SEGMENT ANALYSIS, Classified by major geographic areas (Details) (USD $) In Thousands	3 Months Ended				9 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010		Sep. 30, 2010
Revenues:
Revenues	$ 868,212	[1]	$ 763,612	[1]	$ 2,565,289	[1]	$ 2,216,268	[1]
Income (Loss) excluding noncontrolling interests and before provision for income taxes:
Income (Loss) excluding noncontrolling interests and before provision for income taxes	78,667	[2]	97,511		335,418	[2]	256,555
Total assets:
Total assets	16,117,109				16,117,109				17,883,081
Goodwill included in geographic area's asset total	71,924				71,924				62,575
United States [Member]
Revenues:
Revenues	752,726		669,673		2,208,322		1,965,424
Income (Loss) excluding noncontrolling interests and before provision for income taxes:
Income (Loss) excluding noncontrolling interests and before provision for income taxes	67,935		91,003		296,857		249,690
Total assets:
Total assets	14,426,663	[3]			14,426,663	[3]			16,369,401	[4]
Goodwill included in geographic area's asset total	32,000				32,000				32,000
Canada [Member]
Revenues:
Revenues	83,478		75,094		270,492		196,685
Income (Loss) excluding noncontrolling interests and before provision for income taxes:
Income (Loss) excluding noncontrolling interests and before provision for income taxes	9,063		7,665		36,861		11,875
Total assets:
Total assets	1,565,019	[4]			1,565,019	[4]			1,443,943	[4]
Goodwill included in geographic area's asset total	33,000				33,000				33,000
Europe [Member]
Revenues:
Revenues	17,416		14,489		50,557		42,392
Income (Loss) excluding noncontrolling interests and before provision for income taxes:
Income (Loss) excluding noncontrolling interests and before provision for income taxes	(781)		83		(2,497)		(899)
Total assets:
Total assets	50,403	[5]			50,403	[5]			28,057	[5]
Goodwill included in geographic area's asset total	7,000				7,000
Other Geographic Areas [Member]
Revenues:
Revenues	14,592		4,356		35,918		11,767
Income (Loss) excluding noncontrolling interests and before provision for income taxes:
Income (Loss) excluding noncontrolling interests and before provision for income taxes	2,450		(1,240)		4,197		(4,111)
Total assets:
Total assets	$ 75,024				$ 75,024				$ 41,680

[1] No individual client accounted for more than ten percent of total revenues.

[2] The Other segment for the period ended June 30, 2011 includes a $45 million pre-tax loss provision for auction rate securities (see further discussion of this matter in Note 13).

[3] Includes $32 million of goodwill.

[4] Includes $33 million of goodwill.

[5] Includes $7 million of goodwill