Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Revenues and long-lived assets by geographic region
Number of reportable segments	1	2
United States
Revenues and long-lived assets by geographic region
Operating Revenues	$ 1,806,990	$ 1,919,680	$ 1,866,909
Intangible Assets and Goodwill	3,548,628	3,565,019	3,590,283
United Kingdom
Revenues and long-lived assets by geographic region
Operating Revenues	448,863	512,313	478,510
Intangible Assets and Goodwill	1,108,297	1,136,386	1,139,065
Other International
Revenues and long-lived assets by geographic region
Operating Revenues	406,721	352,324	289,460
Intangible Assets and Goodwill	474,986	487,022	488,170
All Countries
Revenues and long-lived assets by geographic region
Operating Revenues	2,662,574	2,784,317	2,634,879
Intangible Assets and Goodwill	$ 5,131,911	$ 5,188,427	$ 5,217,518