Accumulated other comprehensive loss 1 of 2 (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustment – net of tax	$ (8,647)	$ (30,364)
Pension liability – net of tax	(49,889)	(61,936)
Postretirement obligations – net of tax	1,372	888
Split-dollar life insurance arrangements – net of tax	(1,462)	(1,668)
Derivatives qualifying as hedges – net of tax	(1,515)	(5,078)
Net unrealized investment gain – net of tax	883	694
Accumulated other comprehensive loss	$ (59,258)	$ (97,464)