2,728,028
Net Income	1,466,636	1,669,860
Basic Earnings per share (in Dollars per share)	$ 0.61	$ 0.68
Diluted Earnings per share (in Dollars per share)	$ 0.60	$ 0.68
First Quarter [Member]
2014
Operating Revenues	21,280,000	24,488,000
Operating Income	221,000	654,000
Net Income	139,000	417,000
Basic Earnings per share (in Dollars per share)	$ 0.06	$ 0.17
Diluted Earnings per share (in Dollars per share)	$ 0.06	$ 0.17
Second Quarter [Member]
2014
Operating Revenues	24,190,000	21,162,000
Operating Income	752,000	351,000
Net Income	456,000	227,000
Basic Earnings per share (in Dollars per share)	$ 0.19	$ 0.09
Diluted Earnings per share (in Dollars per share)	$ 0.18	$ 0.09
Third Quarter [Member]
2014
Operating Revenues	29,835,000	26,703,000
Operating Income	796,000	986,000
Net Income	455,000	633,000
Basic Earnings per share (in Dollars per share)	$ 0.19	$ 0.26
Diluted Earnings per share (in Dollars per share)	$ 0.19	$ 0.26
Fourth Quarter [Member]
2014
Operating Revenues	25,467,000	30,711,000
Operating Income	864,000	737,000
Net Income	$ 417,000	$ 393,000
Basic Earnings per share (in Dollars per share)	$ 0.17	$ 0.16
Diluted Earnings per share (in Dollars per share)	$ 0.17	$ 0.16