Consolidated Statement of Stockholders Equity - USD ($) $ in Thousands	Total	Directors	Common Stock ($0.01 par value)	Additional Paid-in Capital	Additional Paid-in Capital Directors	Retained Earnings	Accumulated Other Comprehensive Loss
Opening Balance at Mar. 31, 2017	$ 341,350		$ 226	$ 258,853		$ 179,735	$ (97,464)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,065		0	0		22,065	0
Payments of Dividends	(3,903)		0	0		3,903	0
Change in foreign currency translation adjustment	21,717		0	0		0	21,717
Change in net unrealized gain on investments, net of tax	189		0	0		0	189
Change in derivatives qualifying as hedges, net of tax	3,563		0	0		0	3,563
Change in pension liability and postretirement obligations, net of tax	12,737		0	0		0	12,737
Stock compensation - directors	5,156	$ 430	0	5,156	$ 430	0	0
Stock Issued During Period, Value, Stock Options Exercised	6,332		4	6,328		0	0
Restricted stock units released, shares, net of shares withheld for minimum statutory tax obligation	(1,407)		0	(1,407)		0	0
closing balance at Mar. 31, 2018	408,229		230	269,360		197,897	(59,258)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	42,577		0	0		42,577	0
Payments of Dividends	(4,903)		0	0		4,903	0
Change in foreign currency translation adjustment	(16,708)		0	0		0	(16,708)
Change in net unrealized gain on investments, net of tax	(883)		0	0		0	(883)
Change in derivatives qualifying as hedges, net of tax	(1,037)		0	0		0	(1,037)
Change in pension liability and postretirement obligations, net of tax	(5,166)		0	0		0	(5,166)
Stock compensation - directors	5,768	430	0	5,768	430	0	0
Stock Issued During Period, Value, Stock Options Exercised	4,152		4	4,148		0	0
Tax effect of exercise of stock options	(2,188)			2,188			0
closing balance at Mar. 31, 2019	431,159		234	277,518		236,459	(83,052)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets | Accounting Standards Update 2016-01 [Member]	888		0	0		888	0
Net income	59,672		0	0		59,672	0
Payments of Dividends	(5,690)
Dividends declared			0	0		(5,690)	0
Change in foreign currency translation adjustment	(9,004)		0	0		0	(9,004)
Change in derivatives qualifying as hedges, net of tax	1,602		0	0		0	1,602
Change in pension liability and postretirement obligations, net of tax	(23,896)		0	0		0	(23,896)
Stock compensation - directors	4,047	$ 460	0	4,047	$ 460	0	0
Stock Issued During Period, Value, Stock Options Exercised	6,000		3	5,997		0	0
Tax effect of exercise of stock options							0
Restricted stock units released, shares, net of shares withheld for minimum statutory tax obligation	(765)		1	(766)		0
closing balance at Mar. 31, 2020	$ 463,585		$ 238	$ 287,256		$ 290,441	$ (114,350)