Restructuring Costs Restructuring costs (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Restructuring Costs [Line Items]
Restructuring and impairment costs	[1]	$ 0	$ 178	$ 0	$ 3,860

[1] Restructuring and impairment costs are excluded from segment operating income, but are included in consolidated operating income in the consolidated statements of income and comprehensive income.