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, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 5,295,883	$ 4,667,624	$ 4,455,719
Income taxes (benefit)	743,284	595,025	575,999
Net income (loss)	1,315,114	1,079,667	1,066,246
Intersegment Activity Eliminated in Consolidated Totals [Member]
Segment Reporting Information [Line Items]
Revenues	(48,625)	(48,972)	(49,800)
Expenses	(40,422)	(13,332)	(12,014)
Income taxes (benefit)	(3,338)	(14,503)	(15,375)
Net income (loss)	$ (4,865)	$ (21,137)	$ (22,411)