GOODWILL (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Sep. 30, 2011 Component Y Multiple Segment	Mar. 31, 2011
Asset Impairment Charges
Impairment charge related to goodwill		$ 77,300
Goodwill
Goodwill at the beginning of the period	417,654
Purchase adjustments	1
Change in foreign currency translation adjustment	(3,993)
Goodwill at the end of the period	413,662	417,654
Goodwill Impairment Testing
Goodwill included in each component tested	413,662	417,654
Number of reportable segments	2
Number of components tested for impairment	7
Information services
Goodwill
Goodwill at the beginning of the period	347,411
Purchase adjustments	1
Change in foreign currency translation adjustment	(3,048)
Goodwill at the end of the period	344,364
Passing margin component (as a percent)	20.00%
Goodwill Impairment Testing
Goodwill included in each component tested	344,364
US Information Services
Goodwill
Goodwill at the end of the period		306,300
Goodwill Impairment Testing
Goodwill included in each component tested		306,300
Information products
Goodwill
Goodwill at the beginning of the period	70,243
Change in foreign currency translation adjustment	(945)
Goodwill at the end of the period	69,298
Goodwill Impairment Testing
Goodwill included in each component tested	69,298
US Information Products
Goodwill
Goodwill at the end of the period		51,200
Goodwill Impairment Testing
Goodwill included in each component tested		$ 51,200