Share-Based And Other Deferred Compensation (Narrative) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012 Y	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service-based Awards vested			1,687
Service-based Awards forfeited			366
Awarded deferred cash compensation					$ 3,926
Awarded deferred cash compensation, vesting period, years	4
Compensation expense related to deferred compensation program	1,053	475	3,318	1,310
Compensation expense related to service-based awards	15,654	11,720	46,353	35,290
Compensation expense related to amortization of LP units	5,464	4,833	15,293	15,808
Compensation expense related to acquisition related awards	4,457	2,075	15,089	2,075
Compensation expense related to deferred cash consideration	2,036	910	6,657	910
Event based award vested				546
Event based award vested expenses				11,467
Compensation expense related to modification of equity based compensation awards				1,646
Separation benefits, expenses	151		6,865
Cash payments related to separation benefits	$ 271		$ 4,947
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair values per share			$ 22.62
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair values per share			$ 29.19
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service-based Awards granted			3,064