Cost Saving Initiatives - Schedule of Expenses and Cumulative Expenses Associated With Implementation of Cost Saving Initiatives (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended	15 Months Ended
	Dec. 31, 2013	Dec. 31, 2013
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	$ 64,703	$ 167,279
Compensation and Benefits [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	51,399	151,386
Other [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	13,304	15,893
Operating Segments [Member] | Financial Advisory [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	47,779	125,311
Operating Segments [Member] | Financial Advisory [Member] | Compensation and Benefits [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	45,746	121,879
Operating Segments [Member] | Financial Advisory [Member] | Other [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	2,033	3,432
Operating Segments [Member] | Asset Management [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	235	13,024
Operating Segments [Member] | Asset Management [Member] | Compensation and Benefits [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	236	12,292
Operating Segments [Member] | Asset Management [Member] | Other [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	(1)	732
Corporate [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	16,689	28,944
Corporate [Member] | Compensation and Benefits [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	5,417	17,215
Corporate [Member] | Other [Member]
Restructuring and Related Cost [Abstract]
Cost Saving Initiatives	$ 11,272	$ 11,729