Incentive Plans - Summary of FI and Other Similar Deferred Compensation Arrangements (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Deferred Compensation Arrangements [Abstract]
Prepaid Compensation Asset, Beginning Balance			$ 60,433	$ 47,445
Prepaid Compensation Asset, Granted			92,728	72,217
Prepaid Compensation Asset, Settled
Prepaid Compensation Asset, Forfeited			(1,320)	(765)
Prepaid Compensation Asset, Amortization			(57,287)	(44,195)
Prepaid Compensation Asset, Increase in fair value of underlying investments
Prepaid Compensation Asset, Adjustment for estimated forfeitures
Prepaid Compensation Asset, Other			(551)	(217)
Prepaid Compensation Asset, Ending Balance	94,003	74,485	94,003	74,485
Compensation Liability, Beginning Balance			162,422	97,593
Compensation Liability, Granted			92,728	72,217
Compensation Liability, Settled			(54,293)	(22,903)
Compensation Liability, Forfeited			(1,908)	(985)
Compensation Liability, Amortization
Compensation Liability, Increase in fair value of underlying investments	(5,528)	7,519	6,004	7,767
Compensation Liability, Adjustment for estimated forfeitures			6,527	3,175
Compensation Liability, Other			(1,559)	(558)
Compensation Liability, Ending Balance	$ 209,921	$ 156,306	$ 209,921	$ 156,306