Segment Information - Intersegment Activity Eliminated in Arriving at Consolidated Totals was Included in "All Other" Category (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 6,191,943	$ 5,928,302	$ 5,632,187
Income taxes (benefit)	618,112	590,160	915,556
Net income (loss)	1,929,149	1,918,080	1,408,306
Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Revenues	(48,559)	(41,285)	(43,941)
Expenses	(18,218)	(24,660)	(32,623)
Income taxes (benefit)	(7,976)	(4,371)	(4,606)
Net income (loss)	$ (22,365)	$ (12,254)	$ (6,712)