Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues	$ 949,525	$ 844,156
Costs and operating expenses:
Cost of revenues	468,961	427,680
Sales and marketing	128,927	106,590
General and administrative	181,399	165,904
Acquisition costs	3,025	36,536
Gains on asset sales	0	(5,242)
Total costs and operating expenses	782,312	731,468
Income from continuing operations	167,213	112,688
Interest income	3,092	925
Interest expense	(111,684)	(100,863)
Other income (expense)	337	(60,710)
Loss on debt extinguishment	(3,503)	0
Income (loss) from continuing operations before income taxes	55,455	(47,960)
Income tax benefit (expense)	(13,393)	10,633
Net income (loss) from continuing operations	42,062	(37,327)
Net income from discontinued operations, net of tax	0	6,216
Net income (loss)	$ 42,062	$ (31,111)
Earnings (loss) per share (EPS):
Basic EPS from continuing operations (in dollars per share)	$ 0.58	$ (0.55)
Basic EPS from discontinued operations (in dollars per share)	0.00	0.09
Basic EPS (in dollars per share)	$ 0.58	$ (0.46)
Weighted-average shares	72,773	68,132
Diluted EPS from continuing operations (in dollars per share)	$ 0.57	$ (0.55)
Diluted EPS from discontinued operations (in dollars per share)	0.00	0.09
Diluted EPS (in dollars per share)	$ 0.57	$ (0.46)
Weighted-average shares for diluted EPS	73,367	68,132