Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions	Total	Ordinary Shares	Additional Paid-in Capital	Treasury Shares	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total Equity of MKHL	Non-controlling Interests
Beginning balance at Apr. 01, 2017					$ (80.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 125.5
Other comprehensive loss					12.4
Comprehensive income	137.9
Ending balance at Jul. 01, 2017					(68.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of an accounting standards (See Note 2)	11.7					$ 11.7	$ 11.7
Balance as of April 1, 2018	$ 2,033.2		$ 831.1	$ (3,015.9)	50.5	4,163.7	2,029.4	$ 3.8
Beginning balance (in shares) at Mar. 31, 2018	210,991,091	210,991,000
Beginning balance (in shares) at Mar. 31, 2018	(61,292,684)			(61,293,000)
Beginning balance at Mar. 31, 2018	$ 2,021.5	$ 0.0	831.1	$ (3,015.9)	50.5	4,152.0	2,017.7	3.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	186.2					186.4	186.4	(0.2)
Other comprehensive loss	(91.0)				(91.0)		(91.0)	0.0
Comprehensive income	95.2						95.4	(0.2)
Vesting of restricted awards, net of forfeitures (in shares)		600,000
Exercises of employee share options (in shares)		619,000
Exercise of employee share options	6.2		6.2				6.2
Equity compensation expense	12.8		12.8				12.8
Purchase of treasury shares (in shares)				(1,748,000)
Purchase of treasury shares	$ (105.9)			$ (105.9)			(105.9)
Ending balance (in shares) at Jun. 30, 2018	212,209,545	212,210,000
Ending balance (in shares) at Jun. 30, 2018	(63,040,950)			(63,041,000)
Ending balance at Jun. 30, 2018	$ 2,041.5	$ 0.0	$ 850.1	$ (3,121.8)	$ (40.5)	$ 4,350.1	$ 2,037.9	$ 3.6