Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss)
Beginning of the period			$ 856,111	$ 759,948
Other comprehensive income (loss)	$ 3,636	$ (4,317)	5,539	(447)
End of the period	1,007,236	801,395	1,007,236	801,395
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss)
Beginning of the period			(89,708)
Other comprehensive income (loss)			5,176
End of the period	(84,532)		(84,532)
Defined Benefit Plan
Accumulated Other Comprehensive Income (Loss)
Beginning of the period			(10,480)
Other comprehensive income (loss)			1,012
End of the period	(9,468)		(9,468)
Deferred Hedging Losses
Accumulated Other Comprehensive Income (Loss)
Beginning of the period			(518)
Other comprehensive income (loss)			(649)
End of the period	(1,167)		(1,167)
Total
Accumulated Other Comprehensive Income (Loss)
Beginning of the period			(100,706)	(111,985)
Other comprehensive income (loss)			5,539
End of the period	$ (95,167)	$ (112,432)	$ (95,167)	$ (112,432)