Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 202,980	$ (153,741)	$ (183,990)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	176,400	237,376	261,185
Equity in earnings of unconsolidated joint ventures	(39,104)	(23,279)	(80,990)
Distribution of earnings from unconsolidated joint ventures	46,358	90,158	65,954
Non-cash stock compensation	44,742	54,229	63,812
Prepayment premium on redemption of unsecured senior notes	117,500	16,986
Impairment of long-lived assets, including goodwill	105,194	336,472	615,400
Loss on disposal activities			10,381
Loss (gain) on sale of discontinued operations	52,532	(161,900)
Foreign currency translation	(42,728)	(31,919)	(19,099)
Deferred income tax (benefit) expense	(48,265)	11,130	(98,015)
Other	16,063	32,028	5,899
Changes in operating assets and liabilities, net of effects of acquisitions:
Accounts receivable and contract assets	533,006	(136,955)	(316,487)
Prepaid expenses and other assets	(100,526)	(31,815)	(16,576)
Accounts payable	(250,142)	(192,980)	251,410
Accrued expenses and other current liabilities	(84,073)	118,441	259,572
Contract liabilities	103,999	128,312	7,559
Other long-term liabilities	(129,266)	37,079	(48,399)
Net cash provided by operating activities	704,670	329,622	777,616
CASH FLOWS FROM INVESTING ACTIVITIES:
(Payment for) proceeds from sale of discontinued operations, net of cash disposed	(265,876)	2,218,866
Proceeds from disposal of businesses, net of cash disposed			46,490
Investment in unconsolidated joint ventures	(57,388)	(111,077)	(141,769)
Return of investment in unconsolidated joint ventures	8,110	28,047	22,750
Proceeds from sale of investments	15,507	12,392	12,365
Payments for purchase of investments			(3,223)
Proceeds from disposal of property and equipment	14,822	3,800	17,291
Payments for capital expenditures	(136,262)	(114,591)	(100,664)
Net cash (used in) provided by investing activities	(421,087)	2,037,437	(146,760)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from borrowings under credit agreements	3,638,916	4,452,078	7,700,774
Repayments of borrowings under credit agreements	(2,726,347)	(5,568,320)	(7,984,624)
Redemption of unsecured senior notes	(797,252)	(248,522)
Prepayment premium on redemption of unsecured senior notes	(117,500)	(16,986)
Cash paid for debt issuance costs	(11,280)	(4,228)
Proceeds from issuance of common stock	25,686	26,388	30,448
Proceeds from exercise of stock options	4,038
Payments to repurchase common stock	(867,091)	(186,953)	(98,208)
Net distributions to noncontrolling interests	(10,274)	(60,642)	(69,988)
Other financing activities	(11,429)	(20,785)	(11,681)
Net cash used in financing activities	(872,533)	(1,627,970)	(433,279)
EFFECT OF EXCHANGE RATE CHANGES ON CASH	5,493	(1,194)	(3,956)
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(583,457)	737,895	193,621
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	1,818,249	1,080,354	886,733
CASH AND CASH EQUIVALENTS AT END OF YEAR	1,234,792	1,818,249	1,080,354
LESS: CASH AND CASH EQUIVALENTS INCLUDED IN CURRENT ASSETS HELD FOR SALE	(5,596)	(109,917)	(194,715)
CASH AND CASH EQUIVALENTS OF CONTINUING OPERATIONS AT END OF YEAR	1,229,196	1,708,332	885,639
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	(255,679)	(201,402)	(222,263)
Net income taxes (paid) refund received	$ 114,464	$ 71,031	$ (2,500)