Unaudited Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 354,939,000	$ (173,579,000)	$ 185,650,000	$ (237,286,000)
Other comprehensive loss	(13,000)	(59,000)	(24,000.000)	(434,000)
Comprehensive income (loss)	$ 354,926,000	$ (173,638,000)	$ 185,626,000	$ (237,720,000)