Fair Value of Financial Instruments (Tables)

9 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Carrying amounts and fair values of subordinated convertible debentures

The following table shows the carrying amounts and fair values of the Company's senior and junior subordinated convertible debt as of December 31, 2017 and March 31, 2017 (amounts in thousands). As of December 31, 2017 and March 31, 2017, the carrying amounts of the Company's senior and junior subordinated convertible debt have been reduced by debt issuance costs of $35.2 million and $38.3 million, respectively.

	December 31, 2017				March 31, 2017
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
2017 Senior Debt	$	1,424,169	$	2,436,742	$	1,384,914	$	2,106,225
2015 Senior Debt	$	1,297,605	$	2,952,993	$	1,261,787	$	2,481,708
2017 Junior Debt	$	324,528	$	814,329	$	262,298	$	586,609
2007 Junior Debt	$	—	$	—	$	49,952	$	445,142