Investments in Unconsolidated Subsidiaries - Schedule of Condensed Financial Information of Equity Method Investments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Schedule of Equity Method Investments [Line Items]
Revenue	$ 6,798,327	$ 5,645,142	$ 19,195,819	$ 16,915,694
Operating income	409,665	211,408	1,045,231	525,863
Net income	436,622	184,840	1,149,041	440,482
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Schedule of Equity Method Investments [Line Items]
Revenue	636,229	513,792	2,098,850	1,337,212
Operating income	375,655	97,833	1,082,656	411,291
Net income	$ 909,341	$ 109,251	$ 2,386,276	$ 267,835