Earnings Per Share and Weighted-Average Shares Outstanding - Additional Information (Detail) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of fully diluted earnings per share amount	61.8	77.4	85.4	70.7
Limited Partnership Interests [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of fully diluted earnings per share amount	61.7	77.4	84.9	70.5
RSUs [Member]
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from computation of fully diluted earnings per share amount	0.1		0.5	0.2