Schedule of Goodwill Carrying Value Rollfoward (Details 4) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Goodwill Gross Value [Member]
Goodwill
Goodwill, Gross		$ 3,086,789	$ 2,641,416	$ 2,501,410
Impact of excess tax basis amortization		(20,818)	(20,920)
Goodwill, Acquired During Period	[1]	491,835	163,110
Other, including changes in foreign exchange rates		(25,644)	(2,184)
Goodwill Accumulated Impairment [Member]
Goodwill
Goodwill, Impaired, Accumulated Impairment Loss		(1,161,900)	(1,161,900)	(1,161,900)
Impact of excess tax basis amortization		0	0
Goodwill, Acquired During Period		0	0
Other, including changes in foreign exchange rates		0	0
Goodwill Net Value [Member]
Goodwill
Goodwill		1,924,889	1,479,516	$ 1,339,510
Impact of excess tax basis amortization		(20,818)	(20,920)
Goodwill, Acquired During Period	[1]	491,835	163,110
Other, including changes in foreign exchange rates		$ (25,644)	$ (2,184)

[1] See Note 2 for additional information.