Summary of Significant Accounting Policies Summary of Significant Accounting Policies, Revenue Recognition (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue	$ 1,077,981	$ 802,965
Gross profit	377,507	179,044
Costs of revenue	(700,474)	(623,921)
Corporate general and administrative expenses	(36,733)	(31,813)
Gains on divestitures and impairment charges, net	1,266	4,545
Operating income	342,040	151,776
Interest expense	(35,812)	(44,351)
Losses on early extinguishment of debt, net	0	139
Nonoperating Income (Expense)	341	(1,247)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	306,569	106,039
Income Tax Expense (Benefit)	(77,614)	(24,038)
Net income	228,955	82,001
Net income attributable to noncontrolling interests	(76)	(60)
Net income attributable to common stockholders	$ 228,879	$ 81,941
Net income attributable to common stockholders, basic	$ 1.35	$ 0.45
Net income attributable to common stockholders, diluted	$ 1.33	$ 0.45
Change in amounts due for unfulfilled performance obligations	$ (10,387)	$ (2,555)
Financing Receivable, Allowance for Credit Loss, Noncurrent	(6,297)		$ (6,902)
Notes Receivable [Member]
Financing Receivable, Allowance for Credit Loss, Noncurrent	$ (5,315)		$ (5,957)