Note 4 - 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, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Beginning balance			$ 16,062
Ending balance	$ 17,813		17,813
Allowances for Doubtful Accounts [Member]
Beginning balance	1,670	$ 1,327	1,276	$ 1,893
Charges	355	0	927	81
Applications	(83)	(153)	(253)	(800)
Translation, acquisition and other	4	14	(4)	14
Ending balance	1,946	1,188	1,946	1,188
Allowance for Stock Rotation and Ship from Stock and Debit [Member]
Beginning balance	14,756	10,201	14,140	15,989
Charges	6,169	6,658	16,757	20,122
Applications	(5,427)	(6,338)	(15,399)	(19,264)
Stock rotation reclassified to liability	0	0	0	(6,326)
Ending balance	15,498	10,521	15,498	10,521
Allowance and Reserve for Sales Returns and Discounts [Member]
Beginning balance	947	338	646	6,875
Charges	1,336	173	4,830	2,233
Applications	(1,914)	(114)	(5,107)	(2,548)
Translation, acquisition and other	0	0	0	(6)
Stock rotation reclassified to liability	0	0	0	(6,157)
Ending balance	$ 369	$ 397	$ 369	$ 397