Share-Based Compensation - Schedule of Share and Dividend Equivalent Share Award Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Value of share equivalents
Market price of Company's stock	$ 71.71	$ 78.0
Phantom Stock and Performance Stock Units
Number of share equivalents
Balance at beginning of the period (in shares)	353,407,000	393,844,000
Granted (in shares)	161,273,000	129,234,000
Forfeited share equivalents (in shares)	(13,680,000)	(24,460,000)
Vested share equivalents (in shares)	(96,995,000)	(121,758,000)
Balance at end of the period (in shares)	404,005,000	376,860,000
Value of share equivalents
Balance at beginning of the period (in shares)	$ 22,717	$ 30,523
Granted (in shares)	11,565	10,080
Forfeited share equivalents (in shares)	981	1,908
Vested share equivalents (in shares)	7,316	10,187
Balance at end of the period (in shares)	$ 28,971	$ 29,395