Note 12 - Accumulated Other Comprehensive (Loss) - AOCI Reclass (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Other income (expense), net	$ 201		$ 201
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Other-than-Temporary Impairment Attributable to Parent [Member]
Other income (expense), net		(454)	(151)	(454)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Income before Income Tax Provision	201	(454)	50	(454)
Tax impact	(80)	182	(19)	182
Total reclassifications for the period	121	(272)	31	(272)
Other income (expense), net	586	(1,010)	1,401	(1,800)
Income before Income Tax Provision	6,795	5,778	12,066	10,425
Tax impact	(2,860)	(2,505)	(5,112)	(4,167)
Total reclassifications for the period	$ 3,935	$ 3,273	$ 6,954	$ 6,258