Earnings per Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Income from continuing operations		$ 30,278	$ 50,387	$ 28,849	$ 101,870
Numerator:
(Loss) income from discontinued operations, net of tax		(6,581)	1,208	(7,811)	9,695
Net income		23,697	51,595	21,038	111,565
Less: Preference stock dividend		0	8	8	16
Income attributable to common stockholders (numerator for basic EPS)		$ 23,697	$ 51,587	$ 21,030	$ 111,549
Denominator:
Weighted-average shares used in basic EPS (in shares)		177,192	187,180	181,446	187,004
Dilutive effect of common stock equivalents (in shares)		1,089	934	1,192	1,053
Weighted-average shares used in diluted EPS (in shares)		178,281	188,114	182,638	188,057
Basic (loss) earnings per share:
Continuing operations (in dollars per share)	[1]	$ 0.17	$ 0.27	$ 0.16	$ 0.54
Discontinued operations (in dollars per share)	[1]	(0.04)	0.01	(0.04)	0.05
Net income (in dollars per share)	[1]	0.13	0.28	0.12	0.60
Diluted (loss) earnings per share:
Continuing operations (in dollars per share)	[1]	0.17	0.27	0.16	0.54
Discontinued operations (in dollars per share)	[1]	(0.04)	0.01	(0.04)	0.05
Net income (in dollars per share)	[1]	$ 0.13	$ 0.27	$ 0.12	$ 0.59
Anti-dilutive options excluded from diluted earnings per share (in shares)		16,297	12,453	16,077	11,959

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