Corporate Debt (Narrative - Convertible Senior Subordinated Notes) (Details) (USD $)	12 Months Ended											0 Months Ended	12 Months Ended			0 Months Ended		12 Months Ended									3 Months Ended				1 Months Ended		3 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2013 Convertible Senior Subordinated Notes [Member]	Mar. 31, 2012 Convertible Senior Subordinated Notes [Member]	Mar. 31, 2011 Convertible Senior Subordinated Notes [Member]	Mar. 31, 2013 Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]		Mar. 31, 2012 Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Mar. 31, 2011 Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Oct. 31, 2004 Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Jul. 17, 2012 Convertible Senior Subordinated Notes [Member] February 2005 Notes [Member]	Mar. 31, 2013 Convertible Senior Subordinated Notes [Member] February 2005 Notes [Member]	Mar. 31, 2012 Convertible Senior Subordinated Notes [Member] February 2005 Notes [Member]	Mar. 31, 2011 Convertible Senior Subordinated Notes [Member] February 2005 Notes [Member]	Mar. 21, 2013 Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Sep. 19, 2012 Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Mar. 31, 2013 Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]		Mar. 31, 2012 Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Mar. 31, 2011 Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Apr. 30, 2009 Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Mar. 31, 2013 Convertible Senior Subordinated Notes [Member] January 2012 Notes [Member]		Mar. 31, 2012 Convertible Senior Subordinated Notes [Member] January 2012 Notes [Member]	Jan. 11, 2012 Convertible Senior Subordinated Notes [Member] January 2012 Notes [Member]	Mar. 31, 2013 Issuer [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Mar. 31, 2013 Issuer [Member] On or After March 15, 2015 [Member] Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Mar. 31, 2013 Holder [Member] Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Mar. 31, 2013 Holder [Member] On October 15, 2014, October 15, 2019 or Upon a Change in Control [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Oct. 17, 2011 October 2011 Debt Redemption [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	May 31, 2011 May 2011 Debt Repurchase [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Jun. 30, 2011 May 2011 Debt Repurchase [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Mar. 31, 2013 Common Shares [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Jul. 17, 2012 Common Shares [Member] Convertible Senior Subordinated Notes [Member] February 2005 Notes [Member]	Mar. 31, 2013 Common Shares [Member] Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Jan. 11, 2012 Common Shares [Member] Convertible Senior Subordinated Notes [Member] January 2012 Notes [Member]	Mar. 31, 2013 Common Shares [Member] Minimum [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Mar. 31, 2013 Common Shares [Member] Minimum [Member] Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]	Mar. 31, 2013 Common Shares [Member] Maximum [Member] Convertible Senior Subordinated Notes [Member] October 2004 Notes [Member]	Mar. 31, 2013 Common Shares [Member] Maximum [Member] Convertible Senior Subordinated Notes [Member] April 2009 Notes [Member]
Principal amount of notes											$ 150,000,000											$ 66,600,000				$ 45,000,000
Debt instrument, repurchase amount																															27,000,000	19,500,000
Principal amount of notes repurchased		125,000																													26,600,000	19,400,000
Write-off of deferred debt financing costs																																	100,000
Coupon rate							2.9375%		2.9375%	2.9375%			3.625%		3.625%			3.625%					4.00%		4.00%
Principal amount of debt redeemed												23,500,000
Principal amount of debt redeemed for cash												7,700,000
Principal amount of convertible senior subordinated notes converted				17,897,000	0	99,718,000						15,800,000	15,825,000	0	0	1,100,000	1,000,000	2,072,000		0	0
Common shares issued for convertible senior subordinated notes conversion												1,107,950	1,107,950			129,090	122,060	251,150
Equity component							50,100,000											16,200,000					10,100,000
Loss on extinguishment of debt	(24,089,000)	(967,000)	(14,505,000)	(24,089,000)	(967,000)	(14,505,000)																											(500,000)
Principal amount of debt outstanding	884,327,000			109,853,000	135,393,000		348,000	[1],[2]	348,000				0	23,464,000				64,505,000	[1],[2]	66,581,000			45,000,000	[1],[2]	45,000,000
Carrying value of debt outstanding	857,918,000	1,117,050,000		87,167,000	104,498,000		348,000		348,000				0	23,464,000				49,907,000		45,462,000			36,912,000		35,224,000
Carrying value of notes extinguished																															26,600,000	18,900,000
Debt instrument redemption price percentage												100.00%															100.00%	100.00%	100.00%	100.00%	100.00%
Conversion rate of number of common shares of the company per $1,000 principal amount of new notes																																		86.9565	70.0133	121.2121
Debt instrument, denomination amount				$ 1,000
Conversion price per share							$ 11.50						$ 14.28					$ 8.25					$ 10.50											$ 11.50	$ 14.28	$ 8.25	$ 10.50
Applicable price range for make-whole premium																																						$ 8.79	$ 5.36	$ 50.00	$ 50.00

[1] Subsequent to March 31, 2013, on April 15, 2013, LGEI sold $60.0 million in aggregate principal amount of 1.25% convertible senior subordinated Notes with a maturity date of April 15, 2018 that are not included in the table above (see Note 25 for further detail).

[2] The future repayment dates of the convertible senior subordinated notes represent the next redemption date by holders for each series of notes respectively, as described below.