Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Statement of Cash Flows [Abstract]
Net income (loss)	$ 40,554	$ 33,478	$ (13,803)
Bad debt expense	1,864	552	421
Deferred financing cost amortization	152	318	288
Depreciation and amortization	12,508	9,557	8,860
Loss (gain) on sale of assets	0	(52)	15
Non-cash compensation	3,323	2,357	(136)
Goodwill impairment expense	6,976	0	0
Deferred income taxes	5,122	5,681	38,151
Accounts receivable	(25,389)	(35,254)	(7,574)
Inventories	(2,822)	(684)	(3,970)
Costs and estimated earnings in excess of billings	435	1,586	(17,840)
Prepaid expenses and other current assets	(9,355)	(7,171)	(2,250)
Other non-current assets	510	(444)	274
Accounts payable and accrued expenses	20,122	22,472	6,584
Billings in excess of costs and estimated earnings	13,967	6,683	3,570
Other non-current liabilities	8,774	(459)	(336)
Net cash provided by operating activities	76,741	38,724	12,224
Purchases of property and equipment	4,745	6,300	4,563
Proceeds from sale of assets	104	502	108
Cash received (paid) in conjunction with business combinations	(28,952)	50	(7,406)
Net cash used in investing activities	(33,593)	(5,748)	(11,861)
Borrowings of debt	592,768	89,261	168
Repayments of debt	(592,756)	(119,508)	(177)
Finance lease payment	(215)	0	0
Distribution to noncontrolling interests	(639)	(240)	(349)
Purchase of treasury stock	(7,697)	(9,802)	(2,059)
Issuance of shares	34	0	11
Net cash used in financing activities	(8,505)	(40,289)	(2,406)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	34,643	(7,313)	(2,043)
CASH, CASH EQUIVALENTS and RESTRiCTED CASH, beginning of period	18,934	26,247	28,290
CASH, CASH EQUIVALENTS and RESTRICTED CASH, end of period	53,577	18,934	26,247
Cash paid for interest	782	1,743	1,684
Cash paid for income taxes (net)	$ 323	$ 1,370	$ 2,839