Unaudited Condensed Consolidated Statement of Operations Statement - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Unaudited Condensed Consolidated Statement of Operations [Abstract]
Revenue	$ 777,710	$ 749,219
Costs and expenses	(600,545)	(586,296)
Operating profit	177,165	162,923
General and administrative expenses	(42,504)	(38,904)
Gains (losses) on divestitures and impairment charges, net	4,935	(347)
Operating income	139,596	123,672
Interest expense	(40,636)	(43,082)
Loss on early extinguishment of debt	0	(581)
Other expense, net	(434)	(242)
Income before income taxes	98,526	79,767
Benefit from (provision for) income taxes	76,223	(32,313)
Net Income	174,749	47,454
Net income attributable to noncontrolling interests	(47)	(9)
Net income attributable to common stockholders	$ 174,702	$ 47,445
Basic earnings per share:
Net income attributable to common stockholders, basic	$ 0.93	$ 0.24
Basic weighted average number of shares	188,260	194,924
Diluted earnings per share:
Net income attributable to common stockholders, diluted	$ 0.91	$ 0.24
Diluted weighted average number of shares	192,867	198,030
Dividends declared per share	$ 0.13	$ 0.12