Note 5 - Trade Accounts Receivable and Contract Liabilities - Charges Related to Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Beginning balance			$ 24,757
Ending balance	$ 12,106		12,106
Allowances for Doubtful Accounts [Member]
Beginning balance	1,327	$ 601	1,893	$ 1,285
Charges			81	164
Applications	(153)	(143)	(800)	(991)
Translation, acquisition and other	14	723	14	723
Ending balance	1,188	1,181	1,188	1,181
Allowance for Stock Rotation and Ship from Stock and Debit [Member]
Beginning balance	10,201	15,119	15,989	14,853
Charges	6,658	8,309	20,122	22,575
Applications	(6,338)	(7,901)	(19,264)	(21,901)
Stock rotation reclassified to liability			(6,326)
Ending balance	10,521	15,527	10,521	15,527
Allowance and Reserve for Sales Returns and Discounts [Member]
Beginning balance	338	5,076	6,875	5,623
Charges	173	6,105	2,233	12,885
Applications	(114)	(4,877)	(2,548)	(12,249)
Translation, acquisition and other		93	(6)	138
Stock rotation reclassified to liability			(6,157)
Ending balance	$ 397	$ 6,397	$ 397	$ 6,397