Quarterly Financial Information (Schedule of Quarterly Financial Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Quarterly Financial Information [Abstract]
Total revenue	$ 196,792								$ 196,792
Income (loss) before income taxes	(1,009,571)	65,975	(107,555)	(39,701)	65,144	(17,468)	(25,374)	(22,302)	(1,090,851)	$ (70,607)	$ (58,666)
Net income (loss)	$ (866,881)	$ 50,735	$ (93,935)	$ (37,517)	$ 48,480	$ (12,388)	$ (18,591)	$ (17,501)	$ (947,597)	$ (52,012)	$ 60,955
Basic net income (loss) per share	$ (4.65)	$ 0.35	$ (0.66)	$ (0.50)	$ (0.05)	$ (0.16)	$ (0.25)	$ (0.23)	$ (6.92)	$ (0.69)	$ 0.81
Diluted net income (loss) per share	$ (4.65)	$ 0.35	$ (0.66)	$ (0.50)	$ (0.05)	$ (0.16)	$ (0.25)	$ (0.23)	$ (6.92)	$ (0.69)	$ 0.78