Note 3 - Comprehensive Income - Components of Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Foreign currency translation adjustment, pre-tax	$ 76,711	$ (14,674)	$ 14,330
Foreign currency translation adjustment, net of tax	76,711	(14,674)	14,330
Foreign currency cash flow hedges adjustment, pre-tax	(626)	205	29
Foreign currency cash flow hedges adjustment, net of tax	(490)	183	2
Pension liability adjustment, pre-tax	16,063	(10,155)	11,077
Pension liability adjustment, net of tax	12,199	(7,527)	8,209
Other post-employment obligations, pre-tax		(777)	(244)
Other post-employment obligations		(777)	(244)
Other comprehensive income (loss), pre-tax	92,148	(25,401)	25,192
Other comprehensive income (loss), net of tax	$ 88,420	$ (22,795)	$ 22,297