Investments in Partnerships, Offshore Funds and Variable Interest Entities, Part I (Details)	3 Months Ended		9 Months Ended
	Jun. 30, 2015 USD ($) Entity	Jun. 30, 2014 USD ($) Entity	Dec. 31, 2012 Entity	Dec. 31, 2014 USD ($)
Variable Interest Entity [Line Items]
Investments in affiliated entities	$ 95,400,000	$ 93,000,000		$ 94,200,000
Investments in unaffiliated entities	13,600,000	14,900,000		13,400,000
Investments in Partnerships by Accounting Method [Abstract]
Fair value	21,526,000	24,856,000		23,803,000
Equity Method Investments	87,424,000	83,040,000		83,834,000
Total	108,950,000	107,896,000		107,637,000
Maximum exposure to loss related to VIEs	9,800,000	8,900,000		10,600,000
Deferred carried interest in VIE	41,000	47,000		43,000
Total VIE assets	$ 68,000,000	$ 74,400,000		71,600,000
VIE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	1	0	0
Deconsolidated entities | Entity	0	0	0
Entities consolidated at end of period | Entity	2	1
Investments in Partnerships by Accounting Method [Abstract]
Total	$ 11,665,000	$ 14,125,000		13,434,000
VOE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	2	0	0
Deconsolidated entities | Entity	(2)	0	0
Entities consolidated at end of period | Entity	4	4
Prior to Consolidations [Member]
Investments in Partnerships by Accounting Method [Abstract]
Total	$ 107,520,000	$ 112,305,000		111,380,000
CFFs [Member]
Investments in Partnerships by Accounting Method [Abstract]
Total	11,287,000	4,962,000		4,438,000
CFFs [Member] | Affiliated [Member]
Investments in Partnerships by Accounting Method [Abstract]
Fair value	21,526,000	24,856,000		23,803,000
Equity Method Investments	0	0		0
Total	$ 21,526,000	$ 24,856,000		23,803,000
CFFs [Member] | VIE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	0	0	0
Deconsolidated entities | Entity	0	0	0
Entities consolidated at end of period | Entity	1	1
CFFs [Member] | VOE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	1	0	0
Deconsolidated entities | Entity	(1)	0	0
Entities consolidated at end of period | Entity	2	2
Partnerships [Member]
Investments in Partnerships by Accounting Method [Abstract]
Total	$ (9,391,000)	$ (9,371,000)		(8,181,000)
Partnerships [Member] | Affiliated [Member]
Investments in Partnerships by Accounting Method [Abstract]
Fair value	0	0		0
Equity Method Investments	38,515,000	32,830,000		34,385,000
Total	38,515,000	32,830,000		34,385,000
Partnerships [Member] | Unaffiliated [Member]
Investments in Partnerships by Accounting Method [Abstract]
Fair value	0	0		0
Equity Method Investments	6,349,000	6,699,000		6,552,000
Total	$ 6,349,000	$ 6,699,000		6,552,000
Partnerships [Member] | VIE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	0	0	0
Deconsolidated entities | Entity	0	0	0
Entities consolidated at end of period | Entity	0	0
Partnerships [Member] | VOE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	1	0	0
Deconsolidated entities | Entity	0	0	0
Entities consolidated at end of period | Entity	2	1
Offshore Funds [Member]
Investments in Partnerships by Accounting Method [Abstract]
Total	$ (466,000)	$ 0		0
Offshore Funds [Member] | Affiliated [Member]
Investments in Partnerships by Accounting Method [Abstract]
Fair value	0	0		0
Equity Method Investments	35,311,000	35,268,000		36,033,000
Total	35,311,000	35,268,000		36,033,000
Offshore Funds [Member] | Unaffiliated [Member]
Investments in Partnerships by Accounting Method [Abstract]
Fair value	0	0		0
Equity Method Investments	7,249,000	8,243,000		6,864,000
Total	$ 7,249,000	$ 8,243,000		$ 6,864,000
Offshore Funds [Member] | VIE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	1	0	0
Deconsolidated entities | Entity	0	0	0
Entities consolidated at end of period | Entity	1	0
Offshore Funds [Member] | VOE [Member]
Entities Consolidated [Roll Forward]
Additional consolidated entities | Entity	0	0	0
Deconsolidated entities | Entity	(1)	0	0
Entities consolidated at end of period | Entity	0	1