Corporate Debt (Carrying Values of Corporate Debt) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Debt Instrument [Line Items]
Corporate debt	$ 857,918	$ 1,117,050
Senior Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Senior revolving credit facility	338,474	99,750
Senior Secured Second-Priority Notes [Member]
Debt Instrument [Line Items]
Corporate debt	432,277	431,510
Term Loan [Member]
Debt Instrument [Line Items]
Corporate debt	0	477,514
Convertible Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Corporate debt	87,167	104,498
Other Financing Obligations [Member]
Debt Instrument [Line Items]
Corporate debt	$ 0	$ 3,778