Unaudited Condensed Consolidated Statement of Operations Statement - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Unaudited Condensed Consolidated Statement of Operations [Abstract]
Revenue	$ 749,271	$ 748,117
Costs and expenses	(587,775)	(570,673)
Gross profit	161,496	177,444
General and administrative expenses	(37,508)	(34,550)
Losses on divestitures and impairment charges, net	(347)	(1,779)
Operating income	123,641	141,115
Interest expense	(43,082)	(42,939)
Loss on early extinguishment of debt	(581)	0
Other expense, net	(211)	(58)
Income before income taxes	79,767	98,118
Provision for income taxes	(32,313)	(36,653)
Net income	47,454	61,465
Net income attributable to noncontrolling interests	(9)	(90)
Net income attributable to common stockholders	$ 47,445	$ 61,375
Basic earnings per share:
Net income attributable to common stockholders, basic	$ 0.24	$ 0.30
Basic weighted average number of shares	194,924	203,510
Diluted earnings per share:
Net income attributable to common stockholders, diluted	$ 0.24	$ 0.30
Diluted weighted average number of shares	198,030	207,752
Dividends declared per share	$ 0.12	$ 0.10