Treasury Stock Acquisition (Detail) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Treasury Stock [Line Items]
Treasury shares at beginning of period			77,336,387				77,336,387
Treasury shares at end of period	83,385,203						83,385,203
Treasury shares at beginning of period			$ 1,345,134				$ 1,345,134
Treasury stock acquired, cost	$ 194	$ 910	$ 20,025	$ 76,123	$ 88,258	$ 75,113	21,129	$ 239,494
Treasury shares at end of period	$ 1,366,263						$ 1,366,263
Stock Buyback Program
Schedule of Treasury Stock [Line Items]
Treasury stock acquired, shares							5,826,266
Treasury stock acquired, cost							$ 20,000
Long Term Incentive Plan
Schedule of Treasury Stock [Line Items]
Treasury stock acquired, shares							222,550
Treasury stock acquired, cost							$ 1,129