INCOME TAXES (Details) (USD $)	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009
Recorded in:
Income including noncontrolling interests	$ 182,894,000	$ 133,625,000	$ 96,024,000
Equity, for compensation expense for tax purposes in excess of (less than) amounts recognized for financial reporting purposes	374,000	(2,280,000)	(3,210,000)
Equity, for available for sale securities	1,497,000	17,020,000	(2,963,000)
Total	184,765,000	148,365,000	89,851,000
Current:
Federal	148,266,000	140,482,000	125,557,000
State and local	29,387,000	15,592,000	13,264,000
Foreign	11,249,000	3,380,000	1,875,000
Current provision (benefit) for income taxes	188,902,000	159,454,000	140,696,000
Deferred:
Federal	(6,279,000)	(23,190,000)	(39,266,000)
State and local	(3,887,000)	(2,778,000)	(4,538,000)
Foreign	4,158,000	139,000	(868,000)
Deferred provision (benefit) for income taxes	(6,008,000)	(25,829,000)	(44,672,000)
Provision (benefit) for income taxes	182,894,000	133,625,000	96,024,000
Statutory federal income tax rate (in hundredths)	35.00%	35.00%	35.00%
Income tax reconciliation [Abstract]
Provision calculated at statutory rates	161,436,000	126,667,000	87,071,000
State income taxes, net of federal benefit	16,575,000	8,329,000	5,672,000
Other, net	4,883,000	(1,371,000)	3,281,000
Provision (benefit) for income taxes	182,894,000	133,625,000	96,024,000
U.S. and foreign components of income before income taxes [Abstract]
U.S.	421,662,000	356,067,000	256,659,000
Foreign	39,585,000	5,841,000	(7,885,000)
Income excluding noncontrolling interest and before provision for income taxes	461,247,000	361,908,000	248,774,000
Deferred tax assets:
Deferred compensation	79,192,000	70,445,000
Allowances for loan losses and reserves for unfunded commitments	63,061,000	62,562,000
Interest on nonaccrual loans	366,000	228,000
Unrealized loss	26,381,000	30,460,000
Accrued expenses	16,018,000	15,100,000
Capitalized expenditures	344,000	3,747,000
Net operating loss and credit carryforwards	4,126,000	3,075,000
Other	23,919,000	16,087,000
Total gross deferred tax assets	213,407,000	201,704,000
Less: valuation allowance	(2,536,000)	(3,075,000)
Total deferred tax assets	210,871,000	198,629,000
Deferred tax liabilities:
Aircraft lease	(5,716,000)	(6,793,000)
Undistributed earnings of foreign subsidiaries	(16,517,000)	(16,143,000)
Other	(16,727,000)	(10,485,000)
Total deferred tax liabilities	(38,960,000)	(33,421,000)
Net deferred tax assets	171,911,000	165,208,000
Cumulative amount of undistributed earnings attributable to foreign subsidiaries	118,500,000
Income tax receivable [Abstract]
Current tax receivable	14,900,000	10,900,000
Income tax uncertainties [Abstract]
Decrease in accrued interest expense related to unrecognized tax benefits	56,000
Increase (decrease) in penalty expense related to unrecognized tax benefits	20,000
Accrued interest and penalties related to unrecognized tax benefits	1,300,000	1,400,000
Changes in the liability for unrecognized tax benefits [Roll Forward]
Liability for unrecognized tax benefits at beginning of fiscal year	4,308,000	4,565,000	4,862,000
Increases for tax positions related to the current year	1,199,000	1,108,000	779,000
Increases for tax positions related to prior years	551,000	353,000	219,000
Decreases for tax positions related to prior years	(44,000)	(70,000)	(114,000)
Decreases due to lapsed statute of limitations	(1,284,000)	(1,433,000)	(1,037,000)
Decreases related to settlements	0	(215,000)	(144,000)
Liability for unrecognized tax benefits at end of fiscal year	4,730,000	4,308,000	4,565,000
Unrecognized tax benefits that would affect the effective tax rate	$ 3,800,000