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			5 Months Ended	6 Months Ended
	Jun. 30, 2020	May 31, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	May 31, 2020	Jun. 30, 2019
Numerator:
Net loss (numerator for basic EPS)	$ (9,817)	$ (35,121)	$ (69,104)	$ (12,944)	$ (15,115)	$ (104,225)	$ (28,059)
Interest on Convertible Notes, net of tax	0	0		0		0	0
Numerator for diluted EPS, if-converted method	$ (9,817)	$ (35,121)		$ (12,944)		$ (104,225)	$ (28,059)
Denominator:
Weighted-average shares (denominator for basic EPS)	1,048	79,288		78,430		78,968	78,371
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	1,048	79,288		78,430		78,968	78,371
Loss per common share - Basic	$ (9.37)	$ (0.44)		$ (0.17)		$ (1.32)	$ (0.36)
Loss per common share - Diluted	$ (9.37)	$ (0.44)		$ (0.17)		$ (1.32)	$ (0.36)
Potentially dilutive securities excluded as anti-dilutive	9,733	4,103		4,858		4,517	3,709