Note 11 - Pension Plans - Information on Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Mar. 31, 2016
Defined Benefit Plan, Fair Value of Plan Assets	$ 27,319	$ 28,714
Cash and Cash Equivalents [Member]
Defined Benefit Plan, Fair Value of Plan Assets	103	121
Equity Securities [Member]
Defined Benefit Plan, Fair Value of Plan Assets	305	351
Fixed Income Funds [Member]
Defined Benefit Plan, Fair Value of Plan Assets	1,269	1,321
Mutual Fund [Member]
Defined Benefit Plan, Fair Value of Plan Assets	25,642	26,921
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	14,510	15,224
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Fair Value of Plan Assets	103	121
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan, Fair Value of Plan Assets	305	351
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan, Fair Value of Plan Assets	1,211	1,225
Fair Value, Inputs, Level 1 [Member] | Mutual Fund [Member]
Defined Benefit Plan, Fair Value of Plan Assets	12,891	13,527
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Fair Value of Plan Assets	12,809	13,490
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan, Fair Value of Plan Assets
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan, Fair Value of Plan Assets	58	96
Fair Value, Inputs, Level 2 [Member] | Mutual Fund [Member]
Defined Benefit Plan, Fair Value of Plan Assets	$ 12,751	$ 13,394