Derivative Instruments Gain (Loss) (Details) - Interest Rate Swap [Member] - Other Nonoperating Income (Expense) [Member] - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Derivative [Line Items]
Gain (Loss) on Senior Subordinated Convertible Debentures	$ (17,573)	$ (2,642)
Gain (Loss) on Interest Rate Swap	$ 17,005	$ 2,034