Summary of Significant Accounting Policies Summary of Significant Accounting Policies, Revenue Recognition (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 987,535	$ 820,035	$ 2,065,516	$ 1,623,000
Gross profit	268,713	218,767	646,220	397,811
Costs of revenue	(718,822)	(601,268)	(1,419,296)	(1,225,189)
Corporate general and administrative expenses	(29,038)	(37,169)	(65,771)	(68,982)
Gains on divestitures and impairment charges, net	6,162	737	7,428	5,282
Operating income	245,837	182,335	587,877	334,111
Interest expense	(37,435)	(41,767)	(73,247)	(86,118)
Losses on early extinguishment of debt, net	5,226	11	5,226	150
Nonoperating Income (Expense)	655	1,166	996	(81)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	203,831	141,723	510,400	247,762
Income Tax Expense (Benefit)	(46,042)	(36,170)	(123,656)	(60,208)
Net income	157,789	105,553	386,744	187,554
Net income attributable to noncontrolling interests	(84)	(45)	(160)	(105)
Net income attributable to common stockholders	$ 157,705	$ 105,508	$ 386,584	$ 187,449
Net income attributable to common stockholders, basic	$ 0.94	$ 0.59	$ 2.29	$ 1.04
Net income attributable to common stockholders, diluted	$ 0.92	$ 0.59	$ 2.25	$ 1.03
Change in amounts due for unfulfilled performance obligations			$ (40,933)	$ (18,151)
Financing Receivable, Allowance for Credit Loss, Noncurrent	$ (5,351)		(5,351)		$ (6,902)
Notes Receivable [Member]
Financing Receivable, Allowance for Credit Loss, Noncurrent	$ (4,389)		$ (4,389)		$ (5,957)