Noncontrolling Interests Rollforward (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015	May 02, 2016	Mar. 31, 2016	Mar. 31, 2015
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		$ 676,164	$ 78,478	$ 676,164		$ 78,478		$ 175,785	$ 45,520
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest		18,235	(1,400)	28,272		(1,009)
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest			0			0
Proceeds from (Payments to) Noncontrolling Interests				(39,469)		33,505
APIC reclassified for MEP vesting						826
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				(10,338)		(364)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		510,500		510,500
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				(59)
RE Reclassified for MEP Amortization				5,353
CIVs and Other
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount	[1]	60,229	68,723	60,229		68,723		94,136	36,549
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest	[1]			8,166		(1,331)
Proceeds from (Payments to) Noncontrolling Interests	[1]			(42,073)	[2]	33,505
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				0
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		0		0
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				0
Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		591,735	1,907	591,735		1,907		68,922	1,949
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest				20,106		322
Proceeds from (Payments to) Noncontrolling Interests				2,604
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				(10,338)		(364)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		510,500		510,500
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				(59)
Management Equity Plan [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		24,200	$ 7,848	24,200		7,848		12,727	$ 7,022
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest				0		0
Proceeds from (Payments to) Noncontrolling Interests				6,120		0
APIC reclassified for MEP vesting						$ 826
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				0
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		0		0
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				0
RE Reclassified for MEP Amortization				5,353
EnTrustPermal [Member]
Noncontrolling Interest [Line Items]
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value							$ 403,200
EnTrustPermal [Member] | Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		409,404		409,404				0
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest				10,740
Proceeds from (Payments to) Noncontrolling Interests				0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				(4,536)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		403,200		403,200
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				0
Clarion Partners [Member] | Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		108,205		108,205				0
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest				5,638
Proceeds from (Payments to) Noncontrolling Interests				0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				(2,733)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		105,300		105,300
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				0
RARE Infrastructure, Ltd [Member] | Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		67,757		67,757				67,155
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest				3,364
Proceeds from (Payments to) Noncontrolling Interests				0
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				(2,703)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		0		0
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				(59)
Royce [Member]
Noncontrolling Interest [Line Items]
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest		1,856		3,707	[3]
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	[3]			(2,723)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value	[3]	0		0
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange	[3]			0
Management Equity Plan [Member] | Royce [Member]
Noncontrolling Interest [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	[3]	23,186		23,186				22,202
Other Affiliates [Member] | Noncontrolling Interest [Member]
Noncontrolling Interest [Line Items]
Redeemable Noncontrolling Interest, Equity, Carrying Amount		6,369		6,369				$ 1,767
Net Income (Loss) Attributable to Redeemable Noncontrolling Interest				364
Proceeds from (Payments to) Noncontrolling Interests				2,604
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders				(366)
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value		$ 2,000		2,000
Noncontrolling Interest, Period Increase (Decrease), Foreign Exchange				$ 0

[1] (1) Principally related to VIE and seeded investment products.

[2] (3)Includes the impact related to the adoption of updated consolidation accounting guidance further discussed in Note 2.

[3] (2) Related to Royce management equity plan.