Earnings per Share (EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Numerator:
Income from continuing operations									$ 40,149		$ 181,705		$ 180,039
Income from discontinued operations, net of tax	$ 168,659	$ (8,470)	$ (5,613)	$ (116)	$ 817	$ 32,621	$ 15,157	$ 11,511	154,460		60,106		63,489
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest									194,609		241,811		243,528
Less: Preference stock dividend									8		32		36
Income attributable to common stockholders (numerator for basic EPS)									$ 194,601		$ 241,779		$ 243,492
Denominator:
Weighted-average shares used in basic EPS (in shares)									176,251		187,277		186,332
Dilutive effect of common stock equivalents (shares)									1,198		1,105		1,103
Weighted-average shares used in diluted EPS (in shares)									177,449		188,382		187,435
Basic earnings per share
Continuing operations (in dollars per share)	$ 0.05	$ 0.03	$ 0.17	$ (0.01)	$ 0.26	$ 0.25	$ 0.19	$ 0.26	$ 0.23	[1]	$ 0.97	[1]	$ 0.97	[1]
Discontinued operations (in dollars per share)	0.99	(0.05)	(0.03)	0	0	0.17	0.08	0.06	0.88	[1]	0.32	[1]	0.34	[1]
Net income (in dollars per share)	1.04	(0.02)	0.13	(0.01)	0.27	0.43	0.28	0.32	1.10	[1]	1.29	[1]	1.31	[1]
Diluted earnings per share
Continuing operations (in dollars per share)	0.05	0.03	0.16	(0.01)	0.26	0.25	0.19	0.26	0.23	[1]	0.96	[1]	0.96	[1]
Discontinued operations (in dollars per share)	0.98	(0.05)	(0.03)	0	0	0.17	0.08	0.06	0.87	[1]	0.32	[1]	0.34	[1]
Net income (in dollars per share)	$ 1.03	$ (0.02)	$ 0.13	$ (0.01)	$ 0.26	$ 0.43	$ 0.27	$ 0.32	$ 1.10	[1]	$ 1.28	[1]	$ 1.30	[1]
Anti-dilutive options excluded from diluted earnings per share (in shares)									15,751		12,089		10,267

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