Share-Based and Other Deferred Compensation - Additional information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Sep. 30, 2013 Long Term Incentive Plan [Member]	Mar. 31, 2014 Employee Loans [Member]	Mar. 31, 2013 Employee Loans [Member]	Mar. 31, 2014 Equity Grants [Member] Minimum [Member]	Mar. 31, 2014 Equity Grants [Member] Maximum [Member]	Mar. 31, 2014 Restricted Stock Units (RSUs) [Member] Equity Grants [Member]	Mar. 31, 2013 Restricted Stock Units (RSUs) [Member] Equity Grants [Member]	Mar. 31, 2013 LP Units [Member]	Mar. 31, 2014 Acquisition-Related [Member]	Mar. 31, 2013 Acquisition-Related [Member]	Mar. 31, 2014 Deferred Cash Program [Member]	Mar. 31, 2013 Deferred Cash Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued during period (in shares)						1,798
Weighted average grant date fair value (in dollars per share)				$ 54.29	$ 58.67
Vested units (in shares)						2,039
Awards forfeited (in shares)						91
Deferred compensation, vesting period (in years)											4 years
Compensation expense related to deferred compensation programs											$ 894	$ 992
Compensation expense related to Service-based Award						22,244	20,593
Amortization of LP Units								5,610
Compensation expense related to acquisition related awards									2,241	3,608
Compensation expense related to deferred cash consideration									932	1,049
Long Term Incentive Plan Performance period (in years)	4 years
Long Term Incentive Plan Payment period (in years)	2 years
Requisite service period (in years)		one
Maximum contractual term (in years)		five
Deferred compensation arrangement compensation expense		2,647	1,667
Unamortized deferred compensation		$ 13,378