Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended			9 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Class A Common Stock [Member]	Dec. 31, 2013 Class A Common Stock [Member]	Jun. 30, 2013 Class A Common Stock [Member] Global Partnership Restructuring Program [Member]	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]	Sep. 30, 2013 Restricted Stock [Member]	Jun. 30, 2013 Restricted Stock [Member] Global Partnership Restructuring Program [Member]	Sep. 30, 2014 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2014 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2013 Restricted Stock Units (RSUs) [Member]	Dec. 31, 2013 Restricted Stock Units (RSUs) [Member]	Sep. 30, 2014 Restricted Stock Units (RSUs) [Member] Minimum [Member]	Sep. 30, 2014 Restricted Stock Units (RSUs) [Member] Maximum [Member]	Sep. 30, 2014 Equity Options [Member]	Sep. 30, 2013 Equity Options [Member]	Sep. 30, 2014 Limited Partnership Units [Member]	Sep. 30, 2013 Limited Partnership Units [Member]	Sep. 30, 2014 Limited Partnership Units [Member]	Sep. 30, 2013 Limited Partnership Units [Member]	Sep. 30, 2014 Limited Partnership Units [Member] Minimum [Member]	Sep. 30, 2014 Limited Partnership Units [Member] Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized to be delivered pursuant to awards granted						300,000,000
Aggregate number of shares grant of future awards	148,100,000		148,100,000
Number of limited partnership units granted exchangeability																						6,600,000	800,000	12,900,000	5,800,000
Equity-based compensation expense													$ 1,300,000	$ 1,200,000	$ 4,200,000	$ 4,500,000						$ 47,300,000	$ 5,400,000	$ 96,500,000	$ 28,900,000
Number of limited partnership units exchangeable into shares	1,700,000		1,700,000		1,900,000
Notional value with post-termination pay-out amount	56,700,000		56,700,000		35,100,000
Aggregate estimated fair value of limited partnership units held by employees	10,100,000		10,100,000		5,500,000
Number of unvested limited partnership units	5,700,000		5,700,000		4,100,000
Number of outstanding limited partnership units	10,300,000		10,300,000		7,200,000
Restricted shares, restriction period																		2 years	4 years							3 years	5 years
Compensation expense related to limited partnership units that were not redeemed																						1,400,000	700,000	4,800,000	4,500,000
Income allocated to limited partnership units	5,200,000	4,900,000	9,800,000	58,500,000
Restricted stock unit, Conversion description			Each RSU is settled in one share of Class A common stock upon completion of the vesting period.
Awards granted															899,118	1,300,000								33,735,993
Aggregate estimated grant date fair values															5,200,000	3,800,000
Value of shares withheld															800,000	1,000,000
Aggregate estimated grant date fair value of outstanding RSUs													10,500,000		10,500,000		12,700,000
Unrecognized compensation expense related to unvested RSUs													11,800,000		11,800,000
Shares granted						217,011,000	202,671,000	44,000,000				41,000,000
Non-cash, non-dilutive compensation charges											304,100,000
Restricted shares saleable period									5 years	10 years
Number of shares released the restrictions			7,300,000		5,900,000
Options granted during the period																				0	0
Exercised options																				0	0
Compensation expense related to stock options	0	0	0	0
Unrecognized compensation expense related to unvested stock options																				$ 0