Earnings per Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Income from continuing operations		$ 5,345	$ 47,656	$ 32,112	$ 132,553
Numerator:
(Loss) income from discontinued operations, net of tax		(8,470)	32,621	(14,199)	59,289
Net (loss) income		(3,125)	80,277	17,913	191,842
Less: Preference stock dividend		0	8	8	24
(Loss) income attributable to common stockholders (numerator for basic EPS)		$ (3,125)	$ 80,269	$ 17,905	$ 191,818
Denominator:
Weighted-average shares used in basic EPS (in shares)		170,326	187,470	178,048	187,167
Dilutive effect of common stock equivalents (in shares)		875	945	1,048	1,023
Weighted-average shares used in diluted EPS (in shares)		171,201	188,415	179,096	188,190
Basic earnings (loss) per share:
Continuing operations (in dollars per share)	[1]	$ 0.03	$ 0.25	$ 0.18	$ 0.71
Discontinued operations (in dollars per share)	[1]	(0.05)	0.17	(0.08)	0.32
Net (loss) income (in dollars per share)	[1]	(0.02)	0.43	0.10	1.02
Diluted earnings (loss) per share:
Continuing operations (in dollars per share)	[1]	0.03	0.25	0.18	0.70
Discontinued operations (in dollars per share)	[1]	(0.05)	0.17	(0.08)	0.32
Net (loss) income (in dollars per share)	[1]	$ (0.02)	$ 0.43	$ 0.10	$ 1.02
Anti-dilutive options excluded from diluted earnings per share (in shares)		16,182	12,195	16,166	12,097

[1] The sum of the earnings per share amounts may not equal the totals due to rounding.