Earnings (Loss) Per Common Share (Reconciliation of Earnings (loss) Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended					4 Months Ended	5 Months Ended	9 Months Ended
	Jun. 30, 2020	May 31, 2020	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	May 31, 2020	Sep. 30, 2019
Numerator:
Net loss (numerator for basic EPS)	$ (9,817)	$ (35,121)	$ (20,070)	$ (69,104)	$ (26,016)	$ (12,944)	$ (15,115)	$ (29,887)	$ (104,225)	$ (54,075)
Interest on Convertible Notes, net of tax			0		0			0	0	0
Numerator for diluted EPS, if-converted method			$ (20,070)		$ (26,016)			$ (29,887)	$ (104,225)	$ (54,075)
Denominator:
Weighted-average shares (denominator for basic EPS)			1,119		78,473			1,101	78,968	78,405
Potentially dilutive shares issuable from Convertible Notes, if-converted method			0		0			0	0	0
Potentially dilutive shares issuable from outstanding stock-based compensation awards, treasury stock method			0		0			0	0	0
Denominator for diluted EPS			1,119		78,473			1,101	78,968	78,405
Loss per common share - Basic			$ (17.94)		$ (0.33)			$ (27.15)	$ (1.32)	$ (0.69)
Loss per common share - Diluted			$ (17.94)		$ (0.33)			$ (27.15)	$ (1.32)	$ (0.69)
Potentially dilutive securities excluded as anti-dilutive			9,733		5,577			9,733	4,517	4,962