INCOME TAXES (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended		3 Months Ended								12 Months Ended
	Jan. 31, 2010	Nov. 30, 2009	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2009	Jun. 30, 2009	Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Components of income (loss) before income tax provision (benefit)
Domestic											$ 244,079	$ 207,210	$ (3,053,327)
Foreign											121,118	122,446	(134,870)
INCOME (LOSS) BEFORE INCOME TAX PROVISION (BENEFIT)			102,626	87,156	103,308	72,107	101,720	72,239	74,993	80,704	365,197	329,656	(3,188,197)
Components of income tax expense (benefit)
Federal											75,290	78,224	(1,075,462)
Foreign											18,788	14,066	32,845
State and local											25,356	26,386	(180,586)
Current											39,162	4,729	(405,726)
Deferred											80,272	113,947	(817,477)
Total income tax provision (benefit)			31,858	33,792	26,720	27,064	36,619	26,006	27,671	28,380	119,434	118,676	(1,223,203)
Tax refunds received	459,000									580,000
Realized losses incurred on the sale of securities													1,600,000
Net operating loss carryback period, prior to federal legislation change (in years)		2
Net operating loss carryback period, after federal legislation change (in years)		5
Net operating loss deductions utilized		1,300,000
Reconciliation of the difference between the effective income tax rate and the statutory federal income tax rate
Tax provision (benefit) at statutory U.S. federal income tax rate (as a percent)											35.00%	35.00%	(35.00%)
State income taxes, net of federal income tax benefit (as a percent)											4.90%	2.50%	(3.30%)
Effect of foreign tax rates (as a percent)											(4.60%)	(3.50%)	0.10%
Loss on Canadian restructuring (as a percent)													(2.90%)
Changes in U.K. tax rates on deferred tax assets and liabilities (as a percent)											(2.50%)
Non-deductible goodwill impairment (as a percent)													2.50%
Other, net (as a percent)											(0.10%)	2.00%	0.20%
Effective income tax (benefit) rate (as a percent)											32.70%	36.00%	(38.40%)
United Kingdom tax rate, prior to enacted Finance Act of 2010 (as a percent)			28.00%								28.00%
United Kingdom tax rate, after the enacted Finance Act of 2010 (as a percent)			27.00%								27.00%
One-time tax benefit resulting from tax rate change											8,900
Expected tax rate in fiscal 2012, after additional proposed reductions in the U.K. corporate tax rate (as a percent)			26.00%								26.00%
Expected tax rate in fiscal 2013, after additional proposed reductions in the U.K. corporate tax rate (as a percent)			25.00%								25.00%
Reduction in effective tax rate (as a percent)											1.00%
DEFERRED TAX ASSETS
Accrued compensation and benefits			129,320				129,389				129,320	129,389
Accrued expenses			46,650				55,252				46,650	55,252
Operating loss carryforwards			375,703				270,672				375,703	270,672
Capital loss carryforwards			44,475				42,404				44,475	42,404
Convertible debt obligations			4,609				6,579				4,609	6,579
Foreign tax credit carryforward			45,119				40,617				45,119	40,617
Federal benefit of uncertain tax positions			17,451				8,921				17,451	8,921
Other			6,947				17,691				6,947	17,691
Deferred tax assets			670,274				571,525				670,274	571,525
Valuation allowance			(94,541)				(87,605)				(94,541)	(87,605)
Deferred tax assets after valuation allowance			575,733				483,920				575,733	483,920
DEFERRED TAX LIABILITIES
Basis differences, principally for intangible assets and goodwill			229,879				246,288				229,879	246,288
Depreciation and amortization			295,699				169,069				295,699	169,069
Other			1,780				630				1,780	630
Deferred tax liabilities			527,358				415,987				527,358	415,987
Net deferred tax asset			48,375				67,933				48,375	67,933
Net operating loss to be recognized as an increse in stockholders' equity											4,700
Adjustment to additional paid-in capital, net additional tax benefit with respect to the Equity Unit extinguishment											36,000
U.S. federal deferred tax assets aggregated			683,200								683,200
Required future U.S. earnings for realization of U.S. federal deferred tax assets			4,600,000								4,600,000
Required future foreign source income in U.S. earnings for realization of U.S. federal deferred tax assets			$ 129,000								$ 129,000