Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Statement of Cash Flows [Abstract]
Net income (loss)	$ 209,560	$ 167,027
Bad debt expense	679	514
Deferred financing cost amortization	323	212
Depreciation and amortization	34,699	26,051
Gain (Loss) on Disposition of Property Plant Equipment	(156)	(1,576)
Non-cash compensation expense	9,416	4,333
Deferred income taxes	477	3,823
Unrealized Gain (Loss) on Investments	(4,098)	3,342
Increase (Decrease) in Debt Securities, Trading, and Equity Securities, FV-NI	27,714	0
Accounts receivable	(64,223)	(80,266)
Inventories	4,467	(11,200)
Costs and estimated earnings in excess of billings	(14,605)	(699)
Prepaid expenses and other current assets	(14,275)	(37,262)
Other non-current assets	(1,368)	208
Accounts payable and accrued expenses	24,047	31,299
Billings in excess of costs and estimated earnings	(4,169)	34,790
Other non-current liabilities	1,035	1,025
Net cash provided by operating activities	154,095	141,621
Capital expenditures	(47,270)	(30,891)
Proceeds from sale of assets	680	2,572
Payments to Acquire Investments	44,900	380
Payments to Acquire Businesses, Net of Cash Acquired	22,609	67,698
Net cash used in investing activities	(114,099)	(96,397)
Borrowings of debt	996,400	2,089,870
Repayments of debt	(976,400)	(2,089,870)
Cash paid for finance leases	(3,251)	(2,978)
Payment for Contingent Consideration Liability, Financing Activities	0	4,074
Distribution to noncontrolling interest	7,536	13,533
Purchase of treasury stock	(41,593)	(24,320)
Options exercised	0	8
Net cash used in financing activities	(32,380)	(76,097)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	7,616	(30,873)
CASH, CASH EQUIVALENTS, beginning of period	100,832	75,770
CASH, CASH EQUIVALENTS, end of period	108,448	44,897
Cash paid for interest	564	405
Cash paid for income taxes (net)	94,078	57,790
Payments for Repurchase of Redeemable Noncontrolling Interest	$ 0	$ (31,200)